doom3-bfg/neo/libs/ffmpeg-win32/doc/ffplay-all.html
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<h1 class="settitle">ffplay Documentation</h1>
<a name="SEC_Contents"></a>
<h1>Table of Contents</h1>
<div class="contents">
<ul class="toc">
<li><a name="toc-Synopsis" href="#Synopsis">1. Synopsis</a></li>
<li><a name="toc-Description" href="#Description">2. Description</a></li>
<li><a name="toc-Options-9" href="#Options-9">3. Options</a>
<ul class="toc">
<li><a name="toc-Stream-specifiers-1" href="#Stream-specifiers-1">3.1 Stream specifiers</a></li>
<li><a name="toc-Generic-options" href="#Generic-options">3.2 Generic options</a></li>
<li><a name="toc-AVOptions" href="#AVOptions">3.3 AVOptions</a></li>
<li><a name="toc-Main-options" href="#Main-options">3.4 Main options</a></li>
<li><a name="toc-Advanced-options" href="#Advanced-options">3.5 Advanced options</a></li>
<li><a name="toc-While-playing" href="#While-playing">3.6 While playing</a></li>
</ul></li>
<li><a name="toc-Syntax" href="#Syntax">4. Syntax</a>
<ul class="toc">
<li><a name="toc-Quoting-and-escaping" href="#Quoting-and-escaping">4.1 Quoting and escaping</a>
<ul class="toc">
<li><a name="toc-Examples-79" href="#Examples-79">4.1.1 Examples</a></li>
</ul></li>
<li><a name="toc-Date" href="#Date">4.2 Date</a></li>
<li><a name="toc-Time-duration" href="#Time-duration">4.3 Time duration</a>
<ul class="toc">
<li><a name="toc-Examples-65" href="#Examples-65">4.3.1 Examples</a></li>
</ul></li>
<li><a name="toc-Video-size" href="#Video-size">4.4 Video size</a></li>
<li><a name="toc-Video-rate" href="#Video-rate">4.5 Video rate</a></li>
<li><a name="toc-Ratio" href="#Ratio">4.6 Ratio</a></li>
<li><a name="toc-Color" href="#Color">4.7 Color</a></li>
<li><a name="toc-Channel-Layout" href="#Channel-Layout">4.8 Channel Layout</a></li>
</ul></li>
<li><a name="toc-Expression-Evaluation" href="#Expression-Evaluation">5. Expression Evaluation</a></li>
<li><a name="toc-OpenCL-Options" href="#OpenCL-Options">6. OpenCL Options</a></li>
<li><a name="toc-Codec-Options" href="#Codec-Options">7. Codec Options</a></li>
<li><a name="toc-Decoders" href="#Decoders">8. Decoders</a></li>
<li><a name="toc-Video-Decoders" href="#Video-Decoders">9. Video Decoders</a>
<ul class="toc">
<li><a name="toc-rawvideo-1" href="#rawvideo-1">9.1 rawvideo</a>
<ul class="toc">
<li><a name="toc-Options-12" href="#Options-12">9.1.1 Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Audio-Decoders" href="#Audio-Decoders">10. Audio Decoders</a>
<ul class="toc">
<li><a name="toc-ac3" href="#ac3">10.1 ac3</a>
<ul class="toc">
<li><a name="toc-AC_002d3-Decoder-Options" href="#AC_002d3-Decoder-Options">10.1.1 AC-3 Decoder Options</a></li>
</ul></li>
<li><a name="toc-ffwavesynth" href="#ffwavesynth">10.2 ffwavesynth</a></li>
<li><a name="toc-libcelt" href="#libcelt">10.3 libcelt</a></li>
<li><a name="toc-libgsm" href="#libgsm">10.4 libgsm</a></li>
<li><a name="toc-libilbc" href="#libilbc">10.5 libilbc</a>
<ul class="toc">
<li><a name="toc-Options-14" href="#Options-14">10.5.1 Options</a></li>
</ul></li>
<li><a name="toc-libopencore_002damrnb" href="#libopencore_002damrnb">10.6 libopencore-amrnb</a></li>
<li><a name="toc-libopencore_002damrwb" href="#libopencore_002damrwb">10.7 libopencore-amrwb</a></li>
<li><a name="toc-libopus" href="#libopus">10.8 libopus</a></li>
</ul></li>
<li><a name="toc-Subtitles-Decoders" href="#Subtitles-Decoders">11. Subtitles Decoders</a>
<ul class="toc">
<li><a name="toc-dvdsub" href="#dvdsub">11.1 dvdsub</a>
<ul class="toc">
<li><a name="toc-Options-2" href="#Options-2">11.1.1 Options</a></li>
</ul></li>
<li><a name="toc-libzvbi_002dteletext" href="#libzvbi_002dteletext">11.2 libzvbi-teletext</a>
<ul class="toc">
<li><a name="toc-Options-1" href="#Options-1">11.2.1 Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Bitstream-Filters" href="#Bitstream-Filters">12. Bitstream Filters</a>
<ul class="toc">
<li><a name="toc-aac_005fadtstoasc" href="#aac_005fadtstoasc">12.1 aac_adtstoasc</a></li>
<li><a name="toc-chomp" href="#chomp">12.2 chomp</a></li>
<li><a name="toc-dump_005fextra" href="#dump_005fextra">12.3 dump_extra</a></li>
<li><a name="toc-h264_005fmp4toannexb" href="#h264_005fmp4toannexb">12.4 h264_mp4toannexb</a></li>
<li><a name="toc-imx_005fdump_005fheader" href="#imx_005fdump_005fheader">12.5 imx_dump_header</a></li>
<li><a name="toc-mjpeg2jpeg" href="#mjpeg2jpeg">12.6 mjpeg2jpeg</a></li>
<li><a name="toc-mjpega_005fdump_005fheader" href="#mjpega_005fdump_005fheader">12.7 mjpega_dump_header</a></li>
<li><a name="toc-movsub" href="#movsub">12.8 movsub</a></li>
<li><a name="toc-mp3_005fheader_005fdecompress" href="#mp3_005fheader_005fdecompress">12.9 mp3_header_decompress</a></li>
<li><a name="toc-noise-1" href="#noise-1">12.10 noise</a></li>
<li><a name="toc-remove_005fextra" href="#remove_005fextra">12.11 remove_extra</a></li>
</ul></li>
<li><a name="toc-Format-Options" href="#Format-Options">13. Format Options</a>
<ul class="toc">
<li><a name="toc-Format-stream-specifiers-1" href="#Format-stream-specifiers-1">13.1 Format stream specifiers</a></li>
</ul></li>
<li><a name="toc-Demuxers" href="#Demuxers">14. Demuxers</a>
<ul class="toc">
<li><a name="toc-applehttp" href="#applehttp">14.1 applehttp</a></li>
<li><a name="toc-asf" href="#asf">14.2 asf</a></li>
<li><a name="toc-concat-2" href="#concat-2">14.3 concat</a>
<ul class="toc">
<li><a name="toc-Syntax-1" href="#Syntax-1">14.3.1 Syntax</a></li>
<li><a name="toc-Options-13" href="#Options-13">14.3.2 Options</a></li>
</ul></li>
<li><a name="toc-flv" href="#flv">14.4 flv</a></li>
<li><a name="toc-libgme" href="#libgme">14.5 libgme</a></li>
<li><a name="toc-libquvi" href="#libquvi">14.6 libquvi</a></li>
<li><a name="toc-image2" href="#image2">14.7 image2</a>
<ul class="toc">
<li><a name="toc-Examples-78" href="#Examples-78">14.7.1 Examples</a></li>
</ul></li>
<li><a name="toc-mpegts" href="#mpegts">14.8 mpegts</a></li>
<li><a name="toc-rawvideo" href="#rawvideo">14.9 rawvideo</a></li>
<li><a name="toc-sbg" href="#sbg">14.10 sbg</a></li>
<li><a name="toc-tedcaptions" href="#tedcaptions">14.11 tedcaptions</a></li>
</ul></li>
<li><a name="toc-Metadata" href="#Metadata">15. Metadata</a></li>
<li><a name="toc-Protocols" href="#Protocols">16. Protocols</a>
<ul class="toc">
<li><a name="toc-bluray" href="#bluray">16.1 bluray</a></li>
<li><a name="toc-cache" href="#cache">16.2 cache</a></li>
<li><a name="toc-concat-1" href="#concat-1">16.3 concat</a></li>
<li><a name="toc-crypto" href="#crypto">16.4 crypto</a></li>
<li><a name="toc-data" href="#data">16.5 data</a></li>
<li><a name="toc-file" href="#file">16.6 file</a></li>
<li><a name="toc-ftp" href="#ftp">16.7 ftp</a></li>
<li><a name="toc-gopher" href="#gopher">16.8 gopher</a></li>
<li><a name="toc-hls" href="#hls">16.9 hls</a></li>
<li><a name="toc-http" href="#http">16.10 http</a>
<ul class="toc">
<li><a name="toc-HTTP-Cookies" href="#HTTP-Cookies">16.10.1 HTTP Cookies</a></li>
</ul></li>
<li><a name="toc-mmst" href="#mmst">16.11 mmst</a></li>
<li><a name="toc-mmsh" href="#mmsh">16.12 mmsh</a></li>
<li><a name="toc-md5" href="#md5">16.13 md5</a></li>
<li><a name="toc-pipe" href="#pipe">16.14 pipe</a></li>
<li><a name="toc-rtmp" href="#rtmp">16.15 rtmp</a></li>
<li><a name="toc-rtmpe" href="#rtmpe">16.16 rtmpe</a></li>
<li><a name="toc-rtmps" href="#rtmps">16.17 rtmps</a></li>
<li><a name="toc-rtmpt" href="#rtmpt">16.18 rtmpt</a></li>
<li><a name="toc-rtmpte" href="#rtmpte">16.19 rtmpte</a></li>
<li><a name="toc-rtmpts" href="#rtmpts">16.20 rtmpts</a></li>
<li><a name="toc-libssh" href="#libssh">16.21 libssh</a></li>
<li><a name="toc-librtmp-rtmp_002c-rtmpe_002c-rtmps_002c-rtmpt_002c-rtmpte" href="#librtmp-rtmp_002c-rtmpe_002c-rtmps_002c-rtmpt_002c-rtmpte">16.22 librtmp rtmp, rtmpe, rtmps, rtmpt, rtmpte</a></li>
<li><a name="toc-rtp" href="#rtp">16.23 rtp</a></li>
<li><a name="toc-rtsp" href="#rtsp">16.24 rtsp</a>
<ul class="toc">
<li><a name="toc-Examples-4" href="#Examples-4">16.24.1 Examples</a></li>
</ul></li>
<li><a name="toc-sap" href="#sap">16.25 sap</a>
<ul class="toc">
<li><a name="toc-Muxer" href="#Muxer">16.25.1 Muxer</a></li>
<li><a name="toc-Demuxer" href="#Demuxer">16.25.2 Demuxer</a></li>
</ul></li>
<li><a name="toc-sctp" href="#sctp">16.26 sctp</a></li>
<li><a name="toc-srtp" href="#srtp">16.27 srtp</a></li>
<li><a name="toc-subfile" href="#subfile">16.28 subfile</a></li>
<li><a name="toc-tcp" href="#tcp">16.29 tcp</a></li>
<li><a name="toc-tls" href="#tls">16.30 tls</a></li>
<li><a name="toc-udp" href="#udp">16.31 udp</a>
<ul class="toc">
<li><a name="toc-Examples-44" href="#Examples-44">16.31.1 Examples</a></li>
</ul></li>
<li><a name="toc-unix" href="#unix">16.32 unix</a></li>
</ul></li>
<li><a name="toc-Device-Options" href="#Device-Options">17. Device Options</a></li>
<li><a name="toc-Input-Devices" href="#Input-Devices">18. Input Devices</a>
<ul class="toc">
<li><a name="toc-alsa" href="#alsa">18.1 alsa</a></li>
<li><a name="toc-bktr" href="#bktr">18.2 bktr</a></li>
<li><a name="toc-dshow" href="#dshow">18.3 dshow</a>
<ul class="toc">
<li><a name="toc-Options-6" href="#Options-6">18.3.1 Options</a></li>
<li><a name="toc-Examples-28" href="#Examples-28">18.3.2 Examples</a></li>
</ul></li>
<li><a name="toc-dv1394" href="#dv1394">18.4 dv1394</a></li>
<li><a name="toc-fbdev" href="#fbdev">18.5 fbdev</a></li>
<li><a name="toc-gdigrab" href="#gdigrab">18.6 gdigrab</a>
<ul class="toc">
<li><a name="toc-Options-4" href="#Options-4">18.6.1 Options</a></li>
</ul></li>
<li><a name="toc-iec61883" href="#iec61883">18.7 iec61883</a>
<ul class="toc">
<li><a name="toc-Options" href="#Options">18.7.1 Options</a></li>
<li><a name="toc-Examples-62" href="#Examples-62">18.7.2 Examples</a></li>
</ul></li>
<li><a name="toc-jack" href="#jack">18.8 jack</a></li>
<li><a name="toc-lavfi" href="#lavfi">18.9 lavfi</a>
<ul class="toc">
<li><a name="toc-Options-7" href="#Options-7">18.9.1 Options</a></li>
<li><a name="toc-Examples-46" href="#Examples-46">18.9.2 Examples</a></li>
</ul></li>
<li><a name="toc-libdc1394" href="#libdc1394">18.10 libdc1394</a></li>
<li><a name="toc-openal" href="#openal">18.11 openal</a>
<ul class="toc">
<li><a name="toc-Options-8" href="#Options-8">18.11.1 Options</a></li>
<li><a name="toc-Examples-5" href="#Examples-5">18.11.2 Examples</a></li>
</ul></li>
<li><a name="toc-oss" href="#oss">18.12 oss</a></li>
<li><a name="toc-pulse" href="#pulse">18.13 pulse</a>
<ul class="toc">
<li><a name="toc-Options-11" href="#Options-11">18.13.1 Options</a></li>
<li><a name="toc-Examples-61" href="#Examples-61">18.13.2 Examples</a></li>
</ul></li>
<li><a name="toc-qtkit" href="#qtkit">18.14 qtkit</a></li>
<li><a name="toc-sndio" href="#sndio">18.15 sndio</a></li>
<li><a name="toc-video4linux2_002c-v4l2" href="#video4linux2_002c-v4l2">18.16 video4linux2, v4l2</a>
<ul class="toc">
<li><a name="toc-Options-15" href="#Options-15">18.16.1 Options</a></li>
</ul></li>
<li><a name="toc-vfwcap" href="#vfwcap">18.17 vfwcap</a></li>
<li><a name="toc-x11grab" href="#x11grab">18.18 x11grab</a>
<ul class="toc">
<li><a name="toc-Options-3" href="#Options-3">18.18.1 Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Resampler-Options" href="#Resampler-Options">19. Resampler Options</a></li>
<li><a name="toc-Scaler-Options" href="#Scaler-Options">20. Scaler Options</a></li>
<li><a name="toc-Filtering-Introduction" href="#Filtering-Introduction">21. Filtering Introduction</a></li>
<li><a name="toc-graph2dot" href="#graph2dot">22. graph2dot</a></li>
<li><a name="toc-Filtergraph-description" href="#Filtergraph-description">23. Filtergraph description</a>
<ul class="toc">
<li><a name="toc-Filtergraph-syntax-1" href="#Filtergraph-syntax-1">23.1 Filtergraph syntax</a></li>
<li><a name="toc-Notes-on-filtergraph-escaping" href="#Notes-on-filtergraph-escaping">23.2 Notes on filtergraph escaping</a></li>
</ul></li>
<li><a name="toc-Timeline-editing" href="#Timeline-editing">24. Timeline editing</a></li>
<li><a name="toc-Audio-Filters" href="#Audio-Filters">25. Audio Filters</a>
<ul class="toc">
<li><a name="toc-aconvert" href="#aconvert">25.1 aconvert</a>
<ul class="toc">
<li><a name="toc-Examples-66" href="#Examples-66">25.1.1 Examples</a></li>
</ul></li>
<li><a name="toc-adelay" href="#adelay">25.2 adelay</a>
<ul class="toc">
<li><a name="toc-Examples-13" href="#Examples-13">25.2.1 Examples</a></li>
</ul></li>
<li><a name="toc-aecho" href="#aecho">25.3 aecho</a>
<ul class="toc">
<li><a name="toc-Examples-67" href="#Examples-67">25.3.1 Examples</a></li>
</ul></li>
<li><a name="toc-aeval" href="#aeval">25.4 aeval</a>
<ul class="toc">
<li><a name="toc-Examples-77" href="#Examples-77">25.4.1 Examples</a></li>
</ul></li>
<li><a name="toc-afade" href="#afade">25.5 afade</a>
<ul class="toc">
<li><a name="toc-Examples-33" href="#Examples-33">25.5.1 Examples</a></li>
</ul></li>
<li><a name="toc-aformat-1" href="#aformat-1">25.6 aformat</a></li>
<li><a name="toc-allpass" href="#allpass">25.7 allpass</a></li>
<li><a name="toc-amerge" href="#amerge">25.8 amerge</a>
<ul class="toc">
<li><a name="toc-Examples-19" href="#Examples-19">25.8.1 Examples</a></li>
</ul></li>
<li><a name="toc-amix" href="#amix">25.9 amix</a></li>
<li><a name="toc-anull" href="#anull">25.10 anull</a></li>
<li><a name="toc-apad" href="#apad">25.11 apad</a></li>
<li><a name="toc-aphaser" href="#aphaser">25.12 aphaser</a></li>
<li><a name="toc-aresample-1" href="#aresample-1">25.13 aresample</a>
<ul class="toc">
<li><a name="toc-Examples-31" href="#Examples-31">25.13.1 Examples</a></li>
</ul></li>
<li><a name="toc-asetnsamples" href="#asetnsamples">25.14 asetnsamples</a></li>
<li><a name="toc-asetrate" href="#asetrate">25.15 asetrate</a></li>
<li><a name="toc-ashowinfo" href="#ashowinfo">25.16 ashowinfo</a></li>
<li><a name="toc-astats" href="#astats">25.17 astats</a></li>
<li><a name="toc-astreamsync" href="#astreamsync">25.18 astreamsync</a>
<ul class="toc">
<li><a name="toc-Examples" href="#Examples">25.18.1 Examples</a></li>
</ul></li>
<li><a name="toc-asyncts" href="#asyncts">25.19 asyncts</a></li>
<li><a name="toc-atempo" href="#atempo">25.20 atempo</a>
<ul class="toc">
<li><a name="toc-Examples-18" href="#Examples-18">25.20.1 Examples</a></li>
</ul></li>
<li><a name="toc-atrim" href="#atrim">25.21 atrim</a></li>
<li><a name="toc-bandpass" href="#bandpass">25.22 bandpass</a></li>
<li><a name="toc-bandreject" href="#bandreject">25.23 bandreject</a></li>
<li><a name="toc-bass" href="#bass">25.24 bass</a></li>
<li><a name="toc-biquad" href="#biquad">25.25 biquad</a></li>
<li><a name="toc-channelmap" href="#channelmap">25.26 channelmap</a></li>
<li><a name="toc-channelsplit" href="#channelsplit">25.27 channelsplit</a></li>
<li><a name="toc-compand" href="#compand">25.28 compand</a>
<ul class="toc">
<li><a name="toc-Examples-51" href="#Examples-51">25.28.1 Examples</a></li>
</ul></li>
<li><a name="toc-earwax" href="#earwax">25.29 earwax</a></li>
<li><a name="toc-equalizer" href="#equalizer">25.30 equalizer</a>
<ul class="toc">
<li><a name="toc-Examples-26" href="#Examples-26">25.30.1 Examples</a></li>
</ul></li>
<li><a name="toc-highpass" href="#highpass">25.31 highpass</a></li>
<li><a name="toc-join" href="#join">25.32 join</a></li>
<li><a name="toc-ladspa" href="#ladspa">25.33 ladspa</a>
<ul class="toc">
<li><a name="toc-Examples-59" href="#Examples-59">25.33.1 Examples</a></li>
<li><a name="toc-Commands" href="#Commands">25.33.2 Commands</a></li>
</ul></li>
<li><a name="toc-lowpass" href="#lowpass">25.34 lowpass</a></li>
<li><a name="toc-pan" href="#pan">25.35 pan</a>
<ul class="toc">
<li><a name="toc-Mixing-examples" href="#Mixing-examples">25.35.1 Mixing examples</a></li>
<li><a name="toc-Remapping-examples" href="#Remapping-examples">25.35.2 Remapping examples</a></li>
</ul></li>
<li><a name="toc-replaygain" href="#replaygain">25.36 replaygain</a></li>
<li><a name="toc-resample" href="#resample">25.37 resample</a></li>
<li><a name="toc-silencedetect" href="#silencedetect">25.38 silencedetect</a>
<ul class="toc">
<li><a name="toc-Examples-55" href="#Examples-55">25.38.1 Examples</a></li>
</ul></li>
<li><a name="toc-treble" href="#treble">25.39 treble</a></li>
<li><a name="toc-volume" href="#volume">25.40 volume</a>
<ul class="toc">
<li><a name="toc-Commands-4" href="#Commands-4">25.40.1 Commands</a></li>
<li><a name="toc-Examples-30" href="#Examples-30">25.40.2 Examples</a></li>
</ul></li>
<li><a name="toc-volumedetect" href="#volumedetect">25.41 volumedetect</a>
<ul class="toc">
<li><a name="toc-Examples-10" href="#Examples-10">25.41.1 Examples</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Audio-Sources" href="#Audio-Sources">26. Audio Sources</a>
<ul class="toc">
<li><a name="toc-abuffer" href="#abuffer">26.1 abuffer</a>
<ul class="toc">
<li><a name="toc-Examples-9" href="#Examples-9">26.1.1 Examples</a></li>
</ul></li>
<li><a name="toc-aevalsrc" href="#aevalsrc">26.2 aevalsrc</a>
<ul class="toc">
<li><a name="toc-Examples-76" href="#Examples-76">26.2.1 Examples</a></li>
</ul></li>
<li><a name="toc-anullsrc" href="#anullsrc">26.3 anullsrc</a>
<ul class="toc">
<li><a name="toc-Examples-42" href="#Examples-42">26.3.1 Examples</a></li>
</ul></li>
<li><a name="toc-flite" href="#flite">26.4 flite</a>
<ul class="toc">
<li><a name="toc-Examples-56" href="#Examples-56">26.4.1 Examples</a></li>
</ul></li>
<li><a name="toc-sine" href="#sine">26.5 sine</a>
<ul class="toc">
<li><a name="toc-Examples-72" href="#Examples-72">26.5.1 Examples</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Audio-Sinks" href="#Audio-Sinks">27. Audio Sinks</a>
<ul class="toc">
<li><a name="toc-abuffersink" href="#abuffersink">27.1 abuffersink</a></li>
<li><a name="toc-anullsink" href="#anullsink">27.2 anullsink</a></li>
</ul></li>
<li><a name="toc-Video-Filters" href="#Video-Filters">28. Video Filters</a>
<ul class="toc">
<li><a name="toc-alphaextract" href="#alphaextract">28.1 alphaextract</a></li>
<li><a name="toc-alphamerge" href="#alphamerge">28.2 alphamerge</a></li>
<li><a name="toc-ass" href="#ass">28.3 ass</a></li>
<li><a name="toc-bbox" href="#bbox">28.4 bbox</a></li>
<li><a name="toc-blackdetect" href="#blackdetect">28.5 blackdetect</a></li>
<li><a name="toc-blackframe" href="#blackframe">28.6 blackframe</a></li>
<li><a name="toc-blend" href="#blend">28.7 blend</a>
<ul class="toc">
<li><a name="toc-Examples-45" href="#Examples-45">28.7.1 Examples</a></li>
</ul></li>
<li><a name="toc-boxblur" href="#boxblur">28.8 boxblur</a>
<ul class="toc">
<li><a name="toc-Examples-84" href="#Examples-84">28.8.1 Examples</a></li>
</ul></li>
<li><a name="toc-colorbalance" href="#colorbalance">28.9 colorbalance</a>
<ul class="toc">
<li><a name="toc-Examples-23" href="#Examples-23">28.9.1 Examples</a></li>
</ul></li>
<li><a name="toc-colorchannelmixer" href="#colorchannelmixer">28.10 colorchannelmixer</a>
<ul class="toc">
<li><a name="toc-Examples-54" href="#Examples-54">28.10.1 Examples</a></li>
</ul></li>
<li><a name="toc-colormatrix" href="#colormatrix">28.11 colormatrix</a></li>
<li><a name="toc-copy" href="#copy">28.12 copy</a></li>
<li><a name="toc-crop" href="#crop">28.13 crop</a>
<ul class="toc">
<li><a name="toc-Examples-69" href="#Examples-69">28.13.1 Examples</a></li>
</ul></li>
<li><a name="toc-cropdetect" href="#cropdetect">28.14 cropdetect</a></li>
<li><a name="toc-curves-1" href="#curves-1">28.15 curves</a>
<ul class="toc">
<li><a name="toc-Examples-71" href="#Examples-71">28.15.1 Examples</a></li>
</ul></li>
<li><a name="toc-dctdnoiz" href="#dctdnoiz">28.16 dctdnoiz</a>
<ul class="toc">
<li><a name="toc-Examples-21" href="#Examples-21">28.16.1 Examples</a></li>
</ul></li>
<li><a name="toc-decimate-1" href="#decimate-1">28.17 decimate</a></li>
<li><a name="toc-dejudder" href="#dejudder">28.18 dejudder</a></li>
<li><a name="toc-delogo" href="#delogo">28.19 delogo</a>
<ul class="toc">
<li><a name="toc-Examples-49" href="#Examples-49">28.19.1 Examples</a></li>
</ul></li>
<li><a name="toc-deshake" href="#deshake">28.20 deshake</a></li>
<li><a name="toc-drawbox" href="#drawbox">28.21 drawbox</a>
<ul class="toc">
<li><a name="toc-Examples-40" href="#Examples-40">28.21.1 Examples</a></li>
</ul></li>
<li><a name="toc-drawgrid" href="#drawgrid">28.22 drawgrid</a>
<ul class="toc">
<li><a name="toc-Examples-37" href="#Examples-37">28.22.1 Examples</a></li>
</ul></li>
<li><a name="toc-drawtext-1" href="#drawtext-1">28.23 drawtext</a>
<ul class="toc">
<li><a name="toc-Syntax-2" href="#Syntax-2">28.23.1 Syntax</a></li>
<li><a name="toc-Text-expansion" href="#Text-expansion">28.23.2 Text expansion</a></li>
<li><a name="toc-Examples-22" href="#Examples-22">28.23.3 Examples</a></li>
</ul></li>
<li><a name="toc-edgedetect" href="#edgedetect">28.24 edgedetect</a></li>
<li><a name="toc-extractplanes" href="#extractplanes">28.25 extractplanes</a>
<ul class="toc">
<li><a name="toc-Examples-25" href="#Examples-25">28.25.1 Examples</a></li>
</ul></li>
<li><a name="toc-elbg" href="#elbg">28.26 elbg</a></li>
<li><a name="toc-fade" href="#fade">28.27 fade</a>
<ul class="toc">
<li><a name="toc-Examples-68" href="#Examples-68">28.27.1 Examples</a></li>
</ul></li>
<li><a name="toc-field" href="#field">28.28 field</a></li>
<li><a name="toc-fieldmatch" href="#fieldmatch">28.29 fieldmatch</a>
<ul class="toc">
<li><a name="toc-p_002fc_002fn_002fu_002fb-meaning-1" href="#p_002fc_002fn_002fu_002fb-meaning-1">28.29.1 p/c/n/u/b meaning</a>
<ul class="toc">
<li><a name="toc-p_002fc_002fn" href="#p_002fc_002fn">28.29.1.1 p/c/n</a></li>
<li><a name="toc-u_002fb" href="#u_002fb">28.29.1.2 u/b</a></li>
</ul></li>
<li><a name="toc-Examples-57" href="#Examples-57">28.29.2 Examples</a></li>
</ul></li>
<li><a name="toc-fieldorder" href="#fieldorder">28.30 fieldorder</a></li>
<li><a name="toc-fifo" href="#fifo">28.31 fifo</a></li>
<li><a name="toc-format-1" href="#format-1">28.32 format</a>
<ul class="toc">
<li><a name="toc-Examples-20" href="#Examples-20">28.32.1 Examples</a></li>
</ul></li>
<li><a name="toc-fps-1" href="#fps-1">28.33 fps</a>
<ul class="toc">
<li><a name="toc-Examples-32" href="#Examples-32">28.33.1 Examples</a></li>
</ul></li>
<li><a name="toc-framepack" href="#framepack">28.34 framepack</a></li>
<li><a name="toc-framestep" href="#framestep">28.35 framestep</a></li>
<li><a name="toc-frei0r-1" href="#frei0r-1">28.36 frei0r</a>
<ul class="toc">
<li><a name="toc-Examples-6" href="#Examples-6">28.36.1 Examples</a></li>
</ul></li>
<li><a name="toc-geq" href="#geq">28.37 geq</a>
<ul class="toc">
<li><a name="toc-Examples-1" href="#Examples-1">28.37.1 Examples</a></li>
</ul></li>
<li><a name="toc-gradfun" href="#gradfun">28.38 gradfun</a>
<ul class="toc">
<li><a name="toc-Examples-27" href="#Examples-27">28.38.1 Examples</a></li>
</ul></li>
<li><a name="toc-haldclut-1" href="#haldclut-1">28.39 haldclut</a>
<ul class="toc">
<li><a name="toc-Workflow-examples" href="#Workflow-examples">28.39.1 Workflow examples</a>
<ul class="toc">
<li><a name="toc-Hald-CLUT-video-stream" href="#Hald-CLUT-video-stream">28.39.1.1 Hald CLUT video stream</a></li>
<li><a name="toc-Hald-CLUT-with-preview" href="#Hald-CLUT-with-preview">28.39.1.2 Hald CLUT with preview</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-hflip" href="#hflip">28.40 hflip</a></li>
<li><a name="toc-histeq" href="#histeq">28.41 histeq</a></li>
<li><a name="toc-histogram" href="#histogram">28.42 histogram</a>
<ul class="toc">
<li><a name="toc-Examples-3" href="#Examples-3">28.42.1 Examples</a></li>
</ul></li>
<li><a name="toc-hqdn3d-1" href="#hqdn3d-1">28.43 hqdn3d</a></li>
<li><a name="toc-hue" href="#hue">28.44 hue</a>
<ul class="toc">
<li><a name="toc-Examples-24" href="#Examples-24">28.44.1 Examples</a></li>
<li><a name="toc-Commands-1" href="#Commands-1">28.44.2 Commands</a></li>
</ul></li>
<li><a name="toc-idet" href="#idet">28.45 idet</a></li>
<li><a name="toc-il" href="#il">28.46 il</a></li>
<li><a name="toc-interlace" href="#interlace">28.47 interlace</a></li>
<li><a name="toc-kerndeint" href="#kerndeint">28.48 kerndeint</a>
<ul class="toc">
<li><a name="toc-Examples-81" href="#Examples-81">28.48.1 Examples</a></li>
</ul></li>
<li><a name="toc-lut3d-1" href="#lut3d-1">28.49 lut3d</a></li>
<li><a name="toc-lut_002c-lutrgb_002c-lutyuv" href="#lut_002c-lutrgb_002c-lutyuv">28.50 lut, lutrgb, lutyuv</a>
<ul class="toc">
<li><a name="toc-Examples-48" href="#Examples-48">28.50.1 Examples</a></li>
</ul></li>
<li><a name="toc-mergeplanes" href="#mergeplanes">28.51 mergeplanes</a>
<ul class="toc">
<li><a name="toc-Examples-34" href="#Examples-34">28.51.1 Examples</a></li>
</ul></li>
<li><a name="toc-mcdeint" href="#mcdeint">28.52 mcdeint</a></li>
<li><a name="toc-mp" href="#mp">28.53 mp</a>
<ul class="toc">
<li><a name="toc-Examples-58" href="#Examples-58">28.53.1 Examples</a></li>
</ul></li>
<li><a name="toc-mpdecimate" href="#mpdecimate">28.54 mpdecimate</a></li>
<li><a name="toc-negate" href="#negate">28.55 negate</a></li>
<li><a name="toc-noformat" href="#noformat">28.56 noformat</a>
<ul class="toc">
<li><a name="toc-Examples-39" href="#Examples-39">28.56.1 Examples</a></li>
</ul></li>
<li><a name="toc-noise" href="#noise">28.57 noise</a>
<ul class="toc">
<li><a name="toc-Examples-12" href="#Examples-12">28.57.1 Examples</a></li>
</ul></li>
<li><a name="toc-null" href="#null">28.58 null</a></li>
<li><a name="toc-ocv" href="#ocv">28.59 ocv</a>
<ul class="toc">
<li><a name="toc-dilate-1" href="#dilate-1">28.59.1 dilate</a></li>
<li><a name="toc-erode" href="#erode">28.59.2 erode</a></li>
<li><a name="toc-smooth" href="#smooth">28.59.3 smooth</a></li>
</ul></li>
<li><a name="toc-overlay-1" href="#overlay-1">28.60 overlay</a>
<ul class="toc">
<li><a name="toc-Commands-2" href="#Commands-2">28.60.1 Commands</a></li>
<li><a name="toc-Examples-11" href="#Examples-11">28.60.2 Examples</a></li>
</ul></li>
<li><a name="toc-owdenoise" href="#owdenoise">28.61 owdenoise</a></li>
<li><a name="toc-pad" href="#pad">28.62 pad</a>
<ul class="toc">
<li><a name="toc-Examples-36" href="#Examples-36">28.62.1 Examples</a></li>
</ul></li>
<li><a name="toc-perspective" href="#perspective">28.63 perspective</a></li>
<li><a name="toc-phase" href="#phase">28.64 phase</a></li>
<li><a name="toc-pixdesctest" href="#pixdesctest">28.65 pixdesctest</a></li>
<li><a name="toc-pp" href="#pp">28.66 pp</a>
<ul class="toc">
<li><a name="toc-Examples-35" href="#Examples-35">28.66.1 Examples</a></li>
</ul></li>
<li><a name="toc-psnr" href="#psnr">28.67 psnr</a></li>
<li><a name="toc-pullup-1" href="#pullup-1">28.68 pullup</a></li>
<li><a name="toc-removelogo" href="#removelogo">28.69 removelogo</a></li>
<li><a name="toc-rotate" href="#rotate">28.70 rotate</a>
<ul class="toc">
<li><a name="toc-Examples-63" href="#Examples-63">28.70.1 Examples</a></li>
<li><a name="toc-Commands-5" href="#Commands-5">28.70.2 Commands</a></li>
</ul></li>
<li><a name="toc-sab" href="#sab">28.71 sab</a></li>
<li><a name="toc-scale-1" href="#scale-1">28.72 scale</a>
<ul class="toc">
<li><a name="toc-Options-5" href="#Options-5">28.72.1 Options</a></li>
<li><a name="toc-Examples-41" href="#Examples-41">28.72.2 Examples</a></li>
</ul></li>
<li><a name="toc-separatefields" href="#separatefields">28.73 separatefields</a></li>
<li><a name="toc-setdar_002c-setsar" href="#setdar_002c-setsar">28.74 setdar, setsar</a>
<ul class="toc">
<li><a name="toc-Examples-43" href="#Examples-43">28.74.1 Examples</a></li>
</ul></li>
<li><a name="toc-setfield-1" href="#setfield-1">28.75 setfield</a></li>
<li><a name="toc-showinfo" href="#showinfo">28.76 showinfo</a></li>
<li><a name="toc-shuffleplanes" href="#shuffleplanes">28.77 shuffleplanes</a></li>
<li><a name="toc-smartblur-1" href="#smartblur-1">28.78 smartblur</a></li>
<li><a name="toc-stereo3d" href="#stereo3d">28.79 stereo3d</a>
<ul class="toc">
<li><a name="toc-Examples-83" href="#Examples-83">28.79.1 Examples</a></li>
</ul></li>
<li><a name="toc-spp" href="#spp">28.80 spp</a></li>
<li><a name="toc-subtitles-1" href="#subtitles-1">28.81 subtitles</a></li>
<li><a name="toc-super2xsai" href="#super2xsai">28.82 super2xsai</a></li>
<li><a name="toc-swapuv" href="#swapuv">28.83 swapuv</a></li>
<li><a name="toc-telecine" href="#telecine">28.84 telecine</a></li>
<li><a name="toc-thumbnail" href="#thumbnail">28.85 thumbnail</a>
<ul class="toc">
<li><a name="toc-Examples-60" href="#Examples-60">28.85.1 Examples</a></li>
</ul></li>
<li><a name="toc-tile" href="#tile">28.86 tile</a>
<ul class="toc">
<li><a name="toc-Examples-75" href="#Examples-75">28.86.1 Examples</a></li>
</ul></li>
<li><a name="toc-tinterlace" href="#tinterlace">28.87 tinterlace</a></li>
<li><a name="toc-transpose" href="#transpose">28.88 transpose</a></li>
<li><a name="toc-trim" href="#trim">28.89 trim</a></li>
<li><a name="toc-unsharp" href="#unsharp">28.90 unsharp</a>
<ul class="toc">
<li><a name="toc-Examples-15" href="#Examples-15">28.90.1 Examples</a></li>
</ul></li>
<li><a name="toc-vidstabdetect-1" href="#vidstabdetect-1">28.91 vidstabdetect</a>
<ul class="toc">
<li><a name="toc-Examples-64" href="#Examples-64">28.91.1 Examples</a></li>
</ul></li>
<li><a name="toc-vidstabtransform-1" href="#vidstabtransform-1">28.92 vidstabtransform</a>
<ul class="toc">
<li><a name="toc-Options-10" href="#Options-10">28.92.1 Options</a></li>
<li><a name="toc-Examples-14" href="#Examples-14">28.92.2 Examples</a></li>
</ul></li>
<li><a name="toc-vflip" href="#vflip">28.93 vflip</a></li>
<li><a name="toc-vignette" href="#vignette">28.94 vignette</a>
<ul class="toc">
<li><a name="toc-Expressions" href="#Expressions">28.94.1 Expressions</a></li>
<li><a name="toc-Examples-80" href="#Examples-80">28.94.2 Examples</a></li>
</ul></li>
<li><a name="toc-w3fdif" href="#w3fdif">28.95 w3fdif</a></li>
<li><a name="toc-yadif-1" href="#yadif-1">28.96 yadif</a></li>
</ul></li>
<li><a name="toc-Video-Sources" href="#Video-Sources">29. Video Sources</a>
<ul class="toc">
<li><a name="toc-buffer" href="#buffer">29.1 buffer</a></li>
<li><a name="toc-cellauto" href="#cellauto">29.2 cellauto</a>
<ul class="toc">
<li><a name="toc-Examples-38" href="#Examples-38">29.2.1 Examples</a></li>
</ul></li>
<li><a name="toc-mandelbrot" href="#mandelbrot">29.3 mandelbrot</a></li>
<li><a name="toc-mptestsrc" href="#mptestsrc">29.4 mptestsrc</a></li>
<li><a name="toc-frei0r_005fsrc" href="#frei0r_005fsrc">29.5 frei0r_src</a></li>
<li><a name="toc-life" href="#life">29.6 life</a>
<ul class="toc">
<li><a name="toc-Examples-50" href="#Examples-50">29.6.1 Examples</a></li>
</ul></li>
<li><a name="toc-color_002c-haldclutsrc_002c-nullsrc_002c-rgbtestsrc_002c-smptebars_002c-smptehdbars_002c-testsrc" href="#color_002c-haldclutsrc_002c-nullsrc_002c-rgbtestsrc_002c-smptebars_002c-smptehdbars_002c-testsrc">29.7 color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc</a>
<ul class="toc">
<li><a name="toc-Commands-3" href="#Commands-3">29.7.1 Commands</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Video-Sinks" href="#Video-Sinks">30. Video Sinks</a>
<ul class="toc">
<li><a name="toc-buffersink" href="#buffersink">30.1 buffersink</a></li>
<li><a name="toc-nullsink" href="#nullsink">30.2 nullsink</a></li>
</ul></li>
<li><a name="toc-Multimedia-Filters" href="#Multimedia-Filters">31. Multimedia Filters</a>
<ul class="toc">
<li><a name="toc-avectorscope" href="#avectorscope">31.1 avectorscope</a>
<ul class="toc">
<li><a name="toc-Examples-73" href="#Examples-73">31.1.1 Examples</a></li>
</ul></li>
<li><a name="toc-concat-3" href="#concat-3">31.2 concat</a>
<ul class="toc">
<li><a name="toc-Examples-53" href="#Examples-53">31.2.1 Examples</a></li>
</ul></li>
<li><a name="toc-ebur128" href="#ebur128">31.3 ebur128</a>
<ul class="toc">
<li><a name="toc-Examples-70" href="#Examples-70">31.3.1 Examples</a></li>
</ul></li>
<li><a name="toc-interleave_002c-ainterleave" href="#interleave_002c-ainterleave">31.4 interleave, ainterleave</a>
<ul class="toc">
<li><a name="toc-Examples-2" href="#Examples-2">31.4.1 Examples</a></li>
</ul></li>
<li><a name="toc-perms_002c-aperms" href="#perms_002c-aperms">31.5 perms, aperms</a></li>
<li><a name="toc-select_002c-aselect" href="#select_002c-aselect">31.6 select, aselect</a>
<ul class="toc">
<li><a name="toc-Examples-29" href="#Examples-29">31.6.1 Examples</a></li>
</ul></li>
<li><a name="toc-sendcmd_002c-asendcmd" href="#sendcmd_002c-asendcmd">31.7 sendcmd, asendcmd</a>
<ul class="toc">
<li><a name="toc-Commands-syntax" href="#Commands-syntax">31.7.1 Commands syntax</a></li>
<li><a name="toc-Examples-47" href="#Examples-47">31.7.2 Examples</a></li>
</ul></li>
<li><a name="toc-setpts_002c-asetpts" href="#setpts_002c-asetpts">31.8 setpts, asetpts</a>
<ul class="toc">
<li><a name="toc-Examples-16" href="#Examples-16">31.8.1 Examples</a></li>
</ul></li>
<li><a name="toc-settb_002c-asettb" href="#settb_002c-asettb">31.9 settb, asettb</a>
<ul class="toc">
<li><a name="toc-Examples-8" href="#Examples-8">31.9.1 Examples</a></li>
</ul></li>
<li><a name="toc-showspectrum" href="#showspectrum">31.10 showspectrum</a>
<ul class="toc">
<li><a name="toc-Examples-74" href="#Examples-74">31.10.1 Examples</a></li>
</ul></li>
<li><a name="toc-showwaves" href="#showwaves">31.11 showwaves</a>
<ul class="toc">
<li><a name="toc-Examples-52" href="#Examples-52">31.11.1 Examples</a></li>
</ul></li>
<li><a name="toc-split_002c-asplit" href="#split_002c-asplit">31.12 split, asplit</a>
<ul class="toc">
<li><a name="toc-Examples-7" href="#Examples-7">31.12.1 Examples</a></li>
</ul></li>
<li><a name="toc-zmq_002c-azmq" href="#zmq_002c-azmq">31.13 zmq, azmq</a>
<ul class="toc">
<li><a name="toc-Examples-82" href="#Examples-82">31.13.1 Examples</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Multimedia-Sources" href="#Multimedia-Sources">32. Multimedia Sources</a>
<ul class="toc">
<li><a name="toc-amovie" href="#amovie">32.1 amovie</a></li>
<li><a name="toc-movie-1" href="#movie-1">32.2 movie</a>
<ul class="toc">
<li><a name="toc-Examples-17" href="#Examples-17">32.2.1 Examples</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-See-Also" href="#See-Also">33. See Also</a></li>
<li><a name="toc-Authors" href="#Authors">34. Authors</a></li>
</ul>
</div>
<a name="Synopsis"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Synopsis">1. Synopsis</a></h1>
<p>ffplay [<var>options</var>] [&lsquo;<tt>input_file</tt>&rsquo;]
</p>
<a name="Description"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Description">2. Description</a></h1>
<p>FFplay is a very simple and portable media player using the FFmpeg
libraries and the SDL library. It is mostly used as a testbed for the
various FFmpeg APIs.
</p>
<a name="Options-9"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Options-9">3. Options</a></h1>
<p>All the numerical options, if not specified otherwise, accept a string
representing a number as input, which may be followed by one of the SI
unit prefixes, for example: &rsquo;K&rsquo;, &rsquo;M&rsquo;, or &rsquo;G&rsquo;.
</p>
<p>If &rsquo;i&rsquo; is appended to the SI unit prefix, the complete prefix will be
interpreted as a unit prefix for binary multiplies, which are based on
powers of 1024 instead of powers of 1000. Appending &rsquo;B&rsquo; to the SI unit
prefix multiplies the value by 8. This allows using, for example:
&rsquo;KB&rsquo;, &rsquo;MiB&rsquo;, &rsquo;G&rsquo; and &rsquo;B&rsquo; as number suffixes.
</p>
<p>Options which do not take arguments are boolean options, and set the
corresponding value to true. They can be set to false by prefixing
the option name with &quot;no&quot;. For example using &quot;-nofoo&quot;
will set the boolean option with name &quot;foo&quot; to false.
</p>
<p><a name="Stream-specifiers"></a>
</p><a name="Stream-specifiers-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Stream-specifiers-1">3.1 Stream specifiers</a></h2>
<p>Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers
are used to precisely specify which stream(s) a given option belongs to.
</p>
<p>A stream specifier is a string generally appended to the option name and
separated from it by a colon. E.g. <code>-codec:a:1 ac3</code> contains the
<code>a:1</code> stream specifier, which matches the second audio stream. Therefore, it
would select the ac3 codec for the second audio stream.
</p>
<p>A stream specifier can match several streams, so that the option is applied to all
of them. E.g. the stream specifier in <code>-b:a 128k</code> matches all audio
streams.
</p>
<p>An empty stream specifier matches all streams. For example, <code>-codec copy</code>
or <code>-codec: copy</code> would copy all the streams without reencoding.
</p>
<p>Possible forms of stream specifiers are:
</p><dl compact="compact">
<dt> &lsquo;<samp><var>stream_index</var></samp>&rsquo;</dt>
<dd><p>Matches the stream with this index. E.g. <code>-threads:1 4</code> would set the
thread count for the second stream to 4.
</p></dd>
<dt> &lsquo;<samp><var>stream_type</var>[:<var>stream_index</var>]</samp>&rsquo;</dt>
<dd><p><var>stream_type</var> is one of following: &rsquo;v&rsquo; for video, &rsquo;a&rsquo; for audio, &rsquo;s&rsquo; for subtitle,
&rsquo;d&rsquo; for data, and &rsquo;t&rsquo; for attachments. If <var>stream_index</var> is given, then it matches
stream number <var>stream_index</var> of this type. Otherwise, it matches all
streams of this type.
</p></dd>
<dt> &lsquo;<samp>p:<var>program_id</var>[:<var>stream_index</var>]</samp>&rsquo;</dt>
<dd><p>If <var>stream_index</var> is given, then it matches the stream with number <var>stream_index</var>
in the program with the id <var>program_id</var>. Otherwise, it matches all streams in the
program.
</p></dd>
<dt> &lsquo;<samp>#<var>stream_id</var> or i:<var>stream_id</var></samp>&rsquo;</dt>
<dd><p>Match the stream by stream id (e.g. PID in MPEG-TS container).
</p></dd>
</dl>
<a name="Generic-options"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Generic-options">3.2 Generic options</a></h2>
<p>These options are shared amongst the ff* tools.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>-L</samp>&rsquo;</dt>
<dd><p>Show license.
</p>
</dd>
<dt> &lsquo;<samp>-h, -?, -help, --help [<var>arg</var>]</samp>&rsquo;</dt>
<dd><p>Show help. An optional parameter may be specified to print help about a specific
item. If no argument is specified, only basic (non advanced) tool
options are shown.
</p>
<p>Possible values of <var>arg</var> are:
</p><dl compact="compact">
<dt> &lsquo;<samp>long</samp>&rsquo;</dt>
<dd><p>Print advanced tool options in addition to the basic tool options.
</p>
</dd>
<dt> &lsquo;<samp>full</samp>&rsquo;</dt>
<dd><p>Print complete list of options, including shared and private options
for encoders, decoders, demuxers, muxers, filters, etc.
</p>
</dd>
<dt> &lsquo;<samp>decoder=<var>decoder_name</var></samp>&rsquo;</dt>
<dd><p>Print detailed information about the decoder named <var>decoder_name</var>. Use the
&lsquo;<samp>-decoders</samp>&rsquo; option to get a list of all decoders.
</p>
</dd>
<dt> &lsquo;<samp>encoder=<var>encoder_name</var></samp>&rsquo;</dt>
<dd><p>Print detailed information about the encoder named <var>encoder_name</var>. Use the
&lsquo;<samp>-encoders</samp>&rsquo; option to get a list of all encoders.
</p>
</dd>
<dt> &lsquo;<samp>demuxer=<var>demuxer_name</var></samp>&rsquo;</dt>
<dd><p>Print detailed information about the demuxer named <var>demuxer_name</var>. Use the
&lsquo;<samp>-formats</samp>&rsquo; option to get a list of all demuxers and muxers.
</p>
</dd>
<dt> &lsquo;<samp>muxer=<var>muxer_name</var></samp>&rsquo;</dt>
<dd><p>Print detailed information about the muxer named <var>muxer_name</var>. Use the
&lsquo;<samp>-formats</samp>&rsquo; option to get a list of all muxers and demuxers.
</p>
</dd>
<dt> &lsquo;<samp>filter=<var>filter_name</var></samp>&rsquo;</dt>
<dd><p>Print detailed information about the filter name <var>filter_name</var>. Use the
&lsquo;<samp>-filters</samp>&rsquo; option to get a list of all filters.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>-version</samp>&rsquo;</dt>
<dd><p>Show version.
</p>
</dd>
<dt> &lsquo;<samp>-formats</samp>&rsquo;</dt>
<dd><p>Show available formats.
</p>
</dd>
<dt> &lsquo;<samp>-codecs</samp>&rsquo;</dt>
<dd><p>Show all codecs known to libavcodec.
</p>
<p>Note that the term &rsquo;codec&rsquo; is used throughout this documentation as a shortcut
for what is more correctly called a media bitstream format.
</p>
</dd>
<dt> &lsquo;<samp>-decoders</samp>&rsquo;</dt>
<dd><p>Show available decoders.
</p>
</dd>
<dt> &lsquo;<samp>-encoders</samp>&rsquo;</dt>
<dd><p>Show all available encoders.
</p>
</dd>
<dt> &lsquo;<samp>-bsfs</samp>&rsquo;</dt>
<dd><p>Show available bitstream filters.
</p>
</dd>
<dt> &lsquo;<samp>-protocols</samp>&rsquo;</dt>
<dd><p>Show available protocols.
</p>
</dd>
<dt> &lsquo;<samp>-filters</samp>&rsquo;</dt>
<dd><p>Show available libavfilter filters.
</p>
</dd>
<dt> &lsquo;<samp>-pix_fmts</samp>&rsquo;</dt>
<dd><p>Show available pixel formats.
</p>
</dd>
<dt> &lsquo;<samp>-sample_fmts</samp>&rsquo;</dt>
<dd><p>Show available sample formats.
</p>
</dd>
<dt> &lsquo;<samp>-layouts</samp>&rsquo;</dt>
<dd><p>Show channel names and standard channel layouts.
</p>
</dd>
<dt> &lsquo;<samp>-colors</samp>&rsquo;</dt>
<dd><p>Show recognized color names.
</p>
</dd>
<dt> &lsquo;<samp>-loglevel [repeat+]<var>loglevel</var> | -v [repeat+]<var>loglevel</var></samp>&rsquo;</dt>
<dd><p>Set the logging level used by the library.
Adding &quot;repeat+&quot; indicates that repeated log output should not be compressed
to the first line and the &quot;Last message repeated n times&quot; line will be
omitted. &quot;repeat&quot; can also be used alone.
If &quot;repeat&quot; is used alone, and with no prior loglevel set, the default
loglevel will be used. If multiple loglevel parameters are given, using
&rsquo;repeat&rsquo; will not change the loglevel.
<var>loglevel</var> is a number or a string containing one of the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>quiet</samp>&rsquo;</dt>
<dd><p>Show nothing at all; be silent.
</p></dd>
<dt> &lsquo;<samp>panic</samp>&rsquo;</dt>
<dd><p>Only show fatal errors which could lead the process to crash, such as
and assert failure. This is not currently used for anything.
</p></dd>
<dt> &lsquo;<samp>fatal</samp>&rsquo;</dt>
<dd><p>Only show fatal errors. These are errors after which the process absolutely
cannot continue after.
</p></dd>
<dt> &lsquo;<samp>error</samp>&rsquo;</dt>
<dd><p>Show all errors, including ones which can be recovered from.
</p></dd>
<dt> &lsquo;<samp>warning</samp>&rsquo;</dt>
<dd><p>Show all warnings and errors. Any message related to possibly
incorrect or unexpected events will be shown.
</p></dd>
<dt> &lsquo;<samp>info</samp>&rsquo;</dt>
<dd><p>Show informative messages during processing. This is in addition to
warnings and errors. This is the default value.
</p></dd>
<dt> &lsquo;<samp>verbose</samp>&rsquo;</dt>
<dd><p>Same as <code>info</code>, except more verbose.
</p></dd>
<dt> &lsquo;<samp>debug</samp>&rsquo;</dt>
<dd><p>Show everything, including debugging information.
</p></dd>
</dl>
<p>By default the program logs to stderr, if coloring is supported by the
terminal, colors are used to mark errors and warnings. Log coloring
can be disabled setting the environment variable
<code>AV_LOG_FORCE_NOCOLOR</code> or <code>NO_COLOR</code>, or can be forced setting
the environment variable <code>AV_LOG_FORCE_COLOR</code>.
The use of the environment variable <code>NO_COLOR</code> is deprecated and
will be dropped in a following FFmpeg version.
</p>
</dd>
<dt> &lsquo;<samp>-report</samp>&rsquo;</dt>
<dd><p>Dump full command line and console output to a file named
<code><var>program</var>-<var>YYYYMMDD</var>-<var>HHMMSS</var>.log</code> in the current
directory.
This file can be useful for bug reports.
It also implies <code>-loglevel verbose</code>.
</p>
<p>Setting the environment variable <code>FFREPORT</code> to any value has the
same effect. If the value is a &rsquo;:&rsquo;-separated key=value sequence, these
options will affect the report; options values must be escaped if they
contain special characters or the options delimiter &rsquo;:&rsquo; (see the
&ldquo;Quoting and escaping&rdquo; section in the ffmpeg-utils manual). The
following option is recognized:
</p><dl compact="compact">
<dt> &lsquo;<samp>file</samp>&rsquo;</dt>
<dd><p>set the file name to use for the report; <code>%p</code> is expanded to the name
of the program, <code>%t</code> is expanded to a timestamp, <code>%%</code> is expanded
to a plain <code>%</code>
</p></dd>
</dl>
<p>Errors in parsing the environment variable are not fatal, and will not
appear in the report.
</p>
</dd>
<dt> &lsquo;<samp>-hide_banner</samp>&rsquo;</dt>
<dd><p>Suppress printing banner.
</p>
<p>All FFmpeg tools will normally show a copyright notice, build options
and library versions. This option can be used to suppress printing
this information.
</p>
</dd>
<dt> &lsquo;<samp>-cpuflags flags (<em>global</em>)</samp>&rsquo;</dt>
<dd><p>Allows setting and clearing cpu flags. This option is intended
for testing. Do not use it unless you know what you&rsquo;re doing.
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -cpuflags -sse+mmx ...
ffmpeg -cpuflags mmx ...
ffmpeg -cpuflags 0 ...
</pre></td></tr></table>
<p>Possible flags for this option are:
</p><dl compact="compact">
<dt> &lsquo;<samp>x86</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>mmx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>mmxext</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse2slow</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse3</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse3slow</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ssse3</samp>&rsquo;</dt>
<dt> &lsquo;<samp>atom</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse4.1</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sse4.2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>avx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>xop</samp>&rsquo;</dt>
<dt> &lsquo;<samp>fma4</samp>&rsquo;</dt>
<dt> &lsquo;<samp>3dnow</samp>&rsquo;</dt>
<dt> &lsquo;<samp>3dnowext</samp>&rsquo;</dt>
<dt> &lsquo;<samp>cmov</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>ARM</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>armv5te</samp>&rsquo;</dt>
<dt> &lsquo;<samp>armv6</samp>&rsquo;</dt>
<dt> &lsquo;<samp>armv6t2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vfp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vfpv3</samp>&rsquo;</dt>
<dt> &lsquo;<samp>neon</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>PowerPC</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>altivec</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>Specific Processors</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>pentium2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>pentium3</samp>&rsquo;</dt>
<dt> &lsquo;<samp>pentium4</samp>&rsquo;</dt>
<dt> &lsquo;<samp>k6</samp>&rsquo;</dt>
<dt> &lsquo;<samp>k62</samp>&rsquo;</dt>
<dt> &lsquo;<samp>athlon</samp>&rsquo;</dt>
<dt> &lsquo;<samp>athlonxp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>k8</samp>&rsquo;</dt>
</dl>
</dd>
</dl>
</dd>
<dt> &lsquo;<samp>-opencl_bench</samp>&rsquo;</dt>
<dd><p>Benchmark all available OpenCL devices and show the results. This option
is only available when FFmpeg has been compiled with <code>--enable-opencl</code>.
</p>
</dd>
<dt> &lsquo;<samp>-opencl_options options (<em>global</em>)</samp>&rsquo;</dt>
<dd><p>Set OpenCL environment options. This option is only available when
FFmpeg has been compiled with <code>--enable-opencl</code>.
</p>
<p><var>options</var> must be a list of <var>key</var>=<var>value</var> option pairs
separated by &rsquo;:&rsquo;. See the &ldquo;OpenCL Options&rdquo; section in the
ffmpeg-utils manual for the list of supported options.
</p></dd>
</dl>
<a name="AVOptions"></a>
<h2 class="section"><a href="ffplay-all.html#toc-AVOptions">3.3 AVOptions</a></h2>
<p>These options are provided directly by the libavformat, libavdevice and
libavcodec libraries. To see the list of available AVOptions, use the
&lsquo;<samp>-help</samp>&rsquo; option. They are separated into two categories:
</p><dl compact="compact">
<dt> &lsquo;<samp>generic</samp>&rsquo;</dt>
<dd><p>These options can be set for any container, codec or device. Generic options
are listed under AVFormatContext options for containers/devices and under
AVCodecContext options for codecs.
</p></dd>
<dt> &lsquo;<samp>private</samp>&rsquo;</dt>
<dd><p>These options are specific to the given container, device or codec. Private
options are listed under their corresponding containers/devices/codecs.
</p></dd>
</dl>
<p>For example to write an ID3v2.3 header instead of a default ID3v2.4 to
an MP3 file, use the &lsquo;<samp>id3v2_version</samp>&rsquo; private option of the MP3
muxer:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i input.flac -id3v2_version 3 out.mp3
</pre></td></tr></table>
<p>All codec AVOptions are per-stream, and thus a stream specifier
should be attached to them.
</p>
<p>Note: the &lsquo;<samp>-nooption</samp>&rsquo; syntax cannot be used for boolean
AVOptions, use &lsquo;<samp>-option 0</samp>&rsquo;/&lsquo;<samp>-option 1</samp>&rsquo;.
</p>
<p>Note: the old undocumented way of specifying per-stream AVOptions by
prepending v/a/s to the options name is now obsolete and will be
removed soon.
</p>
<a name="Main-options"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Main-options">3.4 Main options</a></h2>
<dl compact="compact">
<dt> &lsquo;<samp>-x <var>width</var></samp>&rsquo;</dt>
<dd><p>Force displayed width.
</p></dd>
<dt> &lsquo;<samp>-y <var>height</var></samp>&rsquo;</dt>
<dd><p>Force displayed height.
</p></dd>
<dt> &lsquo;<samp>-s <var>size</var></samp>&rsquo;</dt>
<dd><p>Set frame size (WxH or abbreviation), needed for videos which do
not contain a header with the frame size like raw YUV. This option
has been deprecated in favor of private options, try -video_size.
</p></dd>
<dt> &lsquo;<samp>-an</samp>&rsquo;</dt>
<dd><p>Disable audio.
</p></dd>
<dt> &lsquo;<samp>-vn</samp>&rsquo;</dt>
<dd><p>Disable video.
</p></dd>
<dt> &lsquo;<samp>-ss <var>pos</var></samp>&rsquo;</dt>
<dd><p>Seek to a given position in seconds.
</p></dd>
<dt> &lsquo;<samp>-t <var>duration</var></samp>&rsquo;</dt>
<dd><p>play &lt;duration&gt; seconds of audio/video
</p></dd>
<dt> &lsquo;<samp>-bytes</samp>&rsquo;</dt>
<dd><p>Seek by bytes.
</p></dd>
<dt> &lsquo;<samp>-nodisp</samp>&rsquo;</dt>
<dd><p>Disable graphical display.
</p></dd>
<dt> &lsquo;<samp>-f <var>fmt</var></samp>&rsquo;</dt>
<dd><p>Force format.
</p></dd>
<dt> &lsquo;<samp>-window_title <var>title</var></samp>&rsquo;</dt>
<dd><p>Set window title (default is the input filename).
</p></dd>
<dt> &lsquo;<samp>-loop <var>number</var></samp>&rsquo;</dt>
<dd><p>Loops movie playback &lt;number&gt; times. 0 means forever.
</p></dd>
<dt> &lsquo;<samp>-showmode <var>mode</var></samp>&rsquo;</dt>
<dd><p>Set the show mode to use.
Available values for <var>mode</var> are:
</p><dl compact="compact">
<dt> &lsquo;<samp>0, video</samp>&rsquo;</dt>
<dd><p>show video
</p></dd>
<dt> &lsquo;<samp>1, waves</samp>&rsquo;</dt>
<dd><p>show audio waves
</p></dd>
<dt> &lsquo;<samp>2, rdft</samp>&rsquo;</dt>
<dd><p>show audio frequency band using RDFT ((Inverse) Real Discrete Fourier Transform)
</p></dd>
</dl>
<p>Default value is &quot;video&quot;, if video is not present or cannot be played
&quot;rdft&quot; is automatically selected.
</p>
<p>You can interactively cycle through the available show modes by
pressing the key &lt;w&gt;.
</p>
</dd>
<dt> &lsquo;<samp>-vf <var>filtergraph</var></samp>&rsquo;</dt>
<dd><p>Create the filtergraph specified by <var>filtergraph</var> and use it to
filter the video stream.
</p>
<p><var>filtergraph</var> is a description of the filtergraph to apply to
the stream, and must have a single video input and a single video
output. In the filtergraph, the input is associated to the label
<code>in</code>, and the output to the label <code>out</code>. See the
ffmpeg-filters manual for more information about the filtergraph
syntax.
</p>
</dd>
<dt> &lsquo;<samp>-af <var>filtergraph</var></samp>&rsquo;</dt>
<dd><p><var>filtergraph</var> is a description of the filtergraph to apply to
the input audio.
Use the option &quot;-filters&quot; to show all the available filters (including
sources and sinks).
</p>
</dd>
<dt> &lsquo;<samp>-i <var>input_file</var></samp>&rsquo;</dt>
<dd><p>Read <var>input_file</var>.
</p></dd>
</dl>
<a name="Advanced-options"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Advanced-options">3.5 Advanced options</a></h2>
<dl compact="compact">
<dt> &lsquo;<samp>-pix_fmt <var>format</var></samp>&rsquo;</dt>
<dd><p>Set pixel format.
This option has been deprecated in favor of private options, try -pixel_format.
</p>
</dd>
<dt> &lsquo;<samp>-stats</samp>&rsquo;</dt>
<dd><p>Print several playback statistics, in particular show the stream
duration, the codec parameters, the current position in the stream and
the audio/video synchronisation drift. It is on by default, to
explicitly disable it you need to specify <code>-nostats</code>.
</p>
</dd>
<dt> &lsquo;<samp>-bug</samp>&rsquo;</dt>
<dd><p>Work around bugs.
</p></dd>
<dt> &lsquo;<samp>-fast</samp>&rsquo;</dt>
<dd><p>Non-spec-compliant optimizations.
</p></dd>
<dt> &lsquo;<samp>-genpts</samp>&rsquo;</dt>
<dd><p>Generate pts.
</p></dd>
<dt> &lsquo;<samp>-rtp_tcp</samp>&rsquo;</dt>
<dd><p>Force RTP/TCP protocol usage instead of RTP/UDP. It is only meaningful
if you are streaming with the RTSP protocol.
</p></dd>
<dt> &lsquo;<samp>-sync <var>type</var></samp>&rsquo;</dt>
<dd><p>Set the master clock to audio (<code>type=audio</code>), video
(<code>type=video</code>) or external (<code>type=ext</code>). Default is audio. The
master clock is used to control audio-video synchronization. Most media
players use audio as master clock, but in some cases (streaming or high
quality broadcast) it is necessary to change that. This option is mainly
used for debugging purposes.
</p></dd>
<dt> &lsquo;<samp>-threads <var>count</var></samp>&rsquo;</dt>
<dd><p>Set the thread count.
</p></dd>
<dt> &lsquo;<samp>-ast <var>audio_stream_number</var></samp>&rsquo;</dt>
<dd><p>Select the desired audio stream number, counting from 0. The number
refers to the list of all the input audio streams. If it is greater
than the number of audio streams minus one, then the last one is
selected, if it is negative the audio playback is disabled.
</p></dd>
<dt> &lsquo;<samp>-vst <var>video_stream_number</var></samp>&rsquo;</dt>
<dd><p>Select the desired video stream number, counting from 0. The number
refers to the list of all the input video streams. If it is greater
than the number of video streams minus one, then the last one is
selected, if it is negative the video playback is disabled.
</p></dd>
<dt> &lsquo;<samp>-sst <var>subtitle_stream_number</var></samp>&rsquo;</dt>
<dd><p>Select the desired subtitle stream number, counting from 0. The number
refers to the list of all the input subtitle streams. If it is greater
than the number of subtitle streams minus one, then the last one is
selected, if it is negative the subtitle rendering is disabled.
</p></dd>
<dt> &lsquo;<samp>-autoexit</samp>&rsquo;</dt>
<dd><p>Exit when video is done playing.
</p></dd>
<dt> &lsquo;<samp>-exitonkeydown</samp>&rsquo;</dt>
<dd><p>Exit if any key is pressed.
</p></dd>
<dt> &lsquo;<samp>-exitonmousedown</samp>&rsquo;</dt>
<dd><p>Exit if any mouse button is pressed.
</p>
</dd>
<dt> &lsquo;<samp>-codec:<var>media_specifier</var> <var>codec_name</var></samp>&rsquo;</dt>
<dd><p>Force a specific decoder implementation for the stream identified by
<var>media_specifier</var>, which can assume the values <code>a</code> (audio),
<code>v</code> (video), and <code>s</code> subtitle.
</p>
</dd>
<dt> &lsquo;<samp>-acodec <var>codec_name</var></samp>&rsquo;</dt>
<dd><p>Force a specific audio decoder.
</p>
</dd>
<dt> &lsquo;<samp>-vcodec <var>codec_name</var></samp>&rsquo;</dt>
<dd><p>Force a specific video decoder.
</p>
</dd>
<dt> &lsquo;<samp>-scodec <var>codec_name</var></samp>&rsquo;</dt>
<dd><p>Force a specific subtitle decoder.
</p></dd>
</dl>
<a name="While-playing"></a>
<h2 class="section"><a href="ffplay-all.html#toc-While-playing">3.6 While playing</a></h2>
<dl compact="compact">
<dt> &lt;q, ESC&gt;</dt>
<dd><p>Quit.
</p>
</dd>
<dt> &lt;f&gt;</dt>
<dd><p>Toggle full screen.
</p>
</dd>
<dt> &lt;p, SPC&gt;</dt>
<dd><p>Pause.
</p>
</dd>
<dt> &lt;a&gt;</dt>
<dd><p>Cycle audio channel in the curret program.
</p>
</dd>
<dt> &lt;v&gt;</dt>
<dd><p>Cycle video channel.
</p>
</dd>
<dt> &lt;t&gt;</dt>
<dd><p>Cycle subtitle channel in the current program.
</p>
</dd>
<dt> &lt;c&gt;</dt>
<dd><p>Cycle program.
</p>
</dd>
<dt> &lt;w&gt;</dt>
<dd><p>Show audio waves.
</p>
</dd>
<dt> &lt;s&gt;</dt>
<dd><p>Step to the next frame.
</p>
<p>Pause if the stream is not already paused, step to the next video
frame, and pause.
</p>
</dd>
<dt> &lt;left/right&gt;</dt>
<dd><p>Seek backward/forward 10 seconds.
</p>
</dd>
<dt> &lt;down/up&gt;</dt>
<dd><p>Seek backward/forward 1 minute.
</p>
</dd>
<dt> &lt;page down/page up&gt;</dt>
<dd><p>Seek to the previous/next chapter.
or if there are no chapters
Seek backward/forward 10 minutes.
</p>
</dd>
<dt> &lt;mouse click&gt;</dt>
<dd><p>Seek to percentage in file corresponding to fraction of width.
</p>
</dd>
</dl>
<a name="Syntax"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Syntax">4. Syntax</a></h1>
<p>This section documents the syntax and formats employed by the FFmpeg
libraries and tools.
</p>
<p><a name="quoting_005fand_005fescaping"></a>
</p><a name="Quoting-and-escaping"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Quoting-and-escaping">4.1 Quoting and escaping</a></h2>
<p>FFmpeg adopts the following quoting and escaping mechanism, unless
explicitly specified. The following rules are applied:
</p>
<ul>
<li>
<code>'</code> and <code>\</code> are special characters (respectively used for
quoting and escaping). In addition to them, there might be other
special characters depending on the specific syntax where the escaping
and quoting are employed.
</li><li>
A special character is escaped by prefixing it with a &rsquo;\&rsquo;.
</li><li>
All characters enclosed between &rdquo; are included literally in the
parsed string. The quote character <code>'</code> itself cannot be quoted,
so you may need to close the quote and escape it.
</li><li>
Leading and trailing whitespaces, unless escaped or quoted, are
removed from the parsed string.
</li></ul>
<p>Note that you may need to add a second level of escaping when using
the command line or a script, which depends on the syntax of the
adopted shell language.
</p>
<p>The function <code>av_get_token</code> defined in
&lsquo;<tt>libavutil/avstring.h</tt>&rsquo; can be used to parse a token quoted or
escaped according to the rules defined above.
</p>
<p>The tool &lsquo;<tt>tools/ffescape</tt>&rsquo; in the FFmpeg source tree can be used
to automatically quote or escape a string in a script.
</p>
<a name="Examples-79"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-79">4.1.1 Examples</a></h3>
<ul>
<li>
Escape the string <code>Crime d'Amour</code> containing the <code>'</code> special
character:
<table><tr><td>&nbsp;</td><td><pre class="example">Crime d\'Amour
</pre></td></tr></table>
</li><li>
The string above contains a quote, so the <code>'</code> needs to be escaped
when quoting it:
<table><tr><td>&nbsp;</td><td><pre class="example">'Crime d'\''Amour'
</pre></td></tr></table>
</li><li>
Include leading or trailing whitespaces using quoting:
<table><tr><td>&nbsp;</td><td><pre class="example">' this string starts and ends with whitespaces '
</pre></td></tr></table>
</li><li>
Escaping and quoting can be mixed together:
<table><tr><td>&nbsp;</td><td><pre class="example">' The string '\'string\'' is a string '
</pre></td></tr></table>
</li><li>
To include a literal <code>\</code> you can use either escaping or quoting:
<table><tr><td>&nbsp;</td><td><pre class="example">'c:\foo' can be written as c:\\foo
</pre></td></tr></table>
</li></ul>
<p><a name="date-syntax"></a>
</p><a name="Date"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Date">4.2 Date</a></h2>
<p>The accepted syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...]]])|(HHMMSS[.m...]]]))[Z]
now
</pre></td></tr></table>
<p>If the value is &quot;now&quot; it takes the current time.
</p>
<p>Time is local time unless Z is appended, in which case it is
interpreted as UTC.
If the year-month-day part is not specified it takes the current
year-month-day.
</p>
<p><a name="time-duration-syntax"></a>
</p><a name="Time-duration"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Time-duration">4.3 Time duration</a></h2>
<p>There are two accepted syntaxes for expressing time duration.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">[-][<var>HH</var>:]<var>MM</var>:<var>SS</var>[.<var>m</var>...]
</pre></td></tr></table>
<p><var>HH</var> expresses the number of hours, <var>MM</var> the number of minutes
for a maximum of 2 digits, and <var>SS</var> the number of seconds for a
maximum of 2 digits. The <var>m</var> at the end expresses decimal value for
<var>SS</var>.
</p>
<p><em>or</em>
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">[-]<var>S</var>+[.<var>m</var>...]
</pre></td></tr></table>
<p><var>S</var> expresses the number of seconds, with the optional decimal part
<var>m</var>.
</p>
<p>In both expressions, the optional &lsquo;<samp>-</samp>&rsquo; indicates negative duration.
</p>
<a name="Examples-65"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-65">4.3.1 Examples</a></h3>
<p>The following examples are all valid time duration:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>55</samp>&rsquo;</dt>
<dd><p>55 seconds
</p>
</dd>
<dt> &lsquo;<samp>12:03:45</samp>&rsquo;</dt>
<dd><p>12 hours, 03 minutes and 45 seconds
</p>
</dd>
<dt> &lsquo;<samp>23.189</samp>&rsquo;</dt>
<dd><p>23.189 seconds
</p></dd>
</dl>
<p><a name="video-size-syntax"></a>
</p><a name="Video-size"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Video-size">4.4 Video size</a></h2>
<p>Specify the size of the sourced video, it may be a string of the form
<var>width</var>x<var>height</var>, or the name of a size abbreviation.
</p>
<p>The following abbreviations are recognized:
</p><dl compact="compact">
<dt> &lsquo;<samp>ntsc</samp>&rsquo;</dt>
<dd><p>720x480
</p></dd>
<dt> &lsquo;<samp>pal</samp>&rsquo;</dt>
<dd><p>720x576
</p></dd>
<dt> &lsquo;<samp>qntsc</samp>&rsquo;</dt>
<dd><p>352x240
</p></dd>
<dt> &lsquo;<samp>qpal</samp>&rsquo;</dt>
<dd><p>352x288
</p></dd>
<dt> &lsquo;<samp>sntsc</samp>&rsquo;</dt>
<dd><p>640x480
</p></dd>
<dt> &lsquo;<samp>spal</samp>&rsquo;</dt>
<dd><p>768x576
</p></dd>
<dt> &lsquo;<samp>film</samp>&rsquo;</dt>
<dd><p>352x240
</p></dd>
<dt> &lsquo;<samp>ntsc-film</samp>&rsquo;</dt>
<dd><p>352x240
</p></dd>
<dt> &lsquo;<samp>sqcif</samp>&rsquo;</dt>
<dd><p>128x96
</p></dd>
<dt> &lsquo;<samp>qcif</samp>&rsquo;</dt>
<dd><p>176x144
</p></dd>
<dt> &lsquo;<samp>cif</samp>&rsquo;</dt>
<dd><p>352x288
</p></dd>
<dt> &lsquo;<samp>4cif</samp>&rsquo;</dt>
<dd><p>704x576
</p></dd>
<dt> &lsquo;<samp>16cif</samp>&rsquo;</dt>
<dd><p>1408x1152
</p></dd>
<dt> &lsquo;<samp>qqvga</samp>&rsquo;</dt>
<dd><p>160x120
</p></dd>
<dt> &lsquo;<samp>qvga</samp>&rsquo;</dt>
<dd><p>320x240
</p></dd>
<dt> &lsquo;<samp>vga</samp>&rsquo;</dt>
<dd><p>640x480
</p></dd>
<dt> &lsquo;<samp>svga</samp>&rsquo;</dt>
<dd><p>800x600
</p></dd>
<dt> &lsquo;<samp>xga</samp>&rsquo;</dt>
<dd><p>1024x768
</p></dd>
<dt> &lsquo;<samp>uxga</samp>&rsquo;</dt>
<dd><p>1600x1200
</p></dd>
<dt> &lsquo;<samp>qxga</samp>&rsquo;</dt>
<dd><p>2048x1536
</p></dd>
<dt> &lsquo;<samp>sxga</samp>&rsquo;</dt>
<dd><p>1280x1024
</p></dd>
<dt> &lsquo;<samp>qsxga</samp>&rsquo;</dt>
<dd><p>2560x2048
</p></dd>
<dt> &lsquo;<samp>hsxga</samp>&rsquo;</dt>
<dd><p>5120x4096
</p></dd>
<dt> &lsquo;<samp>wvga</samp>&rsquo;</dt>
<dd><p>852x480
</p></dd>
<dt> &lsquo;<samp>wxga</samp>&rsquo;</dt>
<dd><p>1366x768
</p></dd>
<dt> &lsquo;<samp>wsxga</samp>&rsquo;</dt>
<dd><p>1600x1024
</p></dd>
<dt> &lsquo;<samp>wuxga</samp>&rsquo;</dt>
<dd><p>1920x1200
</p></dd>
<dt> &lsquo;<samp>woxga</samp>&rsquo;</dt>
<dd><p>2560x1600
</p></dd>
<dt> &lsquo;<samp>wqsxga</samp>&rsquo;</dt>
<dd><p>3200x2048
</p></dd>
<dt> &lsquo;<samp>wquxga</samp>&rsquo;</dt>
<dd><p>3840x2400
</p></dd>
<dt> &lsquo;<samp>whsxga</samp>&rsquo;</dt>
<dd><p>6400x4096
</p></dd>
<dt> &lsquo;<samp>whuxga</samp>&rsquo;</dt>
<dd><p>7680x4800
</p></dd>
<dt> &lsquo;<samp>cga</samp>&rsquo;</dt>
<dd><p>320x200
</p></dd>
<dt> &lsquo;<samp>ega</samp>&rsquo;</dt>
<dd><p>640x350
</p></dd>
<dt> &lsquo;<samp>hd480</samp>&rsquo;</dt>
<dd><p>852x480
</p></dd>
<dt> &lsquo;<samp>hd720</samp>&rsquo;</dt>
<dd><p>1280x720
</p></dd>
<dt> &lsquo;<samp>hd1080</samp>&rsquo;</dt>
<dd><p>1920x1080
</p></dd>
<dt> &lsquo;<samp>2k</samp>&rsquo;</dt>
<dd><p>2048x1080
</p></dd>
<dt> &lsquo;<samp>2kflat</samp>&rsquo;</dt>
<dd><p>1998x1080
</p></dd>
<dt> &lsquo;<samp>2kscope</samp>&rsquo;</dt>
<dd><p>2048x858
</p></dd>
<dt> &lsquo;<samp>4k</samp>&rsquo;</dt>
<dd><p>4096x2160
</p></dd>
<dt> &lsquo;<samp>4kflat</samp>&rsquo;</dt>
<dd><p>3996x2160
</p></dd>
<dt> &lsquo;<samp>4kscope</samp>&rsquo;</dt>
<dd><p>4096x1716
</p></dd>
<dt> &lsquo;<samp>nhd</samp>&rsquo;</dt>
<dd><p>640x360
</p></dd>
<dt> &lsquo;<samp>hqvga</samp>&rsquo;</dt>
<dd><p>240x160
</p></dd>
<dt> &lsquo;<samp>wqvga</samp>&rsquo;</dt>
<dd><p>400x240
</p></dd>
<dt> &lsquo;<samp>fwqvga</samp>&rsquo;</dt>
<dd><p>432x240
</p></dd>
<dt> &lsquo;<samp>hvga</samp>&rsquo;</dt>
<dd><p>480x320
</p></dd>
<dt> &lsquo;<samp>qhd</samp>&rsquo;</dt>
<dd><p>960x540
</p></dd>
</dl>
<p><a name="video-rate-syntax"></a>
</p><a name="Video-rate"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Video-rate">4.5 Video rate</a></h2>
<p>Specify the frame rate of a video, expressed as the number of frames
generated per second. It has to be a string in the format
<var>frame_rate_num</var>/<var>frame_rate_den</var>, an integer number, a float
number or a valid video frame rate abbreviation.
</p>
<p>The following abbreviations are recognized:
</p><dl compact="compact">
<dt> &lsquo;<samp>ntsc</samp>&rsquo;</dt>
<dd><p>30000/1001
</p></dd>
<dt> &lsquo;<samp>pal</samp>&rsquo;</dt>
<dd><p>25/1
</p></dd>
<dt> &lsquo;<samp>qntsc</samp>&rsquo;</dt>
<dd><p>30000/1001
</p></dd>
<dt> &lsquo;<samp>qpal</samp>&rsquo;</dt>
<dd><p>25/1
</p></dd>
<dt> &lsquo;<samp>sntsc</samp>&rsquo;</dt>
<dd><p>30000/1001
</p></dd>
<dt> &lsquo;<samp>spal</samp>&rsquo;</dt>
<dd><p>25/1
</p></dd>
<dt> &lsquo;<samp>film</samp>&rsquo;</dt>
<dd><p>24/1
</p></dd>
<dt> &lsquo;<samp>ntsc-film</samp>&rsquo;</dt>
<dd><p>24000/1001
</p></dd>
</dl>
<p><a name="ratio-syntax"></a>
</p><a name="Ratio"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Ratio">4.6 Ratio</a></h2>
<p>A ratio can be expressed as an expression, or in the form
<var>numerator</var>:<var>denominator</var>.
</p>
<p>Note that a ratio with infinite (1/0) or negative value is
considered valid, so you should check on the returned value if you
want to exclude those values.
</p>
<p>The undefined value can be expressed using the &quot;0:0&quot; string.
</p>
<p><a name="color-syntax"></a>
</p><a name="Color"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Color">4.7 Color</a></h2>
<p>It can be the name of a color as defined below (case insensitive match) or a
<code>[0x|#]RRGGBB[AA]</code> sequence, possibly followed by @ and a string
representing the alpha component.
</p>
<p>The alpha component may be a string composed by &quot;0x&quot; followed by an
hexadecimal number or a decimal number between 0.0 and 1.0, which
represents the opacity value (&lsquo;<samp>0x00</samp>&rsquo; or &lsquo;<samp>0.0</samp>&rsquo; means completely
transparent, &lsquo;<samp>0xff</samp>&rsquo; or &lsquo;<samp>1.0</samp>&rsquo; completely opaque). If the alpha
component is not specified then &lsquo;<samp>0xff</samp>&rsquo; is assumed.
</p>
<p>The string &lsquo;<samp>random</samp>&rsquo; will result in a random color.
</p>
<p>The following names of colors are recognized:
</p><dl compact="compact">
<dt> &lsquo;<samp>AliceBlue</samp>&rsquo;</dt>
<dd><p>0xF0F8FF
</p></dd>
<dt> &lsquo;<samp>AntiqueWhite</samp>&rsquo;</dt>
<dd><p>0xFAEBD7
</p></dd>
<dt> &lsquo;<samp>Aqua</samp>&rsquo;</dt>
<dd><p>0x00FFFF
</p></dd>
<dt> &lsquo;<samp>Aquamarine</samp>&rsquo;</dt>
<dd><p>0x7FFFD4
</p></dd>
<dt> &lsquo;<samp>Azure</samp>&rsquo;</dt>
<dd><p>0xF0FFFF
</p></dd>
<dt> &lsquo;<samp>Beige</samp>&rsquo;</dt>
<dd><p>0xF5F5DC
</p></dd>
<dt> &lsquo;<samp>Bisque</samp>&rsquo;</dt>
<dd><p>0xFFE4C4
</p></dd>
<dt> &lsquo;<samp>Black</samp>&rsquo;</dt>
<dd><p>0x000000
</p></dd>
<dt> &lsquo;<samp>BlanchedAlmond</samp>&rsquo;</dt>
<dd><p>0xFFEBCD
</p></dd>
<dt> &lsquo;<samp>Blue</samp>&rsquo;</dt>
<dd><p>0x0000FF
</p></dd>
<dt> &lsquo;<samp>BlueViolet</samp>&rsquo;</dt>
<dd><p>0x8A2BE2
</p></dd>
<dt> &lsquo;<samp>Brown</samp>&rsquo;</dt>
<dd><p>0xA52A2A
</p></dd>
<dt> &lsquo;<samp>BurlyWood</samp>&rsquo;</dt>
<dd><p>0xDEB887
</p></dd>
<dt> &lsquo;<samp>CadetBlue</samp>&rsquo;</dt>
<dd><p>0x5F9EA0
</p></dd>
<dt> &lsquo;<samp>Chartreuse</samp>&rsquo;</dt>
<dd><p>0x7FFF00
</p></dd>
<dt> &lsquo;<samp>Chocolate</samp>&rsquo;</dt>
<dd><p>0xD2691E
</p></dd>
<dt> &lsquo;<samp>Coral</samp>&rsquo;</dt>
<dd><p>0xFF7F50
</p></dd>
<dt> &lsquo;<samp>CornflowerBlue</samp>&rsquo;</dt>
<dd><p>0x6495ED
</p></dd>
<dt> &lsquo;<samp>Cornsilk</samp>&rsquo;</dt>
<dd><p>0xFFF8DC
</p></dd>
<dt> &lsquo;<samp>Crimson</samp>&rsquo;</dt>
<dd><p>0xDC143C
</p></dd>
<dt> &lsquo;<samp>Cyan</samp>&rsquo;</dt>
<dd><p>0x00FFFF
</p></dd>
<dt> &lsquo;<samp>DarkBlue</samp>&rsquo;</dt>
<dd><p>0x00008B
</p></dd>
<dt> &lsquo;<samp>DarkCyan</samp>&rsquo;</dt>
<dd><p>0x008B8B
</p></dd>
<dt> &lsquo;<samp>DarkGoldenRod</samp>&rsquo;</dt>
<dd><p>0xB8860B
</p></dd>
<dt> &lsquo;<samp>DarkGray</samp>&rsquo;</dt>
<dd><p>0xA9A9A9
</p></dd>
<dt> &lsquo;<samp>DarkGreen</samp>&rsquo;</dt>
<dd><p>0x006400
</p></dd>
<dt> &lsquo;<samp>DarkKhaki</samp>&rsquo;</dt>
<dd><p>0xBDB76B
</p></dd>
<dt> &lsquo;<samp>DarkMagenta</samp>&rsquo;</dt>
<dd><p>0x8B008B
</p></dd>
<dt> &lsquo;<samp>DarkOliveGreen</samp>&rsquo;</dt>
<dd><p>0x556B2F
</p></dd>
<dt> &lsquo;<samp>Darkorange</samp>&rsquo;</dt>
<dd><p>0xFF8C00
</p></dd>
<dt> &lsquo;<samp>DarkOrchid</samp>&rsquo;</dt>
<dd><p>0x9932CC
</p></dd>
<dt> &lsquo;<samp>DarkRed</samp>&rsquo;</dt>
<dd><p>0x8B0000
</p></dd>
<dt> &lsquo;<samp>DarkSalmon</samp>&rsquo;</dt>
<dd><p>0xE9967A
</p></dd>
<dt> &lsquo;<samp>DarkSeaGreen</samp>&rsquo;</dt>
<dd><p>0x8FBC8F
</p></dd>
<dt> &lsquo;<samp>DarkSlateBlue</samp>&rsquo;</dt>
<dd><p>0x483D8B
</p></dd>
<dt> &lsquo;<samp>DarkSlateGray</samp>&rsquo;</dt>
<dd><p>0x2F4F4F
</p></dd>
<dt> &lsquo;<samp>DarkTurquoise</samp>&rsquo;</dt>
<dd><p>0x00CED1
</p></dd>
<dt> &lsquo;<samp>DarkViolet</samp>&rsquo;</dt>
<dd><p>0x9400D3
</p></dd>
<dt> &lsquo;<samp>DeepPink</samp>&rsquo;</dt>
<dd><p>0xFF1493
</p></dd>
<dt> &lsquo;<samp>DeepSkyBlue</samp>&rsquo;</dt>
<dd><p>0x00BFFF
</p></dd>
<dt> &lsquo;<samp>DimGray</samp>&rsquo;</dt>
<dd><p>0x696969
</p></dd>
<dt> &lsquo;<samp>DodgerBlue</samp>&rsquo;</dt>
<dd><p>0x1E90FF
</p></dd>
<dt> &lsquo;<samp>FireBrick</samp>&rsquo;</dt>
<dd><p>0xB22222
</p></dd>
<dt> &lsquo;<samp>FloralWhite</samp>&rsquo;</dt>
<dd><p>0xFFFAF0
</p></dd>
<dt> &lsquo;<samp>ForestGreen</samp>&rsquo;</dt>
<dd><p>0x228B22
</p></dd>
<dt> &lsquo;<samp>Fuchsia</samp>&rsquo;</dt>
<dd><p>0xFF00FF
</p></dd>
<dt> &lsquo;<samp>Gainsboro</samp>&rsquo;</dt>
<dd><p>0xDCDCDC
</p></dd>
<dt> &lsquo;<samp>GhostWhite</samp>&rsquo;</dt>
<dd><p>0xF8F8FF
</p></dd>
<dt> &lsquo;<samp>Gold</samp>&rsquo;</dt>
<dd><p>0xFFD700
</p></dd>
<dt> &lsquo;<samp>GoldenRod</samp>&rsquo;</dt>
<dd><p>0xDAA520
</p></dd>
<dt> &lsquo;<samp>Gray</samp>&rsquo;</dt>
<dd><p>0x808080
</p></dd>
<dt> &lsquo;<samp>Green</samp>&rsquo;</dt>
<dd><p>0x008000
</p></dd>
<dt> &lsquo;<samp>GreenYellow</samp>&rsquo;</dt>
<dd><p>0xADFF2F
</p></dd>
<dt> &lsquo;<samp>HoneyDew</samp>&rsquo;</dt>
<dd><p>0xF0FFF0
</p></dd>
<dt> &lsquo;<samp>HotPink</samp>&rsquo;</dt>
<dd><p>0xFF69B4
</p></dd>
<dt> &lsquo;<samp>IndianRed</samp>&rsquo;</dt>
<dd><p>0xCD5C5C
</p></dd>
<dt> &lsquo;<samp>Indigo</samp>&rsquo;</dt>
<dd><p>0x4B0082
</p></dd>
<dt> &lsquo;<samp>Ivory</samp>&rsquo;</dt>
<dd><p>0xFFFFF0
</p></dd>
<dt> &lsquo;<samp>Khaki</samp>&rsquo;</dt>
<dd><p>0xF0E68C
</p></dd>
<dt> &lsquo;<samp>Lavender</samp>&rsquo;</dt>
<dd><p>0xE6E6FA
</p></dd>
<dt> &lsquo;<samp>LavenderBlush</samp>&rsquo;</dt>
<dd><p>0xFFF0F5
</p></dd>
<dt> &lsquo;<samp>LawnGreen</samp>&rsquo;</dt>
<dd><p>0x7CFC00
</p></dd>
<dt> &lsquo;<samp>LemonChiffon</samp>&rsquo;</dt>
<dd><p>0xFFFACD
</p></dd>
<dt> &lsquo;<samp>LightBlue</samp>&rsquo;</dt>
<dd><p>0xADD8E6
</p></dd>
<dt> &lsquo;<samp>LightCoral</samp>&rsquo;</dt>
<dd><p>0xF08080
</p></dd>
<dt> &lsquo;<samp>LightCyan</samp>&rsquo;</dt>
<dd><p>0xE0FFFF
</p></dd>
<dt> &lsquo;<samp>LightGoldenRodYellow</samp>&rsquo;</dt>
<dd><p>0xFAFAD2
</p></dd>
<dt> &lsquo;<samp>LightGreen</samp>&rsquo;</dt>
<dd><p>0x90EE90
</p></dd>
<dt> &lsquo;<samp>LightGrey</samp>&rsquo;</dt>
<dd><p>0xD3D3D3
</p></dd>
<dt> &lsquo;<samp>LightPink</samp>&rsquo;</dt>
<dd><p>0xFFB6C1
</p></dd>
<dt> &lsquo;<samp>LightSalmon</samp>&rsquo;</dt>
<dd><p>0xFFA07A
</p></dd>
<dt> &lsquo;<samp>LightSeaGreen</samp>&rsquo;</dt>
<dd><p>0x20B2AA
</p></dd>
<dt> &lsquo;<samp>LightSkyBlue</samp>&rsquo;</dt>
<dd><p>0x87CEFA
</p></dd>
<dt> &lsquo;<samp>LightSlateGray</samp>&rsquo;</dt>
<dd><p>0x778899
</p></dd>
<dt> &lsquo;<samp>LightSteelBlue</samp>&rsquo;</dt>
<dd><p>0xB0C4DE
</p></dd>
<dt> &lsquo;<samp>LightYellow</samp>&rsquo;</dt>
<dd><p>0xFFFFE0
</p></dd>
<dt> &lsquo;<samp>Lime</samp>&rsquo;</dt>
<dd><p>0x00FF00
</p></dd>
<dt> &lsquo;<samp>LimeGreen</samp>&rsquo;</dt>
<dd><p>0x32CD32
</p></dd>
<dt> &lsquo;<samp>Linen</samp>&rsquo;</dt>
<dd><p>0xFAF0E6
</p></dd>
<dt> &lsquo;<samp>Magenta</samp>&rsquo;</dt>
<dd><p>0xFF00FF
</p></dd>
<dt> &lsquo;<samp>Maroon</samp>&rsquo;</dt>
<dd><p>0x800000
</p></dd>
<dt> &lsquo;<samp>MediumAquaMarine</samp>&rsquo;</dt>
<dd><p>0x66CDAA
</p></dd>
<dt> &lsquo;<samp>MediumBlue</samp>&rsquo;</dt>
<dd><p>0x0000CD
</p></dd>
<dt> &lsquo;<samp>MediumOrchid</samp>&rsquo;</dt>
<dd><p>0xBA55D3
</p></dd>
<dt> &lsquo;<samp>MediumPurple</samp>&rsquo;</dt>
<dd><p>0x9370D8
</p></dd>
<dt> &lsquo;<samp>MediumSeaGreen</samp>&rsquo;</dt>
<dd><p>0x3CB371
</p></dd>
<dt> &lsquo;<samp>MediumSlateBlue</samp>&rsquo;</dt>
<dd><p>0x7B68EE
</p></dd>
<dt> &lsquo;<samp>MediumSpringGreen</samp>&rsquo;</dt>
<dd><p>0x00FA9A
</p></dd>
<dt> &lsquo;<samp>MediumTurquoise</samp>&rsquo;</dt>
<dd><p>0x48D1CC
</p></dd>
<dt> &lsquo;<samp>MediumVioletRed</samp>&rsquo;</dt>
<dd><p>0xC71585
</p></dd>
<dt> &lsquo;<samp>MidnightBlue</samp>&rsquo;</dt>
<dd><p>0x191970
</p></dd>
<dt> &lsquo;<samp>MintCream</samp>&rsquo;</dt>
<dd><p>0xF5FFFA
</p></dd>
<dt> &lsquo;<samp>MistyRose</samp>&rsquo;</dt>
<dd><p>0xFFE4E1
</p></dd>
<dt> &lsquo;<samp>Moccasin</samp>&rsquo;</dt>
<dd><p>0xFFE4B5
</p></dd>
<dt> &lsquo;<samp>NavajoWhite</samp>&rsquo;</dt>
<dd><p>0xFFDEAD
</p></dd>
<dt> &lsquo;<samp>Navy</samp>&rsquo;</dt>
<dd><p>0x000080
</p></dd>
<dt> &lsquo;<samp>OldLace</samp>&rsquo;</dt>
<dd><p>0xFDF5E6
</p></dd>
<dt> &lsquo;<samp>Olive</samp>&rsquo;</dt>
<dd><p>0x808000
</p></dd>
<dt> &lsquo;<samp>OliveDrab</samp>&rsquo;</dt>
<dd><p>0x6B8E23
</p></dd>
<dt> &lsquo;<samp>Orange</samp>&rsquo;</dt>
<dd><p>0xFFA500
</p></dd>
<dt> &lsquo;<samp>OrangeRed</samp>&rsquo;</dt>
<dd><p>0xFF4500
</p></dd>
<dt> &lsquo;<samp>Orchid</samp>&rsquo;</dt>
<dd><p>0xDA70D6
</p></dd>
<dt> &lsquo;<samp>PaleGoldenRod</samp>&rsquo;</dt>
<dd><p>0xEEE8AA
</p></dd>
<dt> &lsquo;<samp>PaleGreen</samp>&rsquo;</dt>
<dd><p>0x98FB98
</p></dd>
<dt> &lsquo;<samp>PaleTurquoise</samp>&rsquo;</dt>
<dd><p>0xAFEEEE
</p></dd>
<dt> &lsquo;<samp>PaleVioletRed</samp>&rsquo;</dt>
<dd><p>0xD87093
</p></dd>
<dt> &lsquo;<samp>PapayaWhip</samp>&rsquo;</dt>
<dd><p>0xFFEFD5
</p></dd>
<dt> &lsquo;<samp>PeachPuff</samp>&rsquo;</dt>
<dd><p>0xFFDAB9
</p></dd>
<dt> &lsquo;<samp>Peru</samp>&rsquo;</dt>
<dd><p>0xCD853F
</p></dd>
<dt> &lsquo;<samp>Pink</samp>&rsquo;</dt>
<dd><p>0xFFC0CB
</p></dd>
<dt> &lsquo;<samp>Plum</samp>&rsquo;</dt>
<dd><p>0xDDA0DD
</p></dd>
<dt> &lsquo;<samp>PowderBlue</samp>&rsquo;</dt>
<dd><p>0xB0E0E6
</p></dd>
<dt> &lsquo;<samp>Purple</samp>&rsquo;</dt>
<dd><p>0x800080
</p></dd>
<dt> &lsquo;<samp>Red</samp>&rsquo;</dt>
<dd><p>0xFF0000
</p></dd>
<dt> &lsquo;<samp>RosyBrown</samp>&rsquo;</dt>
<dd><p>0xBC8F8F
</p></dd>
<dt> &lsquo;<samp>RoyalBlue</samp>&rsquo;</dt>
<dd><p>0x4169E1
</p></dd>
<dt> &lsquo;<samp>SaddleBrown</samp>&rsquo;</dt>
<dd><p>0x8B4513
</p></dd>
<dt> &lsquo;<samp>Salmon</samp>&rsquo;</dt>
<dd><p>0xFA8072
</p></dd>
<dt> &lsquo;<samp>SandyBrown</samp>&rsquo;</dt>
<dd><p>0xF4A460
</p></dd>
<dt> &lsquo;<samp>SeaGreen</samp>&rsquo;</dt>
<dd><p>0x2E8B57
</p></dd>
<dt> &lsquo;<samp>SeaShell</samp>&rsquo;</dt>
<dd><p>0xFFF5EE
</p></dd>
<dt> &lsquo;<samp>Sienna</samp>&rsquo;</dt>
<dd><p>0xA0522D
</p></dd>
<dt> &lsquo;<samp>Silver</samp>&rsquo;</dt>
<dd><p>0xC0C0C0
</p></dd>
<dt> &lsquo;<samp>SkyBlue</samp>&rsquo;</dt>
<dd><p>0x87CEEB
</p></dd>
<dt> &lsquo;<samp>SlateBlue</samp>&rsquo;</dt>
<dd><p>0x6A5ACD
</p></dd>
<dt> &lsquo;<samp>SlateGray</samp>&rsquo;</dt>
<dd><p>0x708090
</p></dd>
<dt> &lsquo;<samp>Snow</samp>&rsquo;</dt>
<dd><p>0xFFFAFA
</p></dd>
<dt> &lsquo;<samp>SpringGreen</samp>&rsquo;</dt>
<dd><p>0x00FF7F
</p></dd>
<dt> &lsquo;<samp>SteelBlue</samp>&rsquo;</dt>
<dd><p>0x4682B4
</p></dd>
<dt> &lsquo;<samp>Tan</samp>&rsquo;</dt>
<dd><p>0xD2B48C
</p></dd>
<dt> &lsquo;<samp>Teal</samp>&rsquo;</dt>
<dd><p>0x008080
</p></dd>
<dt> &lsquo;<samp>Thistle</samp>&rsquo;</dt>
<dd><p>0xD8BFD8
</p></dd>
<dt> &lsquo;<samp>Tomato</samp>&rsquo;</dt>
<dd><p>0xFF6347
</p></dd>
<dt> &lsquo;<samp>Turquoise</samp>&rsquo;</dt>
<dd><p>0x40E0D0
</p></dd>
<dt> &lsquo;<samp>Violet</samp>&rsquo;</dt>
<dd><p>0xEE82EE
</p></dd>
<dt> &lsquo;<samp>Wheat</samp>&rsquo;</dt>
<dd><p>0xF5DEB3
</p></dd>
<dt> &lsquo;<samp>White</samp>&rsquo;</dt>
<dd><p>0xFFFFFF
</p></dd>
<dt> &lsquo;<samp>WhiteSmoke</samp>&rsquo;</dt>
<dd><p>0xF5F5F5
</p></dd>
<dt> &lsquo;<samp>Yellow</samp>&rsquo;</dt>
<dd><p>0xFFFF00
</p></dd>
<dt> &lsquo;<samp>YellowGreen</samp>&rsquo;</dt>
<dd><p>0x9ACD32
</p></dd>
</dl>
<p><a name="channel-layout-syntax"></a>
</p><a name="Channel-Layout"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Channel-Layout">4.8 Channel Layout</a></h2>
<p>A channel layout specifies the spatial disposition of the channels in
a multi-channel audio stream. To specify a channel layout, FFmpeg
makes use of a special syntax.
</p>
<p>Individual channels are identified by an id, as given by the table
below:
</p><dl compact="compact">
<dt> &lsquo;<samp>FL</samp>&rsquo;</dt>
<dd><p>front left
</p></dd>
<dt> &lsquo;<samp>FR</samp>&rsquo;</dt>
<dd><p>front right
</p></dd>
<dt> &lsquo;<samp>FC</samp>&rsquo;</dt>
<dd><p>front center
</p></dd>
<dt> &lsquo;<samp>LFE</samp>&rsquo;</dt>
<dd><p>low frequency
</p></dd>
<dt> &lsquo;<samp>BL</samp>&rsquo;</dt>
<dd><p>back left
</p></dd>
<dt> &lsquo;<samp>BR</samp>&rsquo;</dt>
<dd><p>back right
</p></dd>
<dt> &lsquo;<samp>FLC</samp>&rsquo;</dt>
<dd><p>front left-of-center
</p></dd>
<dt> &lsquo;<samp>FRC</samp>&rsquo;</dt>
<dd><p>front right-of-center
</p></dd>
<dt> &lsquo;<samp>BC</samp>&rsquo;</dt>
<dd><p>back center
</p></dd>
<dt> &lsquo;<samp>SL</samp>&rsquo;</dt>
<dd><p>side left
</p></dd>
<dt> &lsquo;<samp>SR</samp>&rsquo;</dt>
<dd><p>side right
</p></dd>
<dt> &lsquo;<samp>TC</samp>&rsquo;</dt>
<dd><p>top center
</p></dd>
<dt> &lsquo;<samp>TFL</samp>&rsquo;</dt>
<dd><p>top front left
</p></dd>
<dt> &lsquo;<samp>TFC</samp>&rsquo;</dt>
<dd><p>top front center
</p></dd>
<dt> &lsquo;<samp>TFR</samp>&rsquo;</dt>
<dd><p>top front right
</p></dd>
<dt> &lsquo;<samp>TBL</samp>&rsquo;</dt>
<dd><p>top back left
</p></dd>
<dt> &lsquo;<samp>TBC</samp>&rsquo;</dt>
<dd><p>top back center
</p></dd>
<dt> &lsquo;<samp>TBR</samp>&rsquo;</dt>
<dd><p>top back right
</p></dd>
<dt> &lsquo;<samp>DL</samp>&rsquo;</dt>
<dd><p>downmix left
</p></dd>
<dt> &lsquo;<samp>DR</samp>&rsquo;</dt>
<dd><p>downmix right
</p></dd>
<dt> &lsquo;<samp>WL</samp>&rsquo;</dt>
<dd><p>wide left
</p></dd>
<dt> &lsquo;<samp>WR</samp>&rsquo;</dt>
<dd><p>wide right
</p></dd>
<dt> &lsquo;<samp>SDL</samp>&rsquo;</dt>
<dd><p>surround direct left
</p></dd>
<dt> &lsquo;<samp>SDR</samp>&rsquo;</dt>
<dd><p>surround direct right
</p></dd>
<dt> &lsquo;<samp>LFE2</samp>&rsquo;</dt>
<dd><p>low frequency 2
</p></dd>
</dl>
<p>Standard channel layout compositions can be specified by using the
following identifiers:
</p><dl compact="compact">
<dt> &lsquo;<samp>mono</samp>&rsquo;</dt>
<dd><p>FC
</p></dd>
<dt> &lsquo;<samp>stereo</samp>&rsquo;</dt>
<dd><p>FL+FR
</p></dd>
<dt> &lsquo;<samp>2.1</samp>&rsquo;</dt>
<dd><p>FL+FR+LFE
</p></dd>
<dt> &lsquo;<samp>3.0</samp>&rsquo;</dt>
<dd><p>FL+FR+FC
</p></dd>
<dt> &lsquo;<samp>3.0(back)</samp>&rsquo;</dt>
<dd><p>FL+FR+BC
</p></dd>
<dt> &lsquo;<samp>4.0</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+BC
</p></dd>
<dt> &lsquo;<samp>quad</samp>&rsquo;</dt>
<dd><p>FL+FR+BL+BR
</p></dd>
<dt> &lsquo;<samp>quad(side)</samp>&rsquo;</dt>
<dd><p>FL+FR+SL+SR
</p></dd>
<dt> &lsquo;<samp>3.1</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE
</p></dd>
<dt> &lsquo;<samp>5.0</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+BL+BR
</p></dd>
<dt> &lsquo;<samp>5.0(side)</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+SL+SR
</p></dd>
<dt> &lsquo;<samp>4.1</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+BC
</p></dd>
<dt> &lsquo;<samp>5.1</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+BL+BR
</p></dd>
<dt> &lsquo;<samp>5.1(side)</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+SL+SR
</p></dd>
<dt> &lsquo;<samp>6.0</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+BC+SL+SR
</p></dd>
<dt> &lsquo;<samp>6.0(front)</samp>&rsquo;</dt>
<dd><p>FL+FR+FLC+FRC+SL+SR
</p></dd>
<dt> &lsquo;<samp>hexagonal</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+BL+BR+BC
</p></dd>
<dt> &lsquo;<samp>6.1</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+BC+SL+SR
</p></dd>
<dt> &lsquo;<samp>6.1</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+BL+BR+BC
</p></dd>
<dt> &lsquo;<samp>6.1(front)</samp>&rsquo;</dt>
<dd><p>FL+FR+LFE+FLC+FRC+SL+SR
</p></dd>
<dt> &lsquo;<samp>7.0</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+BL+BR+SL+SR
</p></dd>
<dt> &lsquo;<samp>7.0(front)</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+FLC+FRC+SL+SR
</p></dd>
<dt> &lsquo;<samp>7.1</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+BL+BR+SL+SR
</p></dd>
<dt> &lsquo;<samp>7.1(wide)</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+BL+BR+FLC+FRC
</p></dd>
<dt> &lsquo;<samp>7.1(wide-side)</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+LFE+FLC+FRC+SL+SR
</p></dd>
<dt> &lsquo;<samp>octagonal</samp>&rsquo;</dt>
<dd><p>FL+FR+FC+BL+BR+BC+SL+SR
</p></dd>
<dt> &lsquo;<samp>downmix</samp>&rsquo;</dt>
<dd><p>DL+DR
</p></dd>
</dl>
<p>A custom channel layout can be specified as a sequence of terms, separated by
&rsquo;+&rsquo; or &rsquo;|&rsquo;. Each term can be:
</p><ul>
<li>
the name of a standard channel layout (e.g. &lsquo;<samp>mono</samp>&rsquo;,
&lsquo;<samp>stereo</samp>&rsquo;, &lsquo;<samp>4.0</samp>&rsquo;, &lsquo;<samp>quad</samp>&rsquo;, &lsquo;<samp>5.0</samp>&rsquo;, etc.)
</li><li>
the name of a single channel (e.g. &lsquo;<samp>FL</samp>&rsquo;, &lsquo;<samp>FR</samp>&rsquo;, &lsquo;<samp>FC</samp>&rsquo;, &lsquo;<samp>LFE</samp>&rsquo;, etc.)
</li><li>
a number of channels, in decimal, optionally followed by &rsquo;c&rsquo;, yielding
the default channel layout for that number of channels (see the
function <code>av_get_default_channel_layout</code>)
</li><li>
a channel layout mask, in hexadecimal starting with &quot;0x&quot; (see the
<code>AV_CH_*</code> macros in &lsquo;<tt>libavutil/channel_layout.h</tt>&rsquo;.
</li></ul>
<p>Starting from libavutil version 53 the trailing character &quot;c&quot; to
specify a number of channels will be required, while a channel layout
mask could also be specified as a decimal number (if and only if not
followed by &quot;c&quot;).
</p>
<p>See also the function <code>av_get_channel_layout</code> defined in
&lsquo;<tt>libavutil/channel_layout.h</tt>&rsquo;.
</p>
<a name="Expression-Evaluation"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Expression-Evaluation">5. Expression Evaluation</a></h1>
<p>When evaluating an arithmetic expression, FFmpeg uses an internal
formula evaluator, implemented through the &lsquo;<tt>libavutil/eval.h</tt>&rsquo;
interface.
</p>
<p>An expression may contain unary, binary operators, constants, and
functions.
</p>
<p>Two expressions <var>expr1</var> and <var>expr2</var> can be combined to form
another expression &quot;<var>expr1</var>;<var>expr2</var>&quot;.
<var>expr1</var> and <var>expr2</var> are evaluated in turn, and the new
expression evaluates to the value of <var>expr2</var>.
</p>
<p>The following binary operators are available: <code>+</code>, <code>-</code>,
<code>*</code>, <code>/</code>, <code>^</code>.
</p>
<p>The following unary operators are available: <code>+</code>, <code>-</code>.
</p>
<p>The following functions are available:
</p><dl compact="compact">
<dt> &lsquo;<samp>abs(x)</samp>&rsquo;</dt>
<dd><p>Compute absolute value of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>acos(x)</samp>&rsquo;</dt>
<dd><p>Compute arccosine of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>asin(x)</samp>&rsquo;</dt>
<dd><p>Compute arcsine of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>atan(x)</samp>&rsquo;</dt>
<dd><p>Compute arctangent of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>between(x, min, max)</samp>&rsquo;</dt>
<dd><p>Return 1 if <var>x</var> is greater than or equal to <var>min</var> and lesser than or
equal to <var>max</var>, 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>bitand(x, y)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bitor(x, y)</samp>&rsquo;</dt>
<dd><p>Compute bitwise and/or operation on <var>x</var> and <var>y</var>.
</p>
<p>The results of the evaluation of <var>x</var> and <var>y</var> are converted to
integers before executing the bitwise operation.
</p>
<p>Note that both the conversion to integer and the conversion back to
floating point can lose precision. Beware of unexpected results for
large numbers (usually 2^53 and larger).
</p>
</dd>
<dt> &lsquo;<samp>ceil(expr)</samp>&rsquo;</dt>
<dd><p>Round the value of expression <var>expr</var> upwards to the nearest
integer. For example, &quot;ceil(1.5)&quot; is &quot;2.0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>cos(x)</samp>&rsquo;</dt>
<dd><p>Compute cosine of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>cosh(x)</samp>&rsquo;</dt>
<dd><p>Compute hyperbolic cosine of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>eq(x, y)</samp>&rsquo;</dt>
<dd><p>Return 1 if <var>x</var> and <var>y</var> are equivalent, 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>exp(x)</samp>&rsquo;</dt>
<dd><p>Compute exponential of <var>x</var> (with base <code>e</code>, the Euler&rsquo;s number).
</p>
</dd>
<dt> &lsquo;<samp>floor(expr)</samp>&rsquo;</dt>
<dd><p>Round the value of expression <var>expr</var> downwards to the nearest
integer. For example, &quot;floor(-1.5)&quot; is &quot;-2.0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>gauss(x)</samp>&rsquo;</dt>
<dd><p>Compute Gauss function of <var>x</var>, corresponding to
<code>exp(-x*x/2) / sqrt(2*PI)</code>.
</p>
</dd>
<dt> &lsquo;<samp>gcd(x, y)</samp>&rsquo;</dt>
<dd><p>Return the greatest common divisor of <var>x</var> and <var>y</var>. If both <var>x</var> and
<var>y</var> are 0 or either or both are less than zero then behavior is undefined.
</p>
</dd>
<dt> &lsquo;<samp>gt(x, y)</samp>&rsquo;</dt>
<dd><p>Return 1 if <var>x</var> is greater than <var>y</var>, 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>gte(x, y)</samp>&rsquo;</dt>
<dd><p>Return 1 if <var>x</var> is greater than or equal to <var>y</var>, 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>hypot(x, y)</samp>&rsquo;</dt>
<dd><p>This function is similar to the C function with the same name; it returns
&quot;sqrt(<var>x</var>*<var>x</var> + <var>y</var>*<var>y</var>)&quot;, the length of the hypotenuse of a
right triangle with sides of length <var>x</var> and <var>y</var>, or the distance of the
point (<var>x</var>, <var>y</var>) from the origin.
</p>
</dd>
<dt> &lsquo;<samp>if(x, y)</samp>&rsquo;</dt>
<dd><p>Evaluate <var>x</var>, and if the result is non-zero return the result of
the evaluation of <var>y</var>, return 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>if(x, y, z)</samp>&rsquo;</dt>
<dd><p>Evaluate <var>x</var>, and if the result is non-zero return the evaluation
result of <var>y</var>, otherwise the evaluation result of <var>z</var>.
</p>
</dd>
<dt> &lsquo;<samp>ifnot(x, y)</samp>&rsquo;</dt>
<dd><p>Evaluate <var>x</var>, and if the result is zero return the result of the
evaluation of <var>y</var>, return 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>ifnot(x, y, z)</samp>&rsquo;</dt>
<dd><p>Evaluate <var>x</var>, and if the result is zero return the evaluation
result of <var>y</var>, otherwise the evaluation result of <var>z</var>.
</p>
</dd>
<dt> &lsquo;<samp>isinf(x)</samp>&rsquo;</dt>
<dd><p>Return 1.0 if <var>x</var> is +/-INFINITY, 0.0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>isnan(x)</samp>&rsquo;</dt>
<dd><p>Return 1.0 if <var>x</var> is NAN, 0.0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>ld(var)</samp>&rsquo;</dt>
<dd><p>Allow to load the value of the internal variable with number
<var>var</var>, which was previously stored with st(<var>var</var>, <var>expr</var>).
The function returns the loaded value.
</p>
</dd>
<dt> &lsquo;<samp>log(x)</samp>&rsquo;</dt>
<dd><p>Compute natural logarithm of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>lt(x, y)</samp>&rsquo;</dt>
<dd><p>Return 1 if <var>x</var> is lesser than <var>y</var>, 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>lte(x, y)</samp>&rsquo;</dt>
<dd><p>Return 1 if <var>x</var> is lesser than or equal to <var>y</var>, 0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>max(x, y)</samp>&rsquo;</dt>
<dd><p>Return the maximum between <var>x</var> and <var>y</var>.
</p>
</dd>
<dt> &lsquo;<samp>min(x, y)</samp>&rsquo;</dt>
<dd><p>Return the maximum between <var>x</var> and <var>y</var>.
</p>
</dd>
<dt> &lsquo;<samp>mod(x, y)</samp>&rsquo;</dt>
<dd><p>Compute the remainder of division of <var>x</var> by <var>y</var>.
</p>
</dd>
<dt> &lsquo;<samp>not(expr)</samp>&rsquo;</dt>
<dd><p>Return 1.0 if <var>expr</var> is zero, 0.0 otherwise.
</p>
</dd>
<dt> &lsquo;<samp>pow(x, y)</samp>&rsquo;</dt>
<dd><p>Compute the power of <var>x</var> elevated <var>y</var>, it is equivalent to
&quot;(<var>x</var>)^(<var>y</var>)&quot;.
</p>
</dd>
<dt> &lsquo;<samp>print(t)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>print(t, l)</samp>&rsquo;</dt>
<dd><p>Print the value of expression <var>t</var> with loglevel <var>l</var>. If
<var>l</var> is not specified then a default log level is used.
Returns the value of the expression printed.
</p>
<p>Prints t with loglevel l
</p>
</dd>
<dt> &lsquo;<samp>random(x)</samp>&rsquo;</dt>
<dd><p>Return a pseudo random value between 0.0 and 1.0. <var>x</var> is the index of the
internal variable which will be used to save the seed/state.
</p>
</dd>
<dt> &lsquo;<samp>root(expr, max)</samp>&rsquo;</dt>
<dd><p>Find an input value for which the function represented by <var>expr</var>
with argument <var>ld(0)</var> is 0 in the interval 0..<var>max</var>.
</p>
<p>The expression in <var>expr</var> must denote a continuous function or the
result is undefined.
</p>
<p><var>ld(0)</var> is used to represent the function input value, which means
that the given expression will be evaluated multiple times with
various input values that the expression can access through
<code>ld(0)</code>. When the expression evaluates to 0 then the
corresponding input value will be returned.
</p>
</dd>
<dt> &lsquo;<samp>sin(x)</samp>&rsquo;</dt>
<dd><p>Compute sine of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>sinh(x)</samp>&rsquo;</dt>
<dd><p>Compute hyperbolic sine of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>sqrt(expr)</samp>&rsquo;</dt>
<dd><p>Compute the square root of <var>expr</var>. This is equivalent to
&quot;(<var>expr</var>)^.5&quot;.
</p>
</dd>
<dt> &lsquo;<samp>squish(x)</samp>&rsquo;</dt>
<dd><p>Compute expression <code>1/(1 + exp(4*x))</code>.
</p>
</dd>
<dt> &lsquo;<samp>st(var, expr)</samp>&rsquo;</dt>
<dd><p>Allow to store the value of the expression <var>expr</var> in an internal
variable. <var>var</var> specifies the number of the variable where to
store the value, and it is a value ranging from 0 to 9. The function
returns the value stored in the internal variable.
Note, Variables are currently not shared between expressions.
</p>
</dd>
<dt> &lsquo;<samp>tan(x)</samp>&rsquo;</dt>
<dd><p>Compute tangent of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>tanh(x)</samp>&rsquo;</dt>
<dd><p>Compute hyperbolic tangent of <var>x</var>.
</p>
</dd>
<dt> &lsquo;<samp>taylor(expr, x)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>taylor(expr, x, id)</samp>&rsquo;</dt>
<dd><p>Evaluate a Taylor series at <var>x</var>, given an expression representing
the <code>ld(id)</code>-th derivative of a function at 0.
</p>
<p>When the series does not converge the result is undefined.
</p>
<p><var>ld(id)</var> is used to represent the derivative order in <var>expr</var>,
which means that the given expression will be evaluated multiple times
with various input values that the expression can access through
<code>ld(id)</code>. If <var>id</var> is not specified then 0 is assumed.
</p>
<p>Note, when you have the derivatives at y instead of 0,
<code>taylor(expr, x-y)</code> can be used.
</p>
</dd>
<dt> &lsquo;<samp>time(0)</samp>&rsquo;</dt>
<dd><p>Return the current (wallclock) time in seconds.
</p>
</dd>
<dt> &lsquo;<samp>trunc(expr)</samp>&rsquo;</dt>
<dd><p>Round the value of expression <var>expr</var> towards zero to the nearest
integer. For example, &quot;trunc(-1.5)&quot; is &quot;-1.0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>while(cond, expr)</samp>&rsquo;</dt>
<dd><p>Evaluate expression <var>expr</var> while the expression <var>cond</var> is
non-zero, and returns the value of the last <var>expr</var> evaluation, or
NAN if <var>cond</var> was always false.
</p></dd>
</dl>
<p>The following constants are available:
</p><dl compact="compact">
<dt> &lsquo;<samp>PI</samp>&rsquo;</dt>
<dd><p>area of the unit disc, approximately 3.14
</p></dd>
<dt> &lsquo;<samp>E</samp>&rsquo;</dt>
<dd><p>exp(1) (Euler&rsquo;s number), approximately 2.718
</p></dd>
<dt> &lsquo;<samp>PHI</samp>&rsquo;</dt>
<dd><p>golden ratio (1+sqrt(5))/2, approximately 1.618
</p></dd>
</dl>
<p>Assuming that an expression is considered &quot;true&quot; if it has a non-zero
value, note that:
</p>
<p><code>*</code> works like AND
</p>
<p><code>+</code> works like OR
</p>
<p>For example the construct:
</p><table><tr><td>&nbsp;</td><td><pre class="example">if (A AND B) then C
</pre></td></tr></table>
<p>is equivalent to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">if(A*B, C)
</pre></td></tr></table>
<p>In your C code, you can extend the list of unary and binary functions,
and define recognized constants, so that they are available for your
expressions.
</p>
<p>The evaluator also recognizes the International System unit prefixes.
If &rsquo;i&rsquo; is appended after the prefix, binary prefixes are used, which
are based on powers of 1024 instead of powers of 1000.
The &rsquo;B&rsquo; postfix multiplies the value by 8, and can be appended after a
unit prefix or used alone. This allows using for example &rsquo;KB&rsquo;, &rsquo;MiB&rsquo;,
&rsquo;G&rsquo; and &rsquo;B&rsquo; as number postfix.
</p>
<p>The list of available International System prefixes follows, with
indication of the corresponding powers of 10 and of 2.
</p><dl compact="compact">
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>10^-24 / 2^-80
</p></dd>
<dt> &lsquo;<samp>z</samp>&rsquo;</dt>
<dd><p>10^-21 / 2^-70
</p></dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>10^-18 / 2^-60
</p></dd>
<dt> &lsquo;<samp>f</samp>&rsquo;</dt>
<dd><p>10^-15 / 2^-50
</p></dd>
<dt> &lsquo;<samp>p</samp>&rsquo;</dt>
<dd><p>10^-12 / 2^-40
</p></dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>10^-9 / 2^-30
</p></dd>
<dt> &lsquo;<samp>u</samp>&rsquo;</dt>
<dd><p>10^-6 / 2^-20
</p></dd>
<dt> &lsquo;<samp>m</samp>&rsquo;</dt>
<dd><p>10^-3 / 2^-10
</p></dd>
<dt> &lsquo;<samp>c</samp>&rsquo;</dt>
<dd><p>10^-2
</p></dd>
<dt> &lsquo;<samp>d</samp>&rsquo;</dt>
<dd><p>10^-1
</p></dd>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>10^2
</p></dd>
<dt> &lsquo;<samp>k</samp>&rsquo;</dt>
<dd><p>10^3 / 2^10
</p></dd>
<dt> &lsquo;<samp>K</samp>&rsquo;</dt>
<dd><p>10^3 / 2^10
</p></dd>
<dt> &lsquo;<samp>M</samp>&rsquo;</dt>
<dd><p>10^6 / 2^20
</p></dd>
<dt> &lsquo;<samp>G</samp>&rsquo;</dt>
<dd><p>10^9 / 2^30
</p></dd>
<dt> &lsquo;<samp>T</samp>&rsquo;</dt>
<dd><p>10^12 / 2^40
</p></dd>
<dt> &lsquo;<samp>P</samp>&rsquo;</dt>
<dd><p>10^15 / 2^40
</p></dd>
<dt> &lsquo;<samp>E</samp>&rsquo;</dt>
<dd><p>10^18 / 2^50
</p></dd>
<dt> &lsquo;<samp>Z</samp>&rsquo;</dt>
<dd><p>10^21 / 2^60
</p></dd>
<dt> &lsquo;<samp>Y</samp>&rsquo;</dt>
<dd><p>10^24 / 2^70
</p></dd>
</dl>
<a name="OpenCL-Options"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-OpenCL-Options">6. OpenCL Options</a></h1>
<p>When FFmpeg is configured with <code>--enable-opencl</code>, it is possible
to set the options for the global OpenCL context.
</p>
<p>The list of supported options follows:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>build_options</samp>&rsquo;</dt>
<dd><p>Set build options used to compile the registered kernels.
</p>
<p>See reference &quot;OpenCL Specification Version: 1.2 chapter 5.6.4&quot;.
</p>
</dd>
<dt> &lsquo;<samp>platform_idx</samp>&rsquo;</dt>
<dd><p>Select the index of the platform to run OpenCL code.
</p>
<p>The specified index must be one of the indexes in the device list
which can be obtained with <code>ffmpeg -opencl_bench</code> or <code>av_opencl_get_device_list()</code>.
</p>
</dd>
<dt> &lsquo;<samp>device_idx</samp>&rsquo;</dt>
<dd><p>Select the index of the device used to run OpenCL code.
</p>
<p>The specified index must be one of the indexes in the device list which
can be obtained with <code>ffmpeg -opencl_bench</code> or <code>av_opencl_get_device_list()</code>.
</p>
</dd>
</dl>
<p><a name="codec_002doptions"></a>
</p><a name="Codec-Options"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Codec-Options">7. Codec Options</a></h1>
<p>libavcodec provides some generic global options, which can be set on
all the encoders and decoders. In addition each codec may support
so-called private options, which are specific for a given codec.
</p>
<p>Sometimes, a global option may only affect a specific kind of codec,
and may be unsensical or ignored by another, so you need to be aware
of the meaning of the specified options. Also some options are
meant only for decoding or encoding.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools, or by setting the value explicitly in the
<code>AVCodecContext</code> options or using the &lsquo;<tt>libavutil/opt.h</tt>&rsquo; API
for programmatic use.
</p>
<p>The list of supported options follow:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>b <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Set bitrate in bits/s. Default value is 200K.
</p>
</dd>
<dt> &lsquo;<samp>ab <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set audio bitrate (in bits/s). Default value is 128K.
</p>
</dd>
<dt> &lsquo;<samp>bt <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
tolerance specifies how far ratecontrol is willing to deviate from the
target average bitrate value. This is not related to min/max
bitrate. Lowering tolerance too much has an adverse effect on quality.
</p>
</dd>
<dt> &lsquo;<samp>flags <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>&rsquo;</dt>
<dd><p>Set generic flags.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>mv4</samp>&rsquo;</dt>
<dd><p>Use four motion vector by macroblock (mpeg4).
</p></dd>
<dt> &lsquo;<samp>qpel</samp>&rsquo;</dt>
<dd><p>Use 1/4 pel motion compensation.
</p></dd>
<dt> &lsquo;<samp>loop</samp>&rsquo;</dt>
<dd><p>Use loop filter.
</p></dd>
<dt> &lsquo;<samp>qscale</samp>&rsquo;</dt>
<dd><p>Use fixed qscale.
</p></dd>
<dt> &lsquo;<samp>gmc</samp>&rsquo;</dt>
<dd><p>Use gmc.
</p></dd>
<dt> &lsquo;<samp>mv0</samp>&rsquo;</dt>
<dd><p>Always try a mb with mv=&lt;0,0&gt;.
</p></dd>
<dt> &lsquo;<samp>input_preserved</samp>&rsquo;</dt>
<dt> &lsquo;<samp>pass1</samp>&rsquo;</dt>
<dd><p>Use internal 2pass ratecontrol in first pass mode.
</p></dd>
<dt> &lsquo;<samp>pass2</samp>&rsquo;</dt>
<dd><p>Use internal 2pass ratecontrol in second pass mode.
</p></dd>
<dt> &lsquo;<samp>gray</samp>&rsquo;</dt>
<dd><p>Only decode/encode grayscale.
</p></dd>
<dt> &lsquo;<samp>emu_edge</samp>&rsquo;</dt>
<dd><p>Do not draw edges.
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>Set error[?] variables during encoding.
</p></dd>
<dt> &lsquo;<samp>truncated</samp>&rsquo;</dt>
<dt> &lsquo;<samp>naq</samp>&rsquo;</dt>
<dd><p>Normalize adaptive quantization.
</p></dd>
<dt> &lsquo;<samp>ildct</samp>&rsquo;</dt>
<dd><p>Use interlaced DCT.
</p></dd>
<dt> &lsquo;<samp>low_delay</samp>&rsquo;</dt>
<dd><p>Force low delay.
</p></dd>
<dt> &lsquo;<samp>global_header</samp>&rsquo;</dt>
<dd><p>Place global headers in extradata instead of every keyframe.
</p></dd>
<dt> &lsquo;<samp>bitexact</samp>&rsquo;</dt>
<dd><p>Use only bitexact stuff (except (I)DCT).
</p></dd>
<dt> &lsquo;<samp>aic</samp>&rsquo;</dt>
<dd><p>Apply H263 advanced intra coding / mpeg4 ac prediction.
</p></dd>
<dt> &lsquo;<samp>cbp</samp>&rsquo;</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p></dd>
<dt> &lsquo;<samp>qprd</samp>&rsquo;</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p></dd>
<dt> &lsquo;<samp>ilme</samp>&rsquo;</dt>
<dd><p>Apply interlaced motion estimation.
</p></dd>
<dt> &lsquo;<samp>cgop</samp>&rsquo;</dt>
<dd><p>Use closed gop.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>me_method <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set motion estimation method.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>zero motion estimation (fastest)
</p></dd>
<dt> &lsquo;<samp>full</samp>&rsquo;</dt>
<dd><p>full motion estimation (slowest)
</p></dd>
<dt> &lsquo;<samp>epzs</samp>&rsquo;</dt>
<dd><p>EPZS motion estimation (default)
</p></dd>
<dt> &lsquo;<samp>esa</samp>&rsquo;</dt>
<dd><p>esa motion estimation (alias for full)
</p></dd>
<dt> &lsquo;<samp>tesa</samp>&rsquo;</dt>
<dd><p>tesa motion estimation
</p></dd>
<dt> &lsquo;<samp>dia</samp>&rsquo;</dt>
<dd><p>dia motion estimation (alias for epzs)
</p></dd>
<dt> &lsquo;<samp>log</samp>&rsquo;</dt>
<dd><p>log motion estimation
</p></dd>
<dt> &lsquo;<samp>phods</samp>&rsquo;</dt>
<dd><p>phods motion estimation
</p></dd>
<dt> &lsquo;<samp>x1</samp>&rsquo;</dt>
<dd><p>X1 motion estimation
</p></dd>
<dt> &lsquo;<samp>hex</samp>&rsquo;</dt>
<dd><p>hex motion estimation
</p></dd>
<dt> &lsquo;<samp>umh</samp>&rsquo;</dt>
<dd><p>umh motion estimation
</p></dd>
<dt> &lsquo;<samp>iter</samp>&rsquo;</dt>
<dd><p>iter motion estimation
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>extradata_size <var>integer</var></samp>&rsquo;</dt>
<dd><p>Set extradata size.
</p>
</dd>
<dt> &lsquo;<samp>time_base <var>rational number</var></samp>&rsquo;</dt>
<dd><p>Set codec time base.
</p>
<p>It is the fundamental unit of time (in seconds) in terms of which
frame timestamps are represented. For fixed-fps content, timebase
should be <code>1 / frame_rate</code> and timestamp increments should be
identically 1.
</p>
</dd>
<dt> &lsquo;<samp>g <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set the group of picture size. Default value is 12.
</p>
</dd>
<dt> &lsquo;<samp>ar <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set audio sampling rate (in Hz).
</p>
</dd>
<dt> &lsquo;<samp>ac <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set number of audio channels.
</p>
</dd>
<dt> &lsquo;<samp>cutoff <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set cutoff bandwidth.
</p>
</dd>
<dt> &lsquo;<samp>frame_size <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set audio frame size.
</p>
<p>Each submitted frame except the last must contain exactly frame_size
samples per channel. May be 0 when the codec has
CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not
restricted. It is set by some decoders to indicate constant frame
size.
</p>
</dd>
<dt> &lsquo;<samp>frame_number <var>integer</var></samp>&rsquo;</dt>
<dd><p>Set the frame number.
</p>
</dd>
<dt> &lsquo;<samp>delay <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>qcomp <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set video quantizer scale compression (VBR). It is used as a constant
in the ratecontrol equation. Recommended range for default rc_eq:
0.0-1.0.
</p>
</dd>
<dt> &lsquo;<samp>qblur <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set video quantizer scale blur (VBR).
</p>
</dd>
<dt> &lsquo;<samp>qmin <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set min video quantizer scale (VBR). Must be included between -1 and
69, default value is 2.
</p>
</dd>
<dt> &lsquo;<samp>qmax <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set max video quantizer scale (VBR). Must be included between -1 and
1024, default value is 31.
</p>
</dd>
<dt> &lsquo;<samp>qdiff <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set max difference between the quantizer scale (VBR).
</p>
</dd>
<dt> &lsquo;<samp>bf <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set max number of B frames between non-B-frames.
</p>
<p>Must be an integer between -1 and 16. 0 means that B-frames are
disabled. If a value of -1 is used, it will choose an automatic value
depending on the encoder.
</p>
<p>Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>b_qfactor <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set qp factor between P and B frames.
</p>
</dd>
<dt> &lsquo;<samp>rc_strategy <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set ratecontrol method.
</p>
</dd>
<dt> &lsquo;<samp>b_strategy <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set strategy to choose between I/P/B-frames.
</p>
</dd>
<dt> &lsquo;<samp>ps <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set RTP payload size in bytes.
</p>
</dd>
<dt> &lsquo;<samp>mv_bits <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>header_bits <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>i_tex_bits <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>p_tex_bits <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>i_count <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>p_count <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>skip_count <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>misc_bits <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>frame_bits <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>codec_tag <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>bug <var>flags</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Workaround not auto detected encoder bugs.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>autodetect</samp>&rsquo;</dt>
<dt> &lsquo;<samp>old_msmpeg4</samp>&rsquo;</dt>
<dd><p>some old lavc generated msmpeg4v3 files (no autodetection)
</p></dd>
<dt> &lsquo;<samp>xvid_ilace</samp>&rsquo;</dt>
<dd><p>Xvid interlacing bug (autodetected if fourcc==XVIX)
</p></dd>
<dt> &lsquo;<samp>ump4</samp>&rsquo;</dt>
<dd><p>(autodetected if fourcc==UMP4)
</p></dd>
<dt> &lsquo;<samp>no_padding</samp>&rsquo;</dt>
<dd><p>padding bug (autodetected)
</p></dd>
<dt> &lsquo;<samp>amv</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ac_vlc</samp>&rsquo;</dt>
<dd><p>illegal vlc bug (autodetected per fourcc)
</p></dd>
<dt> &lsquo;<samp>qpel_chroma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>std_qpel</samp>&rsquo;</dt>
<dd><p>old standard qpel (autodetected per fourcc/version)
</p></dd>
<dt> &lsquo;<samp>qpel_chroma2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>direct_blocksize</samp>&rsquo;</dt>
<dd><p>direct-qpel-blocksize bug (autodetected per fourcc/version)
</p></dd>
<dt> &lsquo;<samp>edge</samp>&rsquo;</dt>
<dd><p>edge padding bug (autodetected per fourcc/version)
</p></dd>
<dt> &lsquo;<samp>hpel_chroma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dc_clip</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ms</samp>&rsquo;</dt>
<dd><p>Workaround various bugs in microsoft broken decoders.
</p></dd>
<dt> &lsquo;<samp>trunc</samp>&rsquo;</dt>
<dd><p>trancated frames
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>lelim <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set single coefficient elimination threshold for luminance (negative
values also consider DC coefficient).
</p>
</dd>
<dt> &lsquo;<samp>celim <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set single coefficient elimination threshold for chrominance (negative
values also consider dc coefficient)
</p>
</dd>
<dt> &lsquo;<samp>strict <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Specify how strictly to follow the standards.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>very</samp>&rsquo;</dt>
<dd><p>strictly conform to a older more strict version of the spec or reference software
</p></dd>
<dt> &lsquo;<samp>strict</samp>&rsquo;</dt>
<dd><p>strictly conform to all the things in the spec no matter what consequences
</p></dd>
<dt> &lsquo;<samp>normal</samp>&rsquo;</dt>
<dt> &lsquo;<samp>unofficial</samp>&rsquo;</dt>
<dd><p>allow unofficial extensions
</p></dd>
<dt> &lsquo;<samp>experimental</samp>&rsquo;</dt>
<dd><p>allow non standardized experimental things, experimental
(unfinished/work in progress/not well tested) decoders and encoders.
Note: experimental decoders can pose a security risk, do not use this for
decoding untrusted input.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>b_qoffset <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set QP offset between P and B frames.
</p>
</dd>
<dt> &lsquo;<samp>err_detect <var>flags</var> (<em>decoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Set error detection flags.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>crccheck</samp>&rsquo;</dt>
<dd><p>verify embedded CRCs
</p></dd>
<dt> &lsquo;<samp>bitstream</samp>&rsquo;</dt>
<dd><p>detect bitstream specification deviations
</p></dd>
<dt> &lsquo;<samp>buffer</samp>&rsquo;</dt>
<dd><p>detect improper bitstream length
</p></dd>
<dt> &lsquo;<samp>explode</samp>&rsquo;</dt>
<dd><p>abort decoding on minor error detection
</p></dd>
<dt> &lsquo;<samp>careful</samp>&rsquo;</dt>
<dd><p>consider things that violate the spec and have not been seen in the wild as errors
</p></dd>
<dt> &lsquo;<samp>compliant</samp>&rsquo;</dt>
<dd><p>consider all spec non compliancies as errors
</p></dd>
<dt> &lsquo;<samp>aggressive</samp>&rsquo;</dt>
<dd><p>consider things that a sane encoder should not do as an error
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>has_b_frames <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>block_align <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>mpeg_quant <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Use MPEG quantizers instead of H.263.
</p>
</dd>
<dt> &lsquo;<samp>qsquish <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>How to keep quantizer between qmin and qmax (0 = clip, 1 = use
differentiable function).
</p>
</dd>
<dt> &lsquo;<samp>rc_qmod_amp <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set experimental quantizer modulation.
</p>
</dd>
<dt> &lsquo;<samp>rc_qmod_freq <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set experimental quantizer modulation.
</p>
</dd>
<dt> &lsquo;<samp>rc_override_count <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>rc_eq <var>string</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set rate control equation. When computing the expression, besides the
standard functions defined in the section &rsquo;Expression Evaluation&rsquo;, the
following functions are available: bits2qp(bits), qp2bits(qp). Also
the following constants are available: iTex pTex tex mv fCode iCount
mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex
avgTex.
</p>
</dd>
<dt> &lsquo;<samp>maxrate <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Set max bitrate tolerance (in bits/s). Requires bufsize to be set.
</p>
</dd>
<dt> &lsquo;<samp>minrate <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR
encode. It is of little use elsewise.
</p>
</dd>
<dt> &lsquo;<samp>bufsize <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Set ratecontrol buffer size (in bits).
</p>
</dd>
<dt> &lsquo;<samp>rc_buf_aggressivity <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Currently useless.
</p>
</dd>
<dt> &lsquo;<samp>i_qfactor <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set QP factor between P and I frames.
</p>
</dd>
<dt> &lsquo;<samp>i_qoffset <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set QP offset between P and I frames.
</p>
</dd>
<dt> &lsquo;<samp>rc_init_cplx <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set initial complexity for 1-pass encoding.
</p>
</dd>
<dt> &lsquo;<samp>dct <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set DCT algorithm.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>autoselect a good one (default)
</p></dd>
<dt> &lsquo;<samp>fastint</samp>&rsquo;</dt>
<dd><p>fast integer
</p></dd>
<dt> &lsquo;<samp>int</samp>&rsquo;</dt>
<dd><p>accurate integer
</p></dd>
<dt> &lsquo;<samp>mmx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>altivec</samp>&rsquo;</dt>
<dt> &lsquo;<samp>faan</samp>&rsquo;</dt>
<dd><p>floating point AAN DCT
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>lumi_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Compress bright areas stronger than medium ones.
</p>
</dd>
<dt> &lsquo;<samp>tcplx_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set temporal complexity masking.
</p>
</dd>
<dt> &lsquo;<samp>scplx_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set spatial complexity masking.
</p>
</dd>
<dt> &lsquo;<samp>p_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set inter masking.
</p>
</dd>
<dt> &lsquo;<samp>dark_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Compress dark areas stronger than medium ones.
</p>
</dd>
<dt> &lsquo;<samp>idct <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Select IDCT implementation.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dt> &lsquo;<samp>int</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simple</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simplemmx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>arm</samp>&rsquo;</dt>
<dt> &lsquo;<samp>altivec</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sh4</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simplearm</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simplearmv5te</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simplearmv6</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simpleneon</samp>&rsquo;</dt>
<dt> &lsquo;<samp>simplealpha</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ipp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>xvidmmx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>faani</samp>&rsquo;</dt>
<dd><p>floating point AAN IDCT
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>slice_count <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>ec <var>flags</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set error concealment strategy.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>guess_mvs</samp>&rsquo;</dt>
<dd><p>iterative motion vector (MV) search (slow)
</p></dd>
<dt> &lsquo;<samp>deblock</samp>&rsquo;</dt>
<dd><p>use strong deblock filter for damaged MBs
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>bits_per_coded_sample <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>pred <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set prediction method.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>left</samp>&rsquo;</dt>
<dt> &lsquo;<samp>plane</samp>&rsquo;</dt>
<dt> &lsquo;<samp>median</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>aspect <var>rational number</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set sample aspect ratio.
</p>
</dd>
<dt> &lsquo;<samp>debug <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>&rsquo;</dt>
<dd><p>Print specific debug info.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>pict</samp>&rsquo;</dt>
<dd><p>picture info
</p></dd>
<dt> &lsquo;<samp>rc</samp>&rsquo;</dt>
<dd><p>rate control
</p></dd>
<dt> &lsquo;<samp>bitstream</samp>&rsquo;</dt>
<dt> &lsquo;<samp>mb_type</samp>&rsquo;</dt>
<dd><p>macroblock (MB) type
</p></dd>
<dt> &lsquo;<samp>qp</samp>&rsquo;</dt>
<dd><p>per-block quantization parameter (QP)
</p></dd>
<dt> &lsquo;<samp>mv</samp>&rsquo;</dt>
<dd><p>motion vector
</p></dd>
<dt> &lsquo;<samp>dct_coeff</samp>&rsquo;</dt>
<dt> &lsquo;<samp>skip</samp>&rsquo;</dt>
<dt> &lsquo;<samp>startcode</samp>&rsquo;</dt>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dt> &lsquo;<samp>er</samp>&rsquo;</dt>
<dd><p>error recognition
</p></dd>
<dt> &lsquo;<samp>mmco</samp>&rsquo;</dt>
<dd><p>memory management control operations (H.264)
</p></dd>
<dt> &lsquo;<samp>bugs</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vis_qp</samp>&rsquo;</dt>
<dd><p>visualize quantization parameter (QP), lower QP are tinted greener
</p></dd>
<dt> &lsquo;<samp>vis_mb_type</samp>&rsquo;</dt>
<dd><p>visualize block types
</p></dd>
<dt> &lsquo;<samp>buffers</samp>&rsquo;</dt>
<dd><p>picture buffer allocations
</p></dd>
<dt> &lsquo;<samp>thread_ops</samp>&rsquo;</dt>
<dd><p>threading operations
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>vismv <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Visualize motion vectors (MVs).
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>pf</samp>&rsquo;</dt>
<dd><p>forward predicted MVs of P-frames
</p></dd>
<dt> &lsquo;<samp>bf</samp>&rsquo;</dt>
<dd><p>forward predicted MVs of B-frames
</p></dd>
<dt> &lsquo;<samp>bb</samp>&rsquo;</dt>
<dd><p>backward predicted MVs of B-frames
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>cmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set full pel me compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>sad</samp>&rsquo;</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dd><p>sum of squared errors
</p></dd>
<dt> &lsquo;<samp>satd</samp>&rsquo;</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt> &lsquo;<samp>dct</samp>&rsquo;</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt> &lsquo;<samp>bit</samp>&rsquo;</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>0
</p></dd>
<dt> &lsquo;<samp>vsad</samp>&rsquo;</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt> &lsquo;<samp>vsse</samp>&rsquo;</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt> &lsquo;<samp>nsse</samp>&rsquo;</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt> &lsquo;<samp>w53</samp>&rsquo;</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>w97</samp>&rsquo;</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>dctmax</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>subcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set sub pel me compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>sad</samp>&rsquo;</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dd><p>sum of squared errors
</p></dd>
<dt> &lsquo;<samp>satd</samp>&rsquo;</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt> &lsquo;<samp>dct</samp>&rsquo;</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt> &lsquo;<samp>bit</samp>&rsquo;</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>0
</p></dd>
<dt> &lsquo;<samp>vsad</samp>&rsquo;</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt> &lsquo;<samp>vsse</samp>&rsquo;</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt> &lsquo;<samp>nsse</samp>&rsquo;</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt> &lsquo;<samp>w53</samp>&rsquo;</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>w97</samp>&rsquo;</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>dctmax</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>mbcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set macroblock compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>sad</samp>&rsquo;</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dd><p>sum of squared errors
</p></dd>
<dt> &lsquo;<samp>satd</samp>&rsquo;</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt> &lsquo;<samp>dct</samp>&rsquo;</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt> &lsquo;<samp>bit</samp>&rsquo;</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>0
</p></dd>
<dt> &lsquo;<samp>vsad</samp>&rsquo;</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt> &lsquo;<samp>vsse</samp>&rsquo;</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt> &lsquo;<samp>nsse</samp>&rsquo;</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt> &lsquo;<samp>w53</samp>&rsquo;</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>w97</samp>&rsquo;</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>dctmax</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>ildctcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set interlaced dct compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>sad</samp>&rsquo;</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dd><p>sum of squared errors
</p></dd>
<dt> &lsquo;<samp>satd</samp>&rsquo;</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt> &lsquo;<samp>dct</samp>&rsquo;</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt> &lsquo;<samp>bit</samp>&rsquo;</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>0
</p></dd>
<dt> &lsquo;<samp>vsad</samp>&rsquo;</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt> &lsquo;<samp>vsse</samp>&rsquo;</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt> &lsquo;<samp>nsse</samp>&rsquo;</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt> &lsquo;<samp>w53</samp>&rsquo;</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>w97</samp>&rsquo;</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>dctmax</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>dia_size <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set diamond type &amp; size for motion estimation.
</p>
</dd>
<dt> &lsquo;<samp>last_pred <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set amount of motion predictors from the previous frame.
</p>
</dd>
<dt> &lsquo;<samp>preme <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set pre motion estimation.
</p>
</dd>
<dt> &lsquo;<samp>precmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set pre motion estimation compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>sad</samp>&rsquo;</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dd><p>sum of squared errors
</p></dd>
<dt> &lsquo;<samp>satd</samp>&rsquo;</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt> &lsquo;<samp>dct</samp>&rsquo;</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt> &lsquo;<samp>bit</samp>&rsquo;</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>0
</p></dd>
<dt> &lsquo;<samp>vsad</samp>&rsquo;</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt> &lsquo;<samp>vsse</samp>&rsquo;</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt> &lsquo;<samp>nsse</samp>&rsquo;</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt> &lsquo;<samp>w53</samp>&rsquo;</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>w97</samp>&rsquo;</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>dctmax</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>pre_dia_size <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set diamond type &amp; size for motion estimation pre-pass.
</p>
</dd>
<dt> &lsquo;<samp>subq <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set sub pel motion estimation quality.
</p>
</dd>
<dt> &lsquo;<samp>dtg_active_format <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>me_range <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set limit motion vectors range (1023 for DivX player).
</p>
</dd>
<dt> &lsquo;<samp>ibias <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set intra quant bias.
</p>
</dd>
<dt> &lsquo;<samp>pbias <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set inter quant bias.
</p>
</dd>
<dt> &lsquo;<samp>color_table_id <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>global_quality <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>coder <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>vlc</samp>&rsquo;</dt>
<dd><p>variable length coder / huffman coder
</p></dd>
<dt> &lsquo;<samp>ac</samp>&rsquo;</dt>
<dd><p>arithmetic coder
</p></dd>
<dt> &lsquo;<samp>raw</samp>&rsquo;</dt>
<dd><p>raw (no encoding)
</p></dd>
<dt> &lsquo;<samp>rle</samp>&rsquo;</dt>
<dd><p>run-length coder
</p></dd>
<dt> &lsquo;<samp>deflate</samp>&rsquo;</dt>
<dd><p>deflate-based coder
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>context <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set context model.
</p>
</dd>
<dt> &lsquo;<samp>slice_flags <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>xvmc_acceleration <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>mbd <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set macroblock decision algorithm (high quality mode).
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>simple</samp>&rsquo;</dt>
<dd><p>use mbcmp (default)
</p></dd>
<dt> &lsquo;<samp>bits</samp>&rsquo;</dt>
<dd><p>use fewest bits
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>use best rate distortion
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>stream_codec_tag <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>sc_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set scene change threshold.
</p>
</dd>
<dt> &lsquo;<samp>lmin <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set min lagrange factor (VBR).
</p>
</dd>
<dt> &lsquo;<samp>lmax <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set max lagrange factor (VBR).
</p>
</dd>
<dt> &lsquo;<samp>nr <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set noise reduction.
</p>
</dd>
<dt> &lsquo;<samp>rc_init_occupancy <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set number of bits which should be loaded into the rc buffer before
decoding starts.
</p>
</dd>
<dt> &lsquo;<samp>flags2 <var>flags</var> (<em>decoding/encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>fast</samp>&rsquo;</dt>
<dd><p>Allow non spec compliant speedup tricks.
</p></dd>
<dt> &lsquo;<samp>sgop</samp>&rsquo;</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p></dd>
<dt> &lsquo;<samp>noout</samp>&rsquo;</dt>
<dd><p>Skip bitstream encoding.
</p></dd>
<dt> &lsquo;<samp>ignorecrop</samp>&rsquo;</dt>
<dd><p>Ignore cropping information from sps.
</p></dd>
<dt> &lsquo;<samp>local_header</samp>&rsquo;</dt>
<dd><p>Place global headers at every keyframe instead of in extradata.
</p></dd>
<dt> &lsquo;<samp>chunks</samp>&rsquo;</dt>
<dd><p>Frame data might be split into multiple chunks.
</p></dd>
<dt> &lsquo;<samp>showall</samp>&rsquo;</dt>
<dd><p>Show all frames before the first keyframe.
</p></dd>
<dt> &lsquo;<samp>skiprd</samp>&rsquo;</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>error <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>qns <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p>
</dd>
<dt> &lsquo;<samp>threads <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>detect a good number of threads
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>me_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set motion estimation threshold.
</p>
</dd>
<dt> &lsquo;<samp>mb_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set macroblock threshold.
</p>
</dd>
<dt> &lsquo;<samp>dc <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set intra_dc_precision.
</p>
</dd>
<dt> &lsquo;<samp>nssew <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set nsse weight.
</p>
</dd>
<dt> &lsquo;<samp>skip_top <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set number of macroblock rows at the top which are skipped.
</p>
</dd>
<dt> &lsquo;<samp>skip_bottom <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set number of macroblock rows at the bottom which are skipped.
</p>
</dd>
<dt> &lsquo;<samp>profile <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>unknown</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_main</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_low</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_ssr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_ltp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_he</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_he_v2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_ld</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aac_eld</samp>&rsquo;</dt>
<dt> &lsquo;<samp>mpeg2_aac_low</samp>&rsquo;</dt>
<dt> &lsquo;<samp>mpeg2_aac_he</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dts</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dts_es</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dts_96_24</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dts_hd_hra</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dts_hd_ma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>level <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>unknown</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>lowres <var>integer</var> (<em>decoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.
</p>
</dd>
<dt> &lsquo;<samp>skip_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set frame skip threshold.
</p>
</dd>
<dt> &lsquo;<samp>skip_factor <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set frame skip factor.
</p>
</dd>
<dt> &lsquo;<samp>skip_exp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set frame skip exponent.
Negative values behave identical to the corresponding positive ones, except
that the score is normalized.
Positive values exist primarly for compatibility reasons and are not so useful.
</p>
</dd>
<dt> &lsquo;<samp>skipcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set frame skip compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>sad</samp>&rsquo;</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt> &lsquo;<samp>sse</samp>&rsquo;</dt>
<dd><p>sum of squared errors
</p></dd>
<dt> &lsquo;<samp>satd</samp>&rsquo;</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt> &lsquo;<samp>dct</samp>&rsquo;</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt> &lsquo;<samp>psnr</samp>&rsquo;</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt> &lsquo;<samp>bit</samp>&rsquo;</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt> &lsquo;<samp>rd</samp>&rsquo;</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>0
</p></dd>
<dt> &lsquo;<samp>vsad</samp>&rsquo;</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt> &lsquo;<samp>vsse</samp>&rsquo;</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt> &lsquo;<samp>nsse</samp>&rsquo;</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt> &lsquo;<samp>w53</samp>&rsquo;</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>w97</samp>&rsquo;</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt> &lsquo;<samp>dctmax</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>border_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Increase the quantizer for macroblocks close to borders.
</p>
</dd>
<dt> &lsquo;<samp>mblmin <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set min macroblock lagrange factor (VBR).
</p>
</dd>
<dt> &lsquo;<samp>mblmax <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set max macroblock lagrange factor (VBR).
</p>
</dd>
<dt> &lsquo;<samp>mepc <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set motion estimation bitrate penalty compensation (1.0 = 256).
</p>
</dd>
<dt> &lsquo;<samp>skip_loop_filter <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>skip_idct <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>skip_frame <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd>
<p>Make decoder discard processing depending on the frame type selected
by the option value.
</p>
<p>&lsquo;<samp>skip_loop_filter</samp>&rsquo; skips frame loop filtering, &lsquo;<samp>skip_idct</samp>&rsquo;
skips frame IDCT/dequantization, &lsquo;<samp>skip_frame</samp>&rsquo; skips decoding.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>Discard no frame.
</p>
</dd>
<dt> &lsquo;<samp>default</samp>&rsquo;</dt>
<dd><p>Discard useless frames like 0-sized frames.
</p>
</dd>
<dt> &lsquo;<samp>noref</samp>&rsquo;</dt>
<dd><p>Discard all non-reference frames.
</p>
</dd>
<dt> &lsquo;<samp>bidir</samp>&rsquo;</dt>
<dd><p>Discard all bidirectional frames.
</p>
</dd>
<dt> &lsquo;<samp>nokey</samp>&rsquo;</dt>
<dd><p>Discard all frames excepts keyframes.
</p>
</dd>
<dt> &lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Discard all frames.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>default</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>bidir_refine <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Refine the two motion vectors used in bidirectional macroblocks.
</p>
</dd>
<dt> &lsquo;<samp>brd_scale <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Downscale frames for dynamic B-frame decision.
</p>
</dd>
<dt> &lsquo;<samp>keyint_min <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set minimum interval between IDR-frames.
</p>
</dd>
<dt> &lsquo;<samp>refs <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set reference frames to consider for motion compensation.
</p>
</dd>
<dt> &lsquo;<samp>chromaoffset <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set chroma qp offset from luma.
</p>
</dd>
<dt> &lsquo;<samp>trellis <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dd><p>Set rate-distortion optimal quantization.
</p>
</dd>
<dt> &lsquo;<samp>sc_factor <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set value multiplied by qscale for each frame and added to
scene_change_score.
</p>
</dd>
<dt> &lsquo;<samp>mv0_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>b_sensitivity <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Adjust sensitivity of b_frame_strategy 1.
</p>
</dd>
<dt> &lsquo;<samp>compression_level <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>min_prediction_order <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>max_prediction_order <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>timecode_frame_start <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set GOP timecode frame start number, in non drop frame format.
</p>
</dd>
<dt> &lsquo;<samp>request_channels <var>integer</var> (<em>decoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set desired number of audio channels.
</p>
</dd>
<dt> &lsquo;<samp>bits_per_raw_sample <var>integer</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>channel_layout <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p></dd>
<dt> &lsquo;<samp>request_channel_layout <var>integer</var> (<em>decoding,audio</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p></dd>
<dt> &lsquo;<samp>rc_max_vbv_use <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>rc_min_vbv_use <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ticks_per_frame <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>color_primaries <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>color_trc <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>colorspace <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>color_range <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_sample_location <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>log_level_offset <var>integer</var></samp>&rsquo;</dt>
<dd><p>Set the log level offset.
</p>
</dd>
<dt> &lsquo;<samp>slices <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Number of slices, used in parallelized encoding.
</p>
</dd>
<dt> &lsquo;<samp>thread_type <var>flags</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Select multithreading type.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>slice</samp>&rsquo;</dt>
<dt> &lsquo;<samp>frame</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>audio_service_type <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set audio service type.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>ma</samp>&rsquo;</dt>
<dd><p>Main Audio Service
</p></dd>
<dt> &lsquo;<samp>ef</samp>&rsquo;</dt>
<dd><p>Effects
</p></dd>
<dt> &lsquo;<samp>vi</samp>&rsquo;</dt>
<dd><p>Visually Impaired
</p></dd>
<dt> &lsquo;<samp>hi</samp>&rsquo;</dt>
<dd><p>Hearing Impaired
</p></dd>
<dt> &lsquo;<samp>di</samp>&rsquo;</dt>
<dd><p>Dialogue
</p></dd>
<dt> &lsquo;<samp>co</samp>&rsquo;</dt>
<dd><p>Commentary
</p></dd>
<dt> &lsquo;<samp>em</samp>&rsquo;</dt>
<dd><p>Emergency
</p></dd>
<dt> &lsquo;<samp>vo</samp>&rsquo;</dt>
<dd><p>Voice Over
</p></dd>
<dt> &lsquo;<samp>ka</samp>&rsquo;</dt>
<dd><p>Karaoke
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>request_sample_fmt <var>sample_fmt</var> (<em>decoding,audio</em>)</samp>&rsquo;</dt>
<dd><p>Set sample format audio decoders should prefer. Default value is
<code>none</code>.
</p>
</dd>
<dt> &lsquo;<samp>pkt_timebase <var>rational number</var></samp>&rsquo;</dt>
<dt> &lsquo;<samp>sub_charenc <var>encoding</var> (<em>decoding,subtitles</em>)</samp>&rsquo;</dt>
<dd><p>Set the input subtitles character encoding.
</p>
</dd>
<dt> &lsquo;<samp>field_order <var>field_order</var> (<em>video</em>)</samp>&rsquo;</dt>
<dd><p>Set/override the field order of the video.
Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>progressive</samp>&rsquo;</dt>
<dd><p>Progressive video
</p></dd>
<dt> &lsquo;<samp>tt</samp>&rsquo;</dt>
<dd><p>Interlaced video, top field coded and displayed first
</p></dd>
<dt> &lsquo;<samp>bb</samp>&rsquo;</dt>
<dd><p>Interlaced video, bottom field coded and displayed first
</p></dd>
<dt> &lsquo;<samp>tb</samp>&rsquo;</dt>
<dd><p>Interlaced video, top coded first, bottom displayed first
</p></dd>
<dt> &lsquo;<samp>bt</samp>&rsquo;</dt>
<dd><p>Interlaced video, bottom coded first, top displayed first
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>skip_alpha <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
<dd><p>Set to 1 to disable processing alpha (transparency). This works like the
&lsquo;<samp>gray</samp>&rsquo; flag in the &lsquo;<samp>flags</samp>&rsquo; option which skips chroma information
instead of alpha. Default is 0.
</p></dd>
</dl>
<a name="Decoders"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Decoders">8. Decoders</a></h1>
<p>Decoders are configured elements in FFmpeg which allow the decoding of
multimedia streams.
</p>
<p>When you configure your FFmpeg build, all the supported native decoders
are enabled by default. Decoders requiring an external library must be enabled
manually via the corresponding <code>--enable-lib</code> option. You can list all
available decoders using the configure option <code>--list-decoders</code>.
</p>
<p>You can disable all the decoders with the configure option
<code>--disable-decoders</code> and selectively enable / disable single decoders
with the options <code>--enable-decoder=<var>DECODER</var></code> /
<code>--disable-decoder=<var>DECODER</var></code>.
</p>
<p>The option <code>-decoders</code> of the ff* tools will display the list of
enabled decoders.
</p>
<a name="Video-Decoders"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Video-Decoders">9. Video Decoders</a></h1>
<p>A description of some of the currently available video decoders
follows.
</p>
<a name="rawvideo-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rawvideo-1">9.1 rawvideo</a></h2>
<p>Raw video decoder.
</p>
<p>This decoder decodes rawvideo streams.
</p>
<a name="Options-12"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-12">9.1.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>top <var>top_field_first</var></samp>&rsquo;</dt>
<dd><p>Specify the assumed field type of the input video.
</p><dl compact="compact">
<dt> &lsquo;<samp>-1</samp>&rsquo;</dt>
<dd><p>the video is assumed to be progressive (default)
</p></dd>
<dt> &lsquo;<samp>0</samp>&rsquo;</dt>
<dd><p>bottom-field-first is assumed
</p></dd>
<dt> &lsquo;<samp>1</samp>&rsquo;</dt>
<dd><p>top-field-first is assumed
</p></dd>
</dl>
</dd>
</dl>
<a name="Audio-Decoders"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Audio-Decoders">10. Audio Decoders</a></h1>
<p>A description of some of the currently available audio decoders
follows.
</p>
<a name="ac3"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ac3">10.1 ac3</a></h2>
<p>AC-3 audio decoder.
</p>
<p>This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as well as
the undocumented RealAudio 3 (a.k.a. dnet).
</p>
<a name="AC_002d3-Decoder-Options"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-AC_002d3-Decoder-Options">10.1.1 AC-3 Decoder Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>-drc_scale <var>value</var></samp>&rsquo;</dt>
<dd><p>Dynamic Range Scale Factor. The factor to apply to dynamic range values
from the AC-3 stream. This factor is applied exponentially.
There are 3 notable scale factor ranges:
</p><dl compact="compact">
<dt> &lsquo;<samp>drc_scale == 0</samp>&rsquo;</dt>
<dd><p>DRC disabled. Produces full range audio.
</p></dd>
<dt> &lsquo;<samp>0 &lt; drc_scale &lt;= 1</samp>&rsquo;</dt>
<dd><p>DRC enabled. Applies a fraction of the stream DRC value.
Audio reproduction is between full range and full compression.
</p></dd>
<dt> &lsquo;<samp>drc_scale &gt; 1</samp>&rsquo;</dt>
<dd><p>DRC enabled. Applies drc_scale asymmetrically.
Loud sounds are fully compressed. Soft sounds are enhanced.
</p></dd>
</dl>
</dd>
</dl>
<a name="ffwavesynth"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ffwavesynth">10.2 ffwavesynth</a></h2>
<p>Internal wave synthetizer.
</p>
<p>This decoder generates wave patterns according to predefined sequences. Its
use is purely internal and the format of the data it accepts is not publicly
documented.
</p>
<a name="libcelt"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libcelt">10.3 libcelt</a></h2>
<p>libcelt decoder wrapper.
</p>
<p>libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.
Requires the presence of the libcelt headers and library during configuration.
You need to explicitly configure the build with <code>--enable-libcelt</code>.
</p>
<a name="libgsm"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libgsm">10.4 libgsm</a></h2>
<p>libgsm decoder wrapper.
</p>
<p>libgsm allows libavcodec to decode the GSM full rate audio codec. Requires
the presence of the libgsm headers and library during configuration. You need
to explicitly configure the build with <code>--enable-libgsm</code>.
</p>
<p>This decoder supports both the ordinary GSM and the Microsoft variant.
</p>
<a name="libilbc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libilbc">10.5 libilbc</a></h2>
<p>libilbc decoder wrapper.
</p>
<p>libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC)
audio codec. Requires the presence of the libilbc headers and library during
configuration. You need to explicitly configure the build with
<code>--enable-libilbc</code>.
</p>
<a name="Options-14"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-14">10.5.1 Options</a></h3>
<p>The following option is supported by the libilbc wrapper.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>enhance</samp>&rsquo;</dt>
<dd>
<p>Enable the enhancement of the decoded audio when set to 1. The default
value is 0 (disabled).
</p>
</dd>
</dl>
<a name="libopencore_002damrnb"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libopencore_002damrnb">10.6 libopencore-amrnb</a></h2>
<p>libopencore-amrnb decoder wrapper.
</p>
<p>libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
Narrowband audio codec. Using it requires the presence of the
libopencore-amrnb headers and library during configuration. You need to
explicitly configure the build with <code>--enable-libopencore-amrnb</code>.
</p>
<p>An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
without this library.
</p>
<a name="libopencore_002damrwb"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libopencore_002damrwb">10.7 libopencore-amrwb</a></h2>
<p>libopencore-amrwb decoder wrapper.
</p>
<p>libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
Wideband audio codec. Using it requires the presence of the
libopencore-amrwb headers and library during configuration. You need to
explicitly configure the build with <code>--enable-libopencore-amrwb</code>.
</p>
<p>An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
without this library.
</p>
<a name="libopus"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libopus">10.8 libopus</a></h2>
<p>libopus decoder wrapper.
</p>
<p>libopus allows libavcodec to decode the Opus Interactive Audio Codec.
Requires the presence of the libopus headers and library during
configuration. You need to explicitly configure the build with
<code>--enable-libopus</code>.
</p>
<a name="Subtitles-Decoders"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Subtitles-Decoders">11. Subtitles Decoders</a></h1>
<a name="dvdsub"></a>
<h2 class="section"><a href="ffplay-all.html#toc-dvdsub">11.1 dvdsub</a></h2>
<p>This codec decodes the bitmap subtitles used in DVDs; the same subtitles can
also be found in VobSub file pairs and in some Matroska files.
</p>
<a name="Options-2"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-2">11.1.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>palette</samp>&rsquo;</dt>
<dd><p>Specify the global palette used by the bitmaps. When stored in VobSub, the
palette is normally specified in the index file; in Matroska, the palette is
stored in the codec extra-data in the same format as in VobSub. In DVDs, the
palette is stored in the IFO file, and therefore not available when reading
from dumped VOB files.
</p>
<p>The format for this option is a string containing 16 24-bits hexadecimal
numbers (without 0x prefix) separated by comas, for example <code>0d00ee,
ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b</code>.
</p></dd>
</dl>
<a name="libzvbi_002dteletext"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libzvbi_002dteletext">11.2 libzvbi-teletext</a></h2>
<p>Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext
subtitles. Requires the presence of the libzvbi headers and library during
configuration. You need to explicitly configure the build with
<code>--enable-libzvbi</code>.
</p>
<a name="Options-1"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-1">11.2.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>txt_page</samp>&rsquo;</dt>
<dd><p>List of teletext page numbers to decode. You may use the special * string to
match all pages. Pages that do not match the specified list are dropped.
Default value is *.
</p></dd>
<dt> &lsquo;<samp>txt_chop_top</samp>&rsquo;</dt>
<dd><p>Discards the top teletext line. Default value is 1.
</p></dd>
<dt> &lsquo;<samp>txt_format</samp>&rsquo;</dt>
<dd><p>Specifies the format of the decoded subtitles. The teletext decoder is capable
of decoding the teletext pages to bitmaps or to simple text, you should use
&quot;bitmap&quot; for teletext pages, because certain graphics and colors cannot be
expressed in simple text. You might use &quot;text&quot; for teletext based subtitles if
your application can handle simple text based subtitles. Default value is
bitmap.
</p></dd>
<dt> &lsquo;<samp>txt_left</samp>&rsquo;</dt>
<dd><p>X offset of generated bitmaps, default is 0.
</p></dd>
<dt> &lsquo;<samp>txt_top</samp>&rsquo;</dt>
<dd><p>Y offset of generated bitmaps, default is 0.
</p></dd>
<dt> &lsquo;<samp>txt_chop_spaces</samp>&rsquo;</dt>
<dd><p>Chops leading and trailing spaces and removes empty lines from the generated
text. This option is useful for teletext based subtitles where empty spaces may
be present at the start or at the end of the lines or empty lines may be
present between the subtitle lines because of double-sized teletext charactes.
Default value is 1.
</p></dd>
<dt> &lsquo;<samp>txt_duration</samp>&rsquo;</dt>
<dd><p>Sets the display duration of the decoded teletext pages or subtitles in
miliseconds. Default value is 30000 which is 30 seconds.
</p></dd>
<dt> &lsquo;<samp>txt_transparent</samp>&rsquo;</dt>
<dd><p>Force transparent background of the generated teletext bitmaps. Default value
is 0 which means an opaque (black) background.
</p></dd>
</dl>
<a name="Bitstream-Filters"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Bitstream-Filters">12. Bitstream Filters</a></h1>
<p>When you configure your FFmpeg build, all the supported bitstream
filters are enabled by default. You can list all available ones using
the configure option <code>--list-bsfs</code>.
</p>
<p>You can disable all the bitstream filters using the configure option
<code>--disable-bsfs</code>, and selectively enable any bitstream filter using
the option <code>--enable-bsf=BSF</code>, or you can disable a particular
bitstream filter using the option <code>--disable-bsf=BSF</code>.
</p>
<p>The option <code>-bsfs</code> of the ff* tools will display the list of
all the supported bitstream filters included in your build.
</p>
<p>Below is a description of the currently available bitstream filters.
</p>
<a name="aac_005fadtstoasc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aac_005fadtstoasc">12.1 aac_adtstoasc</a></h2>
<p>Convert MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration
bitstream filter.
</p>
<p>This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
ADTS header and removes the ADTS header.
</p>
<p>This is required for example when copying an AAC stream from a raw
ADTS AAC container to a FLV or a MOV/MP4 file.
</p>
<a name="chomp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-chomp">12.2 chomp</a></h2>
<p>Remove zero padding at the end of a packet.
</p>
<a name="dump_005fextra"></a>
<h2 class="section"><a href="ffplay-all.html#toc-dump_005fextra">12.3 dump_extra</a></h2>
<p>Add extradata to the beginning of the filtered packets.
</p>
<p>The additional argument specifies which packets should be filtered.
It accepts the values:
</p><dl compact="compact">
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>add extradata to all key packets, but only if <var>local_header</var> is
set in the &lsquo;<samp>flags2</samp>&rsquo; codec context field
</p>
</dd>
<dt> &lsquo;<samp>k</samp>&rsquo;</dt>
<dd><p>add extradata to all key packets
</p>
</dd>
<dt> &lsquo;<samp>e</samp>&rsquo;</dt>
<dd><p>add extradata to all packets
</p></dd>
</dl>
<p>If not specified it is assumed &lsquo;<samp>k</samp>&rsquo;.
</p>
<p>For example the following <code>ffmpeg</code> command forces a global
header (thus disabling individual packet headers) in the H.264 packets
generated by the <code>libx264</code> encoder, but corrects them by adding
the header stored in extradata to the key packets:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts
</pre></td></tr></table>
<a name="h264_005fmp4toannexb"></a>
<h2 class="section"><a href="ffplay-all.html#toc-h264_005fmp4toannexb">12.4 h264_mp4toannexb</a></h2>
<p>Convert an H.264 bitstream from length prefixed mode to start code
prefixed mode (as defined in the Annex B of the ITU-T H.264
specification).
</p>
<p>This is required by some streaming formats, typically the MPEG-2
transport stream format (&quot;mpegts&quot;).
</p>
<p>For example to remux an MP4 file containing an H.264 stream to mpegts
format with <code>ffmpeg</code>, you can use the command:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts
</pre></td></tr></table>
<a name="imx_005fdump_005fheader"></a>
<h2 class="section"><a href="ffplay-all.html#toc-imx_005fdump_005fheader">12.5 imx_dump_header</a></h2>
<a name="mjpeg2jpeg"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mjpeg2jpeg">12.6 mjpeg2jpeg</a></h2>
<p>Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.
</p>
<p>MJPEG is a video codec wherein each video frame is essentially a
JPEG image. The individual frames can be extracted without loss,
e.g. by
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg
</pre></td></tr></table>
<p>Unfortunately, these chunks are incomplete JPEG images, because
they lack the DHT segment required for decoding. Quoting from
<a href="http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml">http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml</a>:
</p>
<p>Avery Lee, writing in the rec.video.desktop newsgroup in 2001,
commented that &quot;MJPEG, or at least the MJPEG in AVIs having the
MJPG fourcc, is restricted JPEG with a fixed &ndash; and *omitted* &ndash;
Huffman table. The JPEG must be YCbCr colorspace, it must be 4:2:2,
and it must use basic Huffman encoding, not arithmetic or
progressive. . . . You can indeed extract the MJPEG frames and
decode them with a regular JPEG decoder, but you have to prepend
the DHT segment to them, or else the decoder won&rsquo;t have any idea
how to decompress the data. The exact table necessary is given in
the OpenDML spec.&quot;
</p>
<p>This bitstream filter patches the header of frames extracted from an MJPEG
stream (carrying the AVI1 header ID and lacking a DHT segment) to
produce fully qualified JPEG images.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i mjpeg-movie.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg
exiftran -i -9 frame*.jpg
ffmpeg -i frame_%d.jpg -c:v copy rotated.avi
</pre></td></tr></table>
<a name="mjpega_005fdump_005fheader"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mjpega_005fdump_005fheader">12.7 mjpega_dump_header</a></h2>
<a name="movsub"></a>
<h2 class="section"><a href="ffplay-all.html#toc-movsub">12.8 movsub</a></h2>
<a name="mp3_005fheader_005fdecompress"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mp3_005fheader_005fdecompress">12.9 mp3_header_decompress</a></h2>
<a name="noise-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-noise-1">12.10 noise</a></h2>
<a name="remove_005fextra"></a>
<h2 class="section"><a href="ffplay-all.html#toc-remove_005fextra">12.11 remove_extra</a></h2>
<a name="Format-Options"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Format-Options">13. Format Options</a></h1>
<p>The libavformat library provides some generic global options, which
can be set on all the muxers and demuxers. In addition each muxer or
demuxer may support so-called private options, which are specific for
that component.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools, or by setting the value explicitly in the
<code>AVFormatContext</code> options or using the &lsquo;<tt>libavutil/opt.h</tt>&rsquo; API
for programmatic use.
</p>
<p>The list of supported options follows:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>avioflags <var>flags</var> (<em>input/output</em>)</samp>&rsquo;</dt>
<dd><p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>direct</samp>&rsquo;</dt>
<dd><p>Reduce buffering.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>probesize <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set probing size in bytes, i.e. the size of the data to analyze to get
stream information. A higher value will allow to detect more
information in case it is dispersed into the stream, but will increase
latency. Must be an integer not lesser than 32. It is 5000000 by default.
</p>
</dd>
<dt> &lsquo;<samp>packetsize <var>integer</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd><p>Set packet size.
</p>
</dd>
<dt> &lsquo;<samp>fflags <var>flags</var> (<em>input/output</em>)</samp>&rsquo;</dt>
<dd><p>Set format flags.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>ignidx</samp>&rsquo;</dt>
<dd><p>Ignore index.
</p></dd>
<dt> &lsquo;<samp>genpts</samp>&rsquo;</dt>
<dd><p>Generate PTS.
</p></dd>
<dt> &lsquo;<samp>nofillin</samp>&rsquo;</dt>
<dd><p>Do not fill in missing values that can be exactly calculated.
</p></dd>
<dt> &lsquo;<samp>noparse</samp>&rsquo;</dt>
<dd><p>Disable AVParsers, this needs <code>+nofillin</code> too.
</p></dd>
<dt> &lsquo;<samp>igndts</samp>&rsquo;</dt>
<dd><p>Ignore DTS.
</p></dd>
<dt> &lsquo;<samp>discardcorrupt</samp>&rsquo;</dt>
<dd><p>Discard corrupted frames.
</p></dd>
<dt> &lsquo;<samp>sortdts</samp>&rsquo;</dt>
<dd><p>Try to interleave output packets by DTS.
</p></dd>
<dt> &lsquo;<samp>keepside</samp>&rsquo;</dt>
<dd><p>Do not merge side data.
</p></dd>
<dt> &lsquo;<samp>latm</samp>&rsquo;</dt>
<dd><p>Enable RTP MP4A-LATM payload.
</p></dd>
<dt> &lsquo;<samp>nobuffer</samp>&rsquo;</dt>
<dd><p>Reduce the latency introduced by optional buffering
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>seek2any <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Allow seeking to non-keyframes on demuxer level when supported if set to 1.
Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>analyzeduration <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Specify how many microseconds are analyzed to probe the input. A
higher value will allow to detect more accurate information, but will
increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
</p>
</dd>
<dt> &lsquo;<samp>cryptokey <var>hexadecimal string</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set decryption key.
</p>
</dd>
<dt> &lsquo;<samp>indexmem <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set max memory used for timestamp index (per stream).
</p>
</dd>
<dt> &lsquo;<samp>rtbufsize <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set max memory used for buffering real-time frames.
</p>
</dd>
<dt> &lsquo;<samp>fdebug <var>flags</var> (<em>input/output</em>)</samp>&rsquo;</dt>
<dd><p>Print specific debug info.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>ts</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>max_delay <var>integer</var> (<em>input/output</em>)</samp>&rsquo;</dt>
<dd><p>Set maximum muxing or demuxing delay in microseconds.
</p>
</dd>
<dt> &lsquo;<samp>fpsprobesize <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set number of frames used to probe fps.
</p>
</dd>
<dt> &lsquo;<samp>audio_preload <var>integer</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd><p>Set microseconds by which audio packets should be interleaved earlier.
</p>
</dd>
<dt> &lsquo;<samp>chunk_duration <var>integer</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd><p>Set microseconds for each chunk.
</p>
</dd>
<dt> &lsquo;<samp>chunk_size <var>integer</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd><p>Set size in bytes for each chunk.
</p>
</dd>
<dt> &lsquo;<samp>err_detect, f_err_detect <var>flags</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set error detection flags. <code>f_err_detect</code> is deprecated and
should be used only via the <code>ffmpeg</code> tool.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>crccheck</samp>&rsquo;</dt>
<dd><p>Verify embedded CRCs.
</p></dd>
<dt> &lsquo;<samp>bitstream</samp>&rsquo;</dt>
<dd><p>Detect bitstream specification deviations.
</p></dd>
<dt> &lsquo;<samp>buffer</samp>&rsquo;</dt>
<dd><p>Detect improper bitstream length.
</p></dd>
<dt> &lsquo;<samp>explode</samp>&rsquo;</dt>
<dd><p>Abort decoding on minor error detection.
</p></dd>
<dt> &lsquo;<samp>careful</samp>&rsquo;</dt>
<dd><p>Consider things that violate the spec and have not been seen in the
wild as errors.
</p></dd>
<dt> &lsquo;<samp>compliant</samp>&rsquo;</dt>
<dd><p>Consider all spec non compliancies as errors.
</p></dd>
<dt> &lsquo;<samp>aggressive</samp>&rsquo;</dt>
<dd><p>Consider things that a sane encoder should not do as an error.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>use_wallclock_as_timestamps <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Use wallclock as timestamps.
</p>
</dd>
<dt> &lsquo;<samp>avoid_negative_ts <var>integer</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt> &lsquo;<samp>make_non_negative</samp>&rsquo;</dt>
<dd><p>Shift timestamps to make them non-negative.
Also note that this affects only leading negative timestamps, and not
non-monotonic negative timestamps.
</p></dd>
<dt> &lsquo;<samp>make_zero</samp>&rsquo;</dt>
<dd><p>Shift timestamps so that the first timestamp is 0.
</p></dd>
<dt> &lsquo;<samp>auto (default)</samp>&rsquo;</dt>
<dd><p>Enables shifting when required by the target format.
</p></dd>
<dt> &lsquo;<samp>disabled</samp>&rsquo;</dt>
<dd><p>Disables shifting of timestamp.
</p></dd>
</dl>
<p>When shifting is enabled, all output timestamps are shifted by the
same amount. Audio, video, and subtitles desynching and relative
timestamp differences are preserved compared to how they would have
been without shifting.
</p>
</dd>
<dt> &lsquo;<samp>skip_initial_bytes <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Set number of bytes to skip before reading header and frames if set to 1.
Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>correct_ts_overflow <var>integer</var> (<em>input</em>)</samp>&rsquo;</dt>
<dd><p>Correct single timestamp overflows if set to 1. Default is 1.
</p>
</dd>
<dt> &lsquo;<samp>flush_packets <var>integer</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd><p>Flush the underlying I/O stream after each packet. Default 1 enables it, and
has the effect of reducing the latency; 0 disables it and may slightly
increase performance in some cases.
</p>
</dd>
<dt> &lsquo;<samp>output_ts_offset <var>offset</var> (<em>output</em>)</samp>&rsquo;</dt>
<dd><p>Set the output time offset.
</p>
<p><var>offset</var> must be a time duration specification,
see <a href="ffmpeg-utils.html#time-duration-syntax">(ffmpeg-utils)time duration syntax</a>.
</p>
<p>The offset is added by the muxer to the output timestamps.
</p>
<p>Specifying a positive offset means that the corresponding streams are
delayed bt the time duration specified in <var>offset</var>. Default value
is <code>0</code> (meaning that no offset is applied).
</p></dd>
</dl>
<p><a name="Format-stream-specifiers"></a>
</p><a name="Format-stream-specifiers-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Format-stream-specifiers-1">13.1 Format stream specifiers</a></h2>
<p>Format stream specifiers allow selection of one or more streams that
match specific properties.
</p>
<p>Possible forms of stream specifiers are:
</p><dl compact="compact">
<dt> &lsquo;<samp><var>stream_index</var></samp>&rsquo;</dt>
<dd><p>Matches the stream with this index.
</p>
</dd>
<dt> &lsquo;<samp><var>stream_type</var>[:<var>stream_index</var>]</samp>&rsquo;</dt>
<dd><p><var>stream_type</var> is one of following: &rsquo;v&rsquo; for video, &rsquo;a&rsquo; for audio,
&rsquo;s&rsquo; for subtitle, &rsquo;d&rsquo; for data, and &rsquo;t&rsquo; for attachments. If
<var>stream_index</var> is given, then it matches the stream number
<var>stream_index</var> of this type. Otherwise, it matches all streams of
this type.
</p>
</dd>
<dt> &lsquo;<samp>p:<var>program_id</var>[:<var>stream_index</var>]</samp>&rsquo;</dt>
<dd><p>If <var>stream_index</var> is given, then it matches the stream with number
<var>stream_index</var> in the program with the id
<var>program_id</var>. Otherwise, it matches all streams in the program.
</p>
</dd>
<dt> &lsquo;<samp>#<var>stream_id</var></samp>&rsquo;</dt>
<dd><p>Matches the stream by a format-specific ID.
</p></dd>
</dl>
<p>The exact semantics of stream specifiers is defined by the
<code>avformat_match_stream_specifier()</code> function declared in the
&lsquo;<tt>libavformat/avformat.h</tt>&rsquo; header.
</p>
<a name="Demuxers"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Demuxers">14. Demuxers</a></h1>
<p>Demuxers are configured elements in FFmpeg that can read the
multimedia streams from a particular type of file.
</p>
<p>When you configure your FFmpeg build, all the supported demuxers
are enabled by default. You can list all available ones using the
configure option <code>--list-demuxers</code>.
</p>
<p>You can disable all the demuxers using the configure option
<code>--disable-demuxers</code>, and selectively enable a single demuxer with
the option <code>--enable-demuxer=<var>DEMUXER</var></code>, or disable it
with the option <code>--disable-demuxer=<var>DEMUXER</var></code>.
</p>
<p>The option <code>-formats</code> of the ff* tools will display the list of
enabled demuxers.
</p>
<p>The description of some of the currently available demuxers follows.
</p>
<a name="applehttp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-applehttp">14.1 applehttp</a></h2>
<p>Apple HTTP Live Streaming demuxer.
</p>
<p>This demuxer presents all AVStreams from all variant streams.
The id field is set to the bitrate variant index number. By setting
the discard flags on AVStreams (by pressing &rsquo;a&rsquo; or &rsquo;v&rsquo; in ffplay),
the caller can decide which variant streams to actually receive.
The total bitrate of the variant that the stream belongs to is
available in a metadata key named &quot;variant_bitrate&quot;.
</p>
<a name="asf"></a>
<h2 class="section"><a href="ffplay-all.html#toc-asf">14.2 asf</a></h2>
<p>Advanced Systems Format demuxer.
</p>
<p>This demuxer is used to demux ASF files and MMS network streams.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>-no_resync_search <var>bool</var></samp>&rsquo;</dt>
<dd><p>Do not try to resynchronize by looking for a certain optional start code.
</p></dd>
</dl>
<p><a name="concat"></a>
</p><a name="concat-2"></a>
<h2 class="section"><a href="ffplay-all.html#toc-concat-2">14.3 concat</a></h2>
<p>Virtual concatenation script demuxer.
</p>
<p>This demuxer reads a list of files and other directives from a text file and
demuxes them one after the other, as if all their packet had been muxed
together.
</p>
<p>The timestamps in the files are adjusted so that the first file starts at 0
and each next file starts where the previous one finishes. Note that it is
done globally and may cause gaps if all streams do not have exactly the same
length.
</p>
<p>All files must have the same streams (same codecs, same time base, etc.).
</p>
<p>The duration of each file is used to adjust the timestamps of the next file:
if the duration is incorrect (because it was computed using the bit-rate or
because the file is truncated, for example), it can cause artifacts. The
<code>duration</code> directive can be used to override the duration stored in
each file.
</p>
<a name="Syntax-1"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Syntax-1">14.3.1 Syntax</a></h3>
<p>The script is a text file in extended-ASCII, with one directive per line.
Empty lines, leading spaces and lines starting with &rsquo;#&rsquo; are ignored. The
following directive is recognized:
</p>
<dl compact="compact">
<dt> &lsquo;<samp><code>file <var>path</var></code></samp>&rsquo;</dt>
<dd><p>Path to a file to read; special characters and spaces must be escaped with
backslash or single quotes.
</p>
<p>All subsequent file-related directives apply to that file.
</p>
</dd>
<dt> &lsquo;<samp><code>ffconcat version 1.0</code></samp>&rsquo;</dt>
<dd><p>Identify the script type and version. It also sets the &lsquo;<samp>safe</samp>&rsquo; option
to 1 if it was to its default -1.
</p>
<p>To make FFmpeg recognize the format automatically, this directive must
appears exactly as is (no extra space or byte-order-mark) on the very first
line of the script.
</p>
</dd>
<dt> &lsquo;<samp><code>duration <var>dur</var></code></samp>&rsquo;</dt>
<dd><p>Duration of the file. This information can be specified from the file;
specifying it here may be more efficient or help if the information from the
file is not available or accurate.
</p>
<p>If the duration is set for all files, then it is possible to seek in the
whole concatenated video.
</p>
</dd>
<dt> &lsquo;<samp><code>stream</code></samp>&rsquo;</dt>
<dd><p>Introduce a stream in the virtual file.
All subsequent stream-related directives apply to the last introduced
stream.
Some streams properties must be set in order to allow identifying the
matching streams in the subfiles.
If no streams are defined in the script, the streams from the first file are
copied.
</p>
</dd>
<dt> &lsquo;<samp><code>exact_stream_id <var>id</var></code></samp>&rsquo;</dt>
<dd><p>Set the id of the stream.
If this directive is given, the string with the corresponding id in the
subfiles will be used.
This is especially useful for MPEG-PS (VOB) files, where the order of the
streams is not reliable.
</p>
</dd>
</dl>
<a name="Options-13"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-13">14.3.2 Options</a></h3>
<p>This demuxer accepts the following option:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>safe</samp>&rsquo;</dt>
<dd><p>If set to 1, reject unsafe file paths. A file path is considered safe if it
does not contain a protocol specification and is relative and all components
only contain characters from the portable character set (letters, digits,
period, underscore and hyphen) and have no period at the beginning of a
component.
</p>
<p>If set to 0, any file name is accepted.
</p>
<p>The default is -1, it is equivalent to 1 if the format was automatically
probed and 0 otherwise.
</p>
</dd>
</dl>
<a name="flv"></a>
<h2 class="section"><a href="ffplay-all.html#toc-flv">14.4 flv</a></h2>
<p>Adobe Flash Video Format demuxer.
</p>
<p>This demuxer is used to demux FLV files and RTMP network streams.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>-flv_metadata <var>bool</var></samp>&rsquo;</dt>
<dd><p>Allocate the streams according to the onMetaData array content.
</p></dd>
</dl>
<a name="libgme"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libgme">14.5 libgme</a></h2>
<p>The Game Music Emu library is a collection of video game music file emulators.
</p>
<p>See <a href="http://code.google.com/p/game-music-emu/">http://code.google.com/p/game-music-emu/</a> for more information.
</p>
<p>Some files have multiple tracks. The demuxer will pick the first track by
default. The &lsquo;<samp>track_index</samp>&rsquo; option can be used to select a different
track. Track indexes start at 0. The demuxer exports the number of tracks as
<var>tracks</var> meta data entry.
</p>
<p>For very large files, the &lsquo;<samp>max_size</samp>&rsquo; option may have to be adjusted.
</p>
<a name="libquvi"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libquvi">14.6 libquvi</a></h2>
<p>Play media from Internet services using the quvi project.
</p>
<p>The demuxer accepts a &lsquo;<samp>format</samp>&rsquo; option to request a specific quality. It
is by default set to <var>best</var>.
</p>
<p>See <a href="http://quvi.sourceforge.net/">http://quvi.sourceforge.net/</a> for more information.
</p>
<p>FFmpeg needs to be built with <code>--enable-libquvi</code> for this demuxer to be
enabled.
</p>
<a name="image2"></a>
<h2 class="section"><a href="ffplay-all.html#toc-image2">14.7 image2</a></h2>
<p>Image file demuxer.
</p>
<p>This demuxer reads from a list of image files specified by a pattern.
The syntax and meaning of the pattern is specified by the
option <var>pattern_type</var>.
</p>
<p>The pattern may contain a suffix which is used to automatically
determine the format of the images contained in the files.
</p>
<p>The size, the pixel format, and the format of each image must be the
same for all the files in the sequence.
</p>
<p>This demuxer accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Set the frame rate for the video stream. It defaults to 25.
</p></dd>
<dt> &lsquo;<samp>loop</samp>&rsquo;</dt>
<dd><p>If set to 1, loop over the input. Default value is 0.
</p></dd>
<dt> &lsquo;<samp>pattern_type</samp>&rsquo;</dt>
<dd><p>Select the pattern type used to interpret the provided filename.
</p>
<p><var>pattern_type</var> accepts one of the following values.
</p><dl compact="compact">
<dt> &lsquo;<samp>sequence</samp>&rsquo;</dt>
<dd><p>Select a sequence pattern type, used to specify a sequence of files
indexed by sequential numbers.
</p>
<p>A sequence pattern may contain the string &quot;%d&quot; or &quot;%0<var>N</var>d&quot;, which
specifies the position of the characters representing a sequential
number in each filename matched by the pattern. If the form
&quot;%d0<var>N</var>d&quot; is used, the string representing the number in each
filename is 0-padded and <var>N</var> is the total number of 0-padded
digits representing the number. The literal character &rsquo;%&rsquo; can be
specified in the pattern with the string &quot;%%&quot;.
</p>
<p>If the sequence pattern contains &quot;%d&quot; or &quot;%0<var>N</var>d&quot;, the first filename of
the file list specified by the pattern must contain a number
inclusively contained between <var>start_number</var> and
<var>start_number</var>+<var>start_number_range</var>-1, and all the following
numbers must be sequential.
</p>
<p>For example the pattern &quot;img-%03d.bmp&quot; will match a sequence of
filenames of the form &lsquo;<tt>img-001.bmp</tt>&rsquo;, &lsquo;<tt>img-002.bmp</tt>&rsquo;, ...,
&lsquo;<tt>img-010.bmp</tt>&rsquo;, etc.; the pattern &quot;i%%m%%g-%d.jpg&quot; will match a
sequence of filenames of the form &lsquo;<tt>i%m%g-1.jpg</tt>&rsquo;,
&lsquo;<tt>i%m%g-2.jpg</tt>&rsquo;, ..., &lsquo;<tt>i%m%g-10.jpg</tt>&rsquo;, etc.
</p>
<p>Note that the pattern must not necessarily contain &quot;%d&quot; or
&quot;%0<var>N</var>d&quot;, for example to convert a single image file
&lsquo;<tt>img.jpeg</tt>&rsquo; you can employ the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i img.jpeg img.png
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>glob</samp>&rsquo;</dt>
<dd><p>Select a glob wildcard pattern type.
</p>
<p>The pattern is interpreted like a <code>glob()</code> pattern. This is only
selectable if libavformat was compiled with globbing support.
</p>
</dd>
<dt> &lsquo;<samp>glob_sequence <em>(deprecated, will be removed)</em></samp>&rsquo;</dt>
<dd><p>Select a mixed glob wildcard/sequence pattern.
</p>
<p>If your version of libavformat was compiled with globbing support, and
the provided pattern contains at least one glob meta character among
<code>%*?[]{}</code> that is preceded by an unescaped &quot;%&quot;, the pattern is
interpreted like a <code>glob()</code> pattern, otherwise it is interpreted
like a sequence pattern.
</p>
<p>All glob special characters <code>%*?[]{}</code> must be prefixed
with &quot;%&quot;. To escape a literal &quot;%&quot; you shall use &quot;%%&quot;.
</p>
<p>For example the pattern <code>foo-%*.jpeg</code> will match all the
filenames prefixed by &quot;foo-&quot; and terminating with &quot;.jpeg&quot;, and
<code>foo-%?%?%?.jpeg</code> will match all the filenames prefixed with
&quot;foo-&quot;, followed by a sequence of three characters, and terminating
with &quot;.jpeg&quot;.
</p>
<p>This pattern type is deprecated in favor of <var>glob</var> and
<var>sequence</var>.
</p></dd>
</dl>
<p>Default value is <var>glob_sequence</var>.
</p></dd>
<dt> &lsquo;<samp>pixel_format</samp>&rsquo;</dt>
<dd><p>Set the pixel format of the images to read. If not specified the pixel
format is guessed from the first image file in the sequence.
</p></dd>
<dt> &lsquo;<samp>start_number</samp>&rsquo;</dt>
<dd><p>Set the index of the file matched by the image file pattern to start
to read from. Default value is 0.
</p></dd>
<dt> &lsquo;<samp>start_number_range</samp>&rsquo;</dt>
<dd><p>Set the index interval range to check when looking for the first image
file in the sequence, starting from <var>start_number</var>. Default value
is 5.
</p></dd>
<dt> &lsquo;<samp>ts_from_file</samp>&rsquo;</dt>
<dd><p>If set to 1, will set frame timestamp to modification time of image file. Note
that monotonity of timestamps is not provided: images go in the same order as
without this option. Default value is 0.
</p></dd>
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Set the video size of the images to read. If not specified the video
size is guessed from the first image file in the sequence.
</p></dd>
</dl>
<a name="Examples-78"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-78">14.7.1 Examples</a></h3>
<ul>
<li>
Use <code>ffmpeg</code> for creating a video from the images in the file
sequence &lsquo;<tt>img-001.jpeg</tt>&rsquo;, &lsquo;<tt>img-002.jpeg</tt>&rsquo;, ..., assuming an
input frame rate of 10 frames per second:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -framerate 10 -i 'img-%03d.jpeg' out.mkv
</pre></td></tr></table>
</li><li>
As above, but start by reading from a file with index 100 in the sequence:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -framerate 10 -start_number 100 -i 'img-%03d.jpeg' out.mkv
</pre></td></tr></table>
</li><li>
Read images matching the &quot;*.png&quot; glob pattern , that is all the files
terminating with the &quot;.png&quot; suffix:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -framerate 10 -pattern_type glob -i &quot;*.png&quot; out.mkv
</pre></td></tr></table>
</li></ul>
<a name="mpegts"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mpegts">14.8 mpegts</a></h2>
<p>MPEG-2 transport stream demuxer.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>fix_teletext_pts</samp>&rsquo;</dt>
<dd><p>Overrides teletext packet PTS and DTS values with the timestamps calculated
from the PCR of the first program which the teletext stream is part of and is
not discarded. Default value is 1, set this option to 0 if you want your
teletext packet PTS and DTS values untouched.
</p></dd>
</dl>
<a name="rawvideo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rawvideo">14.9 rawvideo</a></h2>
<p>Raw video demuxer.
</p>
<p>This demuxer allows one to read raw video data. Since there is no header
specifying the assumed video parameters, the user must specify them
in order to be able to decode the data correctly.
</p>
<p>This demuxer accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Set input video frame rate. Default value is 25.
</p>
</dd>
<dt> &lsquo;<samp>pixel_format</samp>&rsquo;</dt>
<dd><p>Set the input video pixel format. Default value is <code>yuv420p</code>.
</p>
</dd>
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Set the input video size. This value must be specified explicitly.
</p></dd>
</dl>
<p>For example to read a rawvideo file &lsquo;<tt>input.raw</tt>&rsquo; with
<code>ffplay</code>, assuming a pixel format of <code>rgb24</code>, a video
size of <code>320x240</code>, and a frame rate of 10 images per second, use
the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f rawvideo -pixel_format rgb24 -video_size 320x240 -framerate 10 input.raw
</pre></td></tr></table>
<a name="sbg"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sbg">14.10 sbg</a></h2>
<p>SBaGen script demuxer.
</p>
<p>This demuxer reads the script language used by SBaGen
<a href="http://uazu.net/sbagen/">http://uazu.net/sbagen/</a> to generate binaural beats sessions. A SBG
script looks like that:
</p><table><tr><td>&nbsp;</td><td><pre class="example">-SE
a: 300-2.5/3 440+4.5/0
b: 300-2.5/0 440+4.5/3
off: -
NOW == a
+0:07:00 == b
+0:14:00 == a
+0:21:00 == b
+0:30:00 off
</pre></td></tr></table>
<p>A SBG script can mix absolute and relative timestamps. If the script uses
either only absolute timestamps (including the script start time) or only
relative ones, then its layout is fixed, and the conversion is
straightforward. On the other hand, if the script mixes both kind of
timestamps, then the <var>NOW</var> reference for relative timestamps will be
taken from the current time of day at the time the script is read, and the
script layout will be frozen according to that reference. That means that if
the script is directly played, the actual times will match the absolute
timestamps up to the sound controller&rsquo;s clock accuracy, but if the user
somehow pauses the playback or seeks, all times will be shifted accordingly.
</p>
<a name="tedcaptions"></a>
<h2 class="section"><a href="ffplay-all.html#toc-tedcaptions">14.11 tedcaptions</a></h2>
<p>JSON captions used for <a href="http://www.ted.com/">TED Talks</a>.
</p>
<p>TED does not provide links to the captions, but they can be guessed from the
page. The file &lsquo;<tt>tools/bookmarklets.html</tt>&rsquo; from the FFmpeg source tree
contains a bookmarklet to expose them.
</p>
<p>This demuxer accepts the following option:
</p><dl compact="compact">
<dt> &lsquo;<samp>start_time</samp>&rsquo;</dt>
<dd><p>Set the start time of the TED talk, in milliseconds. The default is 15000
(15s). It is used to sync the captions with the downloadable videos, because
they include a 15s intro.
</p></dd>
</dl>
<p>Example: convert the captions to a format most players understand:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i http://www.ted.com/talks/subtitles/id/1/lang/en talk1-en.srt
</pre></td></tr></table>
<a name="Metadata"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Metadata">15. Metadata</a></h1>
<p>FFmpeg is able to dump metadata from media files into a simple UTF-8-encoded
INI-like text file and then load it back using the metadata muxer/demuxer.
</p>
<p>The file format is as follows:
</p><ol>
<li>
A file consists of a header and a number of metadata tags divided into sections,
each on its own line.
</li><li>
The header is a &rsquo;;FFMETADATA&rsquo; string, followed by a version number (now 1).
</li><li>
Metadata tags are of the form &rsquo;key=value&rsquo;
</li><li>
Immediately after header follows global metadata
</li><li>
After global metadata there may be sections with per-stream/per-chapter
metadata.
</li><li>
A section starts with the section name in uppercase (i.e. STREAM or CHAPTER) in
brackets (&rsquo;[&rsquo;, &rsquo;]&rsquo;) and ends with next section or end of file.
</li><li>
At the beginning of a chapter section there may be an optional timebase to be
used for start/end values. It must be in form &rsquo;TIMEBASE=num/den&rsquo;, where num and
den are integers. If the timebase is missing then start/end times are assumed to
be in milliseconds.
Next a chapter section must contain chapter start and end times in form
&rsquo;START=num&rsquo;, &rsquo;END=num&rsquo;, where num is a positive integer.
</li><li>
Empty lines and lines starting with &rsquo;;&rsquo; or &rsquo;#&rsquo; are ignored.
</li><li>
Metadata keys or values containing special characters (&rsquo;=&rsquo;, &rsquo;;&rsquo;, &rsquo;#&rsquo;, &rsquo;\&rsquo; and a
newline) must be escaped with a backslash &rsquo;\&rsquo;.
</li><li>
Note that whitespace in metadata (e.g. foo = bar) is considered to be a part of
the tag (in the example above key is &rsquo;foo &rsquo;, value is &rsquo; bar&rsquo;).
</li></ol>
<p>A ffmetadata file might look like this:
</p><table><tr><td>&nbsp;</td><td><pre class="example">;FFMETADATA1
title=bike\\shed
;this is a comment
artist=FFmpeg troll team
[CHAPTER]
TIMEBASE=1/1000
START=0
#chapter ends at 0:01:00
END=60000
title=chapter \#1
[STREAM]
title=multi\
line
</pre></td></tr></table>
<p>By using the ffmetadata muxer and demuxer it is possible to extract
metadata from an input file to an ffmetadata file, and then transcode
the file into an output file with the edited ffmetadata file.
</p>
<p>Extracting an ffmetadata file with &lsquo;<tt>ffmpeg</tt>&rsquo; goes as follows:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -f ffmetadata FFMETADATAFILE
</pre></td></tr></table>
<p>Reinserting edited metadata information from the FFMETADATAFILE file can
be done as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -i FFMETADATAFILE -map_metadata 1 -codec copy OUTPUT
</pre></td></tr></table>
<a name="Protocols"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Protocols">16. Protocols</a></h1>
<p>Protocols are configured elements in FFmpeg that enable access to
resources that require specific protocols.
</p>
<p>When you configure your FFmpeg build, all the supported protocols are
enabled by default. You can list all available ones using the
configure option &quot;&ndash;list-protocols&quot;.
</p>
<p>You can disable all the protocols using the configure option
&quot;&ndash;disable-protocols&quot;, and selectively enable a protocol using the
option &quot;&ndash;enable-protocol=<var>PROTOCOL</var>&quot;, or you can disable a
particular protocol using the option
&quot;&ndash;disable-protocol=<var>PROTOCOL</var>&quot;.
</p>
<p>The option &quot;-protocols&quot; of the ff* tools will display the list of
supported protocols.
</p>
<p>A description of the currently available protocols follows.
</p>
<a name="bluray"></a>
<h2 class="section"><a href="ffplay-all.html#toc-bluray">16.1 bluray</a></h2>
<p>Read BluRay playlist.
</p>
<p>The accepted options are:
</p><dl compact="compact">
<dt> &lsquo;<samp>angle</samp>&rsquo;</dt>
<dd><p>BluRay angle
</p>
</dd>
<dt> &lsquo;<samp>chapter</samp>&rsquo;</dt>
<dd><p>Start chapter (1...N)
</p>
</dd>
<dt> &lsquo;<samp>playlist</samp>&rsquo;</dt>
<dd><p>Playlist to read (BDMV/PLAYLIST/?????.mpls)
</p>
</dd>
</dl>
<p>Examples:
</p>
<p>Read longest playlist from BluRay mounted to /mnt/bluray:
</p><table><tr><td>&nbsp;</td><td><pre class="example">bluray:/mnt/bluray
</pre></td></tr></table>
<p>Read angle 2 of playlist 4 from BluRay mounted to /mnt/bluray, start from chapter 2:
</p><table><tr><td>&nbsp;</td><td><pre class="example">-playlist 4 -angle 2 -chapter 2 bluray:/mnt/bluray
</pre></td></tr></table>
<a name="cache"></a>
<h2 class="section"><a href="ffplay-all.html#toc-cache">16.2 cache</a></h2>
<p>Caching wrapper for input stream.
</p>
<p>Cache the input stream to temporary file. It brings seeking capability to live streams.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">cache:<var>URL</var>
</pre></td></tr></table>
<a name="concat-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-concat-1">16.3 concat</a></h2>
<p>Physical concatenation protocol.
</p>
<p>Allow to read and seek from many resource in sequence as if they were
a unique resource.
</p>
<p>A URL accepted by this protocol has the syntax:
</p><table><tr><td>&nbsp;</td><td><pre class="example">concat:<var>URL1</var>|<var>URL2</var>|...|<var>URLN</var>
</pre></td></tr></table>
<p>where <var>URL1</var>, <var>URL2</var>, ..., <var>URLN</var> are the urls of the
resource to be concatenated, each one possibly specifying a distinct
protocol.
</p>
<p>For example to read a sequence of files &lsquo;<tt>split1.mpeg</tt>&rsquo;,
&lsquo;<tt>split2.mpeg</tt>&rsquo;, &lsquo;<tt>split3.mpeg</tt>&rsquo; with <code>ffplay</code> use the
command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay concat:split1.mpeg\|split2.mpeg\|split3.mpeg
</pre></td></tr></table>
<p>Note that you may need to escape the character &quot;|&quot; which is special for
many shells.
</p>
<a name="crypto"></a>
<h2 class="section"><a href="ffplay-all.html#toc-crypto">16.4 crypto</a></h2>
<p>AES-encrypted stream reading protocol.
</p>
<p>The accepted options are:
</p><dl compact="compact">
<dt> &lsquo;<samp>key</samp>&rsquo;</dt>
<dd><p>Set the AES decryption key binary block from given hexadecimal representation.
</p>
</dd>
<dt> &lsquo;<samp>iv</samp>&rsquo;</dt>
<dd><p>Set the AES decryption initialization vector binary block from given hexadecimal representation.
</p></dd>
</dl>
<p>Accepted URL formats:
</p><table><tr><td>&nbsp;</td><td><pre class="example">crypto:<var>URL</var>
crypto+<var>URL</var>
</pre></td></tr></table>
<a name="data"></a>
<h2 class="section"><a href="ffplay-all.html#toc-data">16.5 data</a></h2>
<p>Data in-line in the URI. See <a href="http://en.wikipedia.org/wiki/Data_URI_scheme">http://en.wikipedia.org/wiki/Data_URI_scheme</a>.
</p>
<p>For example, to convert a GIF file given inline with <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i &quot;data:image/gif;base64,R0lGODdhCAAIAMIEAAAAAAAA//8AAP//AP///////////////ywAAAAACAAIAAADF0gEDLojDgdGiJdJqUX02iB4E8Q9jUMkADs=&quot; smiley.png
</pre></td></tr></table>
<a name="file"></a>
<h2 class="section"><a href="ffplay-all.html#toc-file">16.6 file</a></h2>
<p>File access protocol.
</p>
<p>Allow to read from or write to a file.
</p>
<p>A file URL can have the form:
</p><table><tr><td>&nbsp;</td><td><pre class="example">file:<var>filename</var>
</pre></td></tr></table>
<p>where <var>filename</var> is the path of the file to read.
</p>
<p>An URL that does not have a protocol prefix will be assumed to be a
file URL. Depending on the build, an URL that looks like a Windows
path with the drive letter at the beginning will also be assumed to be
a file URL (usually not the case in builds for unix-like systems).
</p>
<p>For example to read from a file &lsquo;<tt>input.mpeg</tt>&rsquo; with <code>ffmpeg</code>
use the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i file:input.mpeg output.mpeg
</pre></td></tr></table>
<p>This protocol accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>truncate</samp>&rsquo;</dt>
<dd><p>Truncate existing files on write, if set to 1. A value of 0 prevents
truncating. Default value is 1.
</p>
</dd>
<dt> &lsquo;<samp>blocksize</samp>&rsquo;</dt>
<dd><p>Set I/O operation maximum block size, in bytes. Default value is
<code>INT_MAX</code>, which results in not limiting the requested block size.
Setting this value reasonably low improves user termination request reaction
time, which is valuable for files on slow medium.
</p></dd>
</dl>
<a name="ftp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ftp">16.7 ftp</a></h2>
<p>FTP (File Transfer Protocol).
</p>
<p>Allow to read from or write to remote resources using FTP protocol.
</p>
<p>Following syntax is required.
</p><table><tr><td>&nbsp;</td><td><pre class="example">ftp://[user[:password]@]server[:port]/path/to/remote/resource.mpeg
</pre></td></tr></table>
<p>This protocol accepts the following options.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Set timeout of socket I/O operations used by the underlying low level
operation. By default it is set to -1, which means that the timeout is
not specified.
</p>
</dd>
<dt> &lsquo;<samp>ftp-anonymous-password</samp>&rsquo;</dt>
<dd><p>Password used when login as anonymous user. Typically an e-mail address
should be used.
</p>
</dd>
<dt> &lsquo;<samp>ftp-write-seekable</samp>&rsquo;</dt>
<dd><p>Control seekability of connection during encoding. If set to 1 the
resource is supposed to be seekable, if set to 0 it is assumed not
to be seekable. Default value is 0.
</p></dd>
</dl>
<p>NOTE: Protocol can be used as output, but it is recommended to not do
it, unless special care is taken (tests, customized server configuration
etc.). Different FTP servers behave in different way during seek
operation. ff* tools may produce incomplete content due to server limitations.
</p>
<a name="gopher"></a>
<h2 class="section"><a href="ffplay-all.html#toc-gopher">16.8 gopher</a></h2>
<p>Gopher protocol.
</p>
<a name="hls"></a>
<h2 class="section"><a href="ffplay-all.html#toc-hls">16.9 hls</a></h2>
<p>Read Apple HTTP Live Streaming compliant segmented stream as
a uniform one. The M3U8 playlists describing the segments can be
remote HTTP resources or local files, accessed using the standard
file protocol.
The nested protocol is declared by specifying
&quot;+<var>proto</var>&quot; after the hls URI scheme name, where <var>proto</var>
is either &quot;file&quot; or &quot;http&quot;.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">hls+http://host/path/to/remote/resource.m3u8
hls+file://path/to/local/resource.m3u8
</pre></td></tr></table>
<p>Using this protocol is discouraged - the hls demuxer should work
just as well (if not, please report the issues) and is more complete.
To use the hls demuxer instead, simply use the direct URLs to the
m3u8 files.
</p>
<a name="http"></a>
<h2 class="section"><a href="ffplay-all.html#toc-http">16.10 http</a></h2>
<p>HTTP (Hyper Text Transfer Protocol).
</p>
<p>This protocol accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>seekable</samp>&rsquo;</dt>
<dd><p>Control seekability of connection. If set to 1 the resource is
supposed to be seekable, if set to 0 it is assumed not to be seekable,
if set to -1 it will try to autodetect if it is seekable. Default
value is -1.
</p>
</dd>
<dt> &lsquo;<samp>chunked_post</samp>&rsquo;</dt>
<dd><p>If set to 1 use chunked Transfer-Encoding for posts, default is 1.
</p>
</dd>
<dt> &lsquo;<samp>content_type</samp>&rsquo;</dt>
<dd><p>Set a specific content type for the POST messages.
</p>
</dd>
<dt> &lsquo;<samp>headers</samp>&rsquo;</dt>
<dd><p>Set custom HTTP headers, can override built in default headers. The
value must be a string encoding the headers.
</p>
</dd>
<dt> &lsquo;<samp>multiple_requests</samp>&rsquo;</dt>
<dd><p>Use persistent connections if set to 1, default is 0.
</p>
</dd>
<dt> &lsquo;<samp>post_data</samp>&rsquo;</dt>
<dd><p>Set custom HTTP post data.
</p>
</dd>
<dt> &lsquo;<samp>user-agent</samp>&rsquo;</dt>
<dt> &lsquo;<samp>user_agent</samp>&rsquo;</dt>
<dd><p>Override the User-Agent header. If not specified the protocol will use a
string describing the libavformat build. (&quot;Lavf/&lt;version&gt;&quot;)
</p>
</dd>
<dt> &lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Set timeout of socket I/O operations used by the underlying low level
operation. By default it is set to -1, which means that the timeout is
not specified.
</p>
</dd>
<dt> &lsquo;<samp>mime_type</samp>&rsquo;</dt>
<dd><p>Export the MIME type.
</p>
</dd>
<dt> &lsquo;<samp>icy</samp>&rsquo;</dt>
<dd><p>If set to 1 request ICY (SHOUTcast) metadata from the server. If the server
supports this, the metadata has to be retrieved by the application by reading
the &lsquo;<samp>icy_metadata_headers</samp>&rsquo; and &lsquo;<samp>icy_metadata_packet</samp>&rsquo; options.
The default is 0.
</p>
</dd>
<dt> &lsquo;<samp>icy_metadata_headers</samp>&rsquo;</dt>
<dd><p>If the server supports ICY metadata, this contains the ICY-specific HTTP reply
headers, separated by newline characters.
</p>
</dd>
<dt> &lsquo;<samp>icy_metadata_packet</samp>&rsquo;</dt>
<dd><p>If the server supports ICY metadata, and &lsquo;<samp>icy</samp>&rsquo; was set to 1, this
contains the last non-empty metadata packet sent by the server. It should be
polled in regular intervals by applications interested in mid-stream metadata
updates.
</p>
</dd>
<dt> &lsquo;<samp>cookies</samp>&rsquo;</dt>
<dd><p>Set the cookies to be sent in future requests. The format of each cookie is the
same as the value of a Set-Cookie HTTP response field. Multiple cookies can be
delimited by a newline character.
</p>
</dd>
<dt> &lsquo;<samp>offset</samp>&rsquo;</dt>
<dd><p>Set initial byte offset.
</p>
</dd>
<dt> &lsquo;<samp>end_offset</samp>&rsquo;</dt>
<dd><p>Try to limit the request to bytes preceding this offset.
</p></dd>
</dl>
<a name="HTTP-Cookies"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-HTTP-Cookies">16.10.1 HTTP Cookies</a></h3>
<p>Some HTTP requests will be denied unless cookie values are passed in with the
request. The &lsquo;<samp>cookies</samp>&rsquo; option allows these cookies to be specified. At
the very least, each cookie must specify a value along with a path and domain.
HTTP requests that match both the domain and path will automatically include the
cookie value in the HTTP Cookie header field. Multiple cookies can be delimited
by a newline.
</p>
<p>The required syntax to play a stream specifying a cookie is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay -cookies &quot;nlqptid=nltid=tsn; path=/; domain=somedomain.com;&quot; http://somedomain.com/somestream.m3u8
</pre></td></tr></table>
<a name="mmst"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mmst">16.11 mmst</a></h2>
<p>MMS (Microsoft Media Server) protocol over TCP.
</p>
<a name="mmsh"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mmsh">16.12 mmsh</a></h2>
<p>MMS (Microsoft Media Server) protocol over HTTP.
</p>
<p>The required syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">mmsh://<var>server</var>[:<var>port</var>][/<var>app</var>][/<var>playpath</var>]
</pre></td></tr></table>
<a name="md5"></a>
<h2 class="section"><a href="ffplay-all.html#toc-md5">16.13 md5</a></h2>
<p>MD5 output protocol.
</p>
<p>Computes the MD5 hash of the data to be written, and on close writes
this to the designated output or stdout if none is specified. It can
be used to test muxers without writing an actual file.
</p>
<p>Some examples follow.
</p><table><tr><td>&nbsp;</td><td><pre class="example"># Write the MD5 hash of the encoded AVI file to the file output.avi.md5.
ffmpeg -i input.flv -f avi -y md5:output.avi.md5
# Write the MD5 hash of the encoded AVI file to stdout.
ffmpeg -i input.flv -f avi -y md5:
</pre></td></tr></table>
<p>Note that some formats (typically MOV) require the output protocol to
be seekable, so they will fail with the MD5 output protocol.
</p>
<a name="pipe"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pipe">16.14 pipe</a></h2>
<p>UNIX pipe access protocol.
</p>
<p>Allow to read and write from UNIX pipes.
</p>
<p>The accepted syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pipe:[<var>number</var>]
</pre></td></tr></table>
<p><var>number</var> is the number corresponding to the file descriptor of the
pipe (e.g. 0 for stdin, 1 for stdout, 2 for stderr). If <var>number</var>
is not specified, by default the stdout file descriptor will be used
for writing, stdin for reading.
</p>
<p>For example to read from stdin with <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">cat test.wav | ffmpeg -i pipe:0
# ...this is the same as...
cat test.wav | ffmpeg -i pipe:
</pre></td></tr></table>
<p>For writing to stdout with <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i test.wav -f avi pipe:1 | cat &gt; test.avi
# ...this is the same as...
ffmpeg -i test.wav -f avi pipe: | cat &gt; test.avi
</pre></td></tr></table>
<p>This protocol accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>blocksize</samp>&rsquo;</dt>
<dd><p>Set I/O operation maximum block size, in bytes. Default value is
<code>INT_MAX</code>, which results in not limiting the requested block size.
Setting this value reasonably low improves user termination request reaction
time, which is valuable if data transmission is slow.
</p></dd>
</dl>
<p>Note that some formats (typically MOV), require the output protocol to
be seekable, so they will fail with the pipe output protocol.
</p>
<a name="rtmp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtmp">16.15 rtmp</a></h2>
<p>Real-Time Messaging Protocol.
</p>
<p>The Real-Time Messaging Protocol (RTMP) is used for streaming multimedia
content across a TCP/IP network.
</p>
<p>The required syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">rtmp://[<var>username</var>:<var>password</var>@]<var>server</var>[:<var>port</var>][/<var>app</var>][/<var>instance</var>][/<var>playpath</var>]
</pre></td></tr></table>
<p>The accepted parameters are:
</p><dl compact="compact">
<dt> &lsquo;<samp>username</samp>&rsquo;</dt>
<dd><p>An optional username (mostly for publishing).
</p>
</dd>
<dt> &lsquo;<samp>password</samp>&rsquo;</dt>
<dd><p>An optional password (mostly for publishing).
</p>
</dd>
<dt> &lsquo;<samp>server</samp>&rsquo;</dt>
<dd><p>The address of the RTMP server.
</p>
</dd>
<dt> &lsquo;<samp>port</samp>&rsquo;</dt>
<dd><p>The number of the TCP port to use (by default is 1935).
</p>
</dd>
<dt> &lsquo;<samp>app</samp>&rsquo;</dt>
<dd><p>It is the name of the application to access. It usually corresponds to
the path where the application is installed on the RTMP server
(e.g. &lsquo;<tt>/ondemand/</tt>&rsquo;, &lsquo;<tt>/flash/live/</tt>&rsquo;, etc.). You can override
the value parsed from the URI through the <code>rtmp_app</code> option, too.
</p>
</dd>
<dt> &lsquo;<samp>playpath</samp>&rsquo;</dt>
<dd><p>It is the path or name of the resource to play with reference to the
application specified in <var>app</var>, may be prefixed by &quot;mp4:&quot;. You
can override the value parsed from the URI through the <code>rtmp_playpath</code>
option, too.
</p>
</dd>
<dt> &lsquo;<samp>listen</samp>&rsquo;</dt>
<dd><p>Act as a server, listening for an incoming connection.
</p>
</dd>
<dt> &lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Maximum time to wait for the incoming connection. Implies listen.
</p></dd>
</dl>
<p>Additionally, the following parameters can be set via command line options
(or in code via <code>AVOption</code>s):
</p><dl compact="compact">
<dt> &lsquo;<samp>rtmp_app</samp>&rsquo;</dt>
<dd><p>Name of application to connect on the RTMP server. This option
overrides the parameter specified in the URI.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_buffer</samp>&rsquo;</dt>
<dd><p>Set the client buffer time in milliseconds. The default is 3000.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_conn</samp>&rsquo;</dt>
<dd><p>Extra arbitrary AMF connection parameters, parsed from a string,
e.g. like <code>B:1 S:authMe O:1 NN:code:1.23 NS:flag:ok O:0</code>.
Each value is prefixed by a single character denoting the type,
B for Boolean, N for number, S for string, O for object, or Z for null,
followed by a colon. For Booleans the data must be either 0 or 1 for
FALSE or TRUE, respectively. Likewise for Objects the data must be 0 or
1 to end or begin an object, respectively. Data items in subobjects may
be named, by prefixing the type with &rsquo;N&rsquo; and specifying the name before
the value (i.e. <code>NB:myFlag:1</code>). This option may be used multiple
times to construct arbitrary AMF sequences.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_flashver</samp>&rsquo;</dt>
<dd><p>Version of the Flash plugin used to run the SWF player. The default
is LNX 9,0,124,2. (When publishing, the default is FMLE/3.0 (compatible;
&lt;libavformat version&gt;).)
</p>
</dd>
<dt> &lsquo;<samp>rtmp_flush_interval</samp>&rsquo;</dt>
<dd><p>Number of packets flushed in the same request (RTMPT only). The default
is 10.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_live</samp>&rsquo;</dt>
<dd><p>Specify that the media is a live stream. No resuming or seeking in
live streams is possible. The default value is <code>any</code>, which means the
subscriber first tries to play the live stream specified in the
playpath. If a live stream of that name is not found, it plays the
recorded stream. The other possible values are <code>live</code> and
<code>recorded</code>.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_pageurl</samp>&rsquo;</dt>
<dd><p>URL of the web page in which the media was embedded. By default no
value will be sent.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_playpath</samp>&rsquo;</dt>
<dd><p>Stream identifier to play or to publish. This option overrides the
parameter specified in the URI.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_subscribe</samp>&rsquo;</dt>
<dd><p>Name of live stream to subscribe to. By default no value will be sent.
It is only sent if the option is specified or if rtmp_live
is set to live.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_swfhash</samp>&rsquo;</dt>
<dd><p>SHA256 hash of the decompressed SWF file (32 bytes).
</p>
</dd>
<dt> &lsquo;<samp>rtmp_swfsize</samp>&rsquo;</dt>
<dd><p>Size of the decompressed SWF file, required for SWFVerification.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_swfurl</samp>&rsquo;</dt>
<dd><p>URL of the SWF player for the media. By default no value will be sent.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_swfverify</samp>&rsquo;</dt>
<dd><p>URL to player swf file, compute hash/size automatically.
</p>
</dd>
<dt> &lsquo;<samp>rtmp_tcurl</samp>&rsquo;</dt>
<dd><p>URL of the target stream. Defaults to proto://host[:port]/app.
</p>
</dd>
</dl>
<p>For example to read with <code>ffplay</code> a multimedia resource named
&quot;sample&quot; from the application &quot;vod&quot; from an RTMP server &quot;myserver&quot;:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay rtmp://myserver/vod/sample
</pre></td></tr></table>
<p>To publish to a password protected server, passing the playpath and
app names separately:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -re -i &lt;input&gt; -f flv -rtmp_playpath some/long/path -rtmp_app long/app/name rtmp://username:password@myserver/
</pre></td></tr></table>
<a name="rtmpe"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtmpe">16.16 rtmpe</a></h2>
<p>Encrypted Real-Time Messaging Protocol.
</p>
<p>The Encrypted Real-Time Messaging Protocol (RTMPE) is used for
streaming multimedia content within standard cryptographic primitives,
consisting of Diffie-Hellman key exchange and HMACSHA256, generating
a pair of RC4 keys.
</p>
<a name="rtmps"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtmps">16.17 rtmps</a></h2>
<p>Real-Time Messaging Protocol over a secure SSL connection.
</p>
<p>The Real-Time Messaging Protocol (RTMPS) is used for streaming
multimedia content across an encrypted connection.
</p>
<a name="rtmpt"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtmpt">16.18 rtmpt</a></h2>
<p>Real-Time Messaging Protocol tunneled through HTTP.
</p>
<p>The Real-Time Messaging Protocol tunneled through HTTP (RTMPT) is used
for streaming multimedia content within HTTP requests to traverse
firewalls.
</p>
<a name="rtmpte"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtmpte">16.19 rtmpte</a></h2>
<p>Encrypted Real-Time Messaging Protocol tunneled through HTTP.
</p>
<p>The Encrypted Real-Time Messaging Protocol tunneled through HTTP (RTMPTE)
is used for streaming multimedia content within HTTP requests to traverse
firewalls.
</p>
<a name="rtmpts"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtmpts">16.20 rtmpts</a></h2>
<p>Real-Time Messaging Protocol tunneled through HTTPS.
</p>
<p>The Real-Time Messaging Protocol tunneled through HTTPS (RTMPTS) is used
for streaming multimedia content within HTTPS requests to traverse
firewalls.
</p>
<a name="libssh"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libssh">16.21 libssh</a></h2>
<p>Secure File Transfer Protocol via libssh
</p>
<p>Allow to read from or write to remote resources using SFTP protocol.
</p>
<p>Following syntax is required.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">sftp://[user[:password]@]server[:port]/path/to/remote/resource.mpeg
</pre></td></tr></table>
<p>This protocol accepts the following options.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Set timeout of socket I/O operations used by the underlying low level
operation. By default it is set to -1, which means that the timeout
is not specified.
</p>
</dd>
<dt> &lsquo;<samp>truncate</samp>&rsquo;</dt>
<dd><p>Truncate existing files on write, if set to 1. A value of 0 prevents
truncating. Default value is 1.
</p>
</dd>
<dt> &lsquo;<samp>private_key</samp>&rsquo;</dt>
<dd><p>Specify the path of the file containing private key to use during authorization.
By default libssh searches for keys in the &lsquo;<tt>~/.ssh/</tt>&rsquo; directory.
</p>
</dd>
</dl>
<p>Example: Play a file stored on remote server.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay sftp://user:password@server_address:22/home/user/resource.mpeg
</pre></td></tr></table>
<a name="librtmp-rtmp_002c-rtmpe_002c-rtmps_002c-rtmpt_002c-rtmpte"></a>
<h2 class="section"><a href="ffplay-all.html#toc-librtmp-rtmp_002c-rtmpe_002c-rtmps_002c-rtmpt_002c-rtmpte">16.22 librtmp rtmp, rtmpe, rtmps, rtmpt, rtmpte</a></h2>
<p>Real-Time Messaging Protocol and its variants supported through
librtmp.
</p>
<p>Requires the presence of the librtmp headers and library during
configuration. You need to explicitly configure the build with
&quot;&ndash;enable-librtmp&quot;. If enabled this will replace the native RTMP
protocol.
</p>
<p>This protocol provides most client functions and a few server
functions needed to support RTMP, RTMP tunneled in HTTP (RTMPT),
encrypted RTMP (RTMPE), RTMP over SSL/TLS (RTMPS) and tunneled
variants of these encrypted types (RTMPTE, RTMPTS).
</p>
<p>The required syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>rtmp_proto</var>://<var>server</var>[:<var>port</var>][/<var>app</var>][/<var>playpath</var>] <var>options</var>
</pre></td></tr></table>
<p>where <var>rtmp_proto</var> is one of the strings &quot;rtmp&quot;, &quot;rtmpt&quot;, &quot;rtmpe&quot;,
&quot;rtmps&quot;, &quot;rtmpte&quot;, &quot;rtmpts&quot; corresponding to each RTMP variant, and
<var>server</var>, <var>port</var>, <var>app</var> and <var>playpath</var> have the same
meaning as specified for the RTMP native protocol.
<var>options</var> contains a list of space-separated options of the form
<var>key</var>=<var>val</var>.
</p>
<p>See the librtmp manual page (man 3 librtmp) for more information.
</p>
<p>For example, to stream a file in real-time to an RTMP server using
<code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -re -i myfile -f flv rtmp://myserver/live/mystream
</pre></td></tr></table>
<p>To play the same stream using <code>ffplay</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay &quot;rtmp://myserver/live/mystream live=1&quot;
</pre></td></tr></table>
<a name="rtp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtp">16.23 rtp</a></h2>
<p>Real-time Transport Protocol.
</p>
<p>The required syntax for an RTP URL is:
rtp://<var>hostname</var>[:<var>port</var>][?<var>option</var>=<var>val</var>...]
</p>
<p><var>port</var> specifies the RTP port to use.
</p>
<p>The following URL options are supported:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>ttl=<var>n</var></samp>&rsquo;</dt>
<dd><p>Set the TTL (Time-To-Live) value (for multicast only).
</p>
</dd>
<dt> &lsquo;<samp>rtcpport=<var>n</var></samp>&rsquo;</dt>
<dd><p>Set the remote RTCP port to <var>n</var>.
</p>
</dd>
<dt> &lsquo;<samp>localrtpport=<var>n</var></samp>&rsquo;</dt>
<dd><p>Set the local RTP port to <var>n</var>.
</p>
</dd>
<dt> &lsquo;<samp>localrtcpport=<var>n</var>'</samp>&rsquo;</dt>
<dd><p>Set the local RTCP port to <var>n</var>.
</p>
</dd>
<dt> &lsquo;<samp>pkt_size=<var>n</var></samp>&rsquo;</dt>
<dd><p>Set max packet size (in bytes) to <var>n</var>.
</p>
</dd>
<dt> &lsquo;<samp>connect=0|1</samp>&rsquo;</dt>
<dd><p>Do a <code>connect()</code> on the UDP socket (if set to 1) or not (if set
to 0).
</p>
</dd>
<dt> &lsquo;<samp>sources=<var>ip</var>[,<var>ip</var>]</samp>&rsquo;</dt>
<dd><p>List allowed source IP addresses.
</p>
</dd>
<dt> &lsquo;<samp>block=<var>ip</var>[,<var>ip</var>]</samp>&rsquo;</dt>
<dd><p>List disallowed (blocked) source IP addresses.
</p>
</dd>
<dt> &lsquo;<samp>write_to_source=0|1</samp>&rsquo;</dt>
<dd><p>Send packets to the source address of the latest received packet (if
set to 1) or to a default remote address (if set to 0).
</p>
</dd>
<dt> &lsquo;<samp>localport=<var>n</var></samp>&rsquo;</dt>
<dd><p>Set the local RTP port to <var>n</var>.
</p>
<p>This is a deprecated option. Instead, &lsquo;<samp>localrtpport</samp>&rsquo; should be
used.
</p>
</dd>
</dl>
<p>Important notes:
</p>
<ol>
<li>
If &lsquo;<samp>rtcpport</samp>&rsquo; is not set the RTCP port will be set to the RTP
port value plus 1.
</li><li>
If &lsquo;<samp>localrtpport</samp>&rsquo; (the local RTP port) is not set any available
port will be used for the local RTP and RTCP ports.
</li><li>
If &lsquo;<samp>localrtcpport</samp>&rsquo; (the local RTCP port) is not set it will be
set to the the local RTP port value plus 1.
</li></ol>
<a name="rtsp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rtsp">16.24 rtsp</a></h2>
<p>Real-Time Streaming Protocol.
</p>
<p>RTSP is not technically a protocol handler in libavformat, it is a demuxer
and muxer. The demuxer supports both normal RTSP (with data transferred
over RTP; this is used by e.g. Apple and Microsoft) and Real-RTSP (with
data transferred over RDT).
</p>
<p>The muxer can be used to send a stream using RTSP ANNOUNCE to a server
supporting it (currently Darwin Streaming Server and Mischa Spiegelmock&rsquo;s
<a href="https://github.com/revmischa/rtsp-server">RTSP server</a>).
</p>
<p>The required syntax for a RTSP url is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">rtsp://<var>hostname</var>[:<var>port</var>]/<var>path</var>
</pre></td></tr></table>
<p>Options can be set on the <code>ffmpeg</code>/<code>ffplay</code> command
line, or set in code via <code>AVOption</code>s or in
<code>avformat_open_input</code>.
</p>
<p>The following options are supported.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>initial_pause</samp>&rsquo;</dt>
<dd><p>Do not start playing the stream immediately if set to 1. Default value
is 0.
</p>
</dd>
<dt> &lsquo;<samp>rtsp_transport</samp>&rsquo;</dt>
<dd><p>Set RTSP trasport protocols.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>udp</samp>&rsquo;</dt>
<dd><p>Use UDP as lower transport protocol.
</p>
</dd>
<dt> &lsquo;<samp>tcp</samp>&rsquo;</dt>
<dd><p>Use TCP (interleaving within the RTSP control channel) as lower
transport protocol.
</p>
</dd>
<dt> &lsquo;<samp>udp_multicast</samp>&rsquo;</dt>
<dd><p>Use UDP multicast as lower transport protocol.
</p>
</dd>
<dt> &lsquo;<samp>http</samp>&rsquo;</dt>
<dd><p>Use HTTP tunneling as lower transport protocol, which is useful for
passing proxies.
</p></dd>
</dl>
<p>Multiple lower transport protocols may be specified, in that case they are
tried one at a time (if the setup of one fails, the next one is tried).
For the muxer, only the &lsquo;<samp>tcp</samp>&rsquo; and &lsquo;<samp>udp</samp>&rsquo; options are supported.
</p>
</dd>
<dt> &lsquo;<samp>rtsp_flags</samp>&rsquo;</dt>
<dd><p>Set RTSP flags.
</p>
<p>The following values are accepted:
</p><dl compact="compact">
<dt> &lsquo;<samp>filter_src</samp>&rsquo;</dt>
<dd><p>Accept packets only from negotiated peer address and port.
</p></dd>
<dt> &lsquo;<samp>listen</samp>&rsquo;</dt>
<dd><p>Act as a server, listening for an incoming connection.
</p></dd>
<dt> &lsquo;<samp>prefer_tcp</samp>&rsquo;</dt>
<dd><p>Try TCP for RTP transport first, if TCP is available as RTSP RTP transport.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>none</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>allowed_media_types</samp>&rsquo;</dt>
<dd><p>Set media types to accept from the server.
</p>
<p>The following flags are accepted:
</p><dl compact="compact">
<dt> &lsquo;<samp>video</samp>&rsquo;</dt>
<dt> &lsquo;<samp>audio</samp>&rsquo;</dt>
<dt> &lsquo;<samp>data</samp>&rsquo;</dt>
</dl>
<p>By default it accepts all media types.
</p>
</dd>
<dt> &lsquo;<samp>min_port</samp>&rsquo;</dt>
<dd><p>Set minimum local UDP port. Default value is 5000.
</p>
</dd>
<dt> &lsquo;<samp>max_port</samp>&rsquo;</dt>
<dd><p>Set maximum local UDP port. Default value is 65000.
</p>
</dd>
<dt> &lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Set maximum timeout (in seconds) to wait for incoming connections.
</p>
<p>A value of -1 mean infinite (default). This option implies the
&lsquo;<samp>rtsp_flags</samp>&rsquo; set to &lsquo;<samp>listen</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>reorder_queue_size</samp>&rsquo;</dt>
<dd><p>Set number of packets to buffer for handling of reordered packets.
</p>
</dd>
<dt> &lsquo;<samp>stimeout</samp>&rsquo;</dt>
<dd><p>Set socket TCP I/O timeout in micro seconds.
</p>
</dd>
<dt> &lsquo;<samp>user-agent</samp>&rsquo;</dt>
<dd><p>Override User-Agent header. If not specified, it default to the
libavformat identifier string.
</p></dd>
</dl>
<p>When receiving data over UDP, the demuxer tries to reorder received packets
(since they may arrive out of order, or packets may get lost totally). This
can be disabled by setting the maximum demuxing delay to zero (via
the <code>max_delay</code> field of AVFormatContext).
</p>
<p>When watching multi-bitrate Real-RTSP streams with <code>ffplay</code>, the
streams to display can be chosen with <code>-vst</code> <var>n</var> and
<code>-ast</code> <var>n</var> for video and audio respectively, and can be switched
on the fly by pressing <code>v</code> and <code>a</code>.
</p>
<a name="Examples-4"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-4">16.24.1 Examples</a></h3>
<p>The following examples all make use of the <code>ffplay</code> and
<code>ffmpeg</code> tools.
</p>
<ul>
<li>
Watch a stream over UDP, with a max reordering delay of 0.5 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -max_delay 500000 -rtsp_transport udp rtsp://server/video.mp4
</pre></td></tr></table>
</li><li>
Watch a stream tunneled over HTTP:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -rtsp_transport http rtsp://server/video.mp4
</pre></td></tr></table>
</li><li>
Send a stream in realtime to a RTSP server, for others to watch:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -re -i <var>input</var> -f rtsp -muxdelay 0.1 rtsp://server/live.sdp
</pre></td></tr></table>
</li><li>
Receive a stream in realtime:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -rtsp_flags listen -i rtsp://ownaddress/live.sdp <var>output</var>
</pre></td></tr></table>
</li></ul>
<a name="sap"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sap">16.25 sap</a></h2>
<p>Session Announcement Protocol (RFC 2974). This is not technically a
protocol handler in libavformat, it is a muxer and demuxer.
It is used for signalling of RTP streams, by announcing the SDP for the
streams regularly on a separate port.
</p>
<a name="Muxer"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Muxer">16.25.1 Muxer</a></h3>
<p>The syntax for a SAP url given to the muxer is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">sap://<var>destination</var>[:<var>port</var>][?<var>options</var>]
</pre></td></tr></table>
<p>The RTP packets are sent to <var>destination</var> on port <var>port</var>,
or to port 5004 if no port is specified.
<var>options</var> is a <code>&amp;</code>-separated list. The following options
are supported:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>announce_addr=<var>address</var></samp>&rsquo;</dt>
<dd><p>Specify the destination IP address for sending the announcements to.
If omitted, the announcements are sent to the commonly used SAP
announcement multicast address 224.2.127.254 (sap.mcast.net), or
ff0e::2:7ffe if <var>destination</var> is an IPv6 address.
</p>
</dd>
<dt> &lsquo;<samp>announce_port=<var>port</var></samp>&rsquo;</dt>
<dd><p>Specify the port to send the announcements on, defaults to
9875 if not specified.
</p>
</dd>
<dt> &lsquo;<samp>ttl=<var>ttl</var></samp>&rsquo;</dt>
<dd><p>Specify the time to live value for the announcements and RTP packets,
defaults to 255.
</p>
</dd>
<dt> &lsquo;<samp>same_port=<var>0|1</var></samp>&rsquo;</dt>
<dd><p>If set to 1, send all RTP streams on the same port pair. If zero (the
default), all streams are sent on unique ports, with each stream on a
port 2 numbers higher than the previous.
VLC/Live555 requires this to be set to 1, to be able to receive the stream.
The RTP stack in libavformat for receiving requires all streams to be sent
on unique ports.
</p></dd>
</dl>
<p>Example command lines follow.
</p>
<p>To broadcast a stream on the local subnet, for watching in VLC:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -re -i <var>input</var> -f sap sap://224.0.0.255?same_port=1
</pre></td></tr></table>
<p>Similarly, for watching in <code>ffplay</code>:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -re -i <var>input</var> -f sap sap://224.0.0.255
</pre></td></tr></table>
<p>And for watching in <code>ffplay</code>, over IPv6:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -re -i <var>input</var> -f sap sap://[ff0e::1:2:3:4]
</pre></td></tr></table>
<a name="Demuxer"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Demuxer">16.25.2 Demuxer</a></h3>
<p>The syntax for a SAP url given to the demuxer is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">sap://[<var>address</var>][:<var>port</var>]
</pre></td></tr></table>
<p><var>address</var> is the multicast address to listen for announcements on,
if omitted, the default 224.2.127.254 (sap.mcast.net) is used. <var>port</var>
is the port that is listened on, 9875 if omitted.
</p>
<p>The demuxers listens for announcements on the given address and port.
Once an announcement is received, it tries to receive that particular stream.
</p>
<p>Example command lines follow.
</p>
<p>To play back the first stream announced on the normal SAP multicast address:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay sap://
</pre></td></tr></table>
<p>To play back the first stream announced on one the default IPv6 SAP multicast address:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay sap://[ff0e::2:7ffe]
</pre></td></tr></table>
<a name="sctp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sctp">16.26 sctp</a></h2>
<p>Stream Control Transmission Protocol.
</p>
<p>The accepted URL syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">sctp://<var>host</var>:<var>port</var>[?<var>options</var>]
</pre></td></tr></table>
<p>The protocol accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>listen</samp>&rsquo;</dt>
<dd><p>If set to any value, listen for an incoming connection. Outgoing connection is done by default.
</p>
</dd>
<dt> &lsquo;<samp>max_streams</samp>&rsquo;</dt>
<dd><p>Set the maximum number of streams. By default no limit is set.
</p></dd>
</dl>
<a name="srtp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-srtp">16.27 srtp</a></h2>
<p>Secure Real-time Transport Protocol.
</p>
<p>The accepted options are:
</p><dl compact="compact">
<dt> &lsquo;<samp>srtp_in_suite</samp>&rsquo;</dt>
<dt> &lsquo;<samp>srtp_out_suite</samp>&rsquo;</dt>
<dd><p>Select input and output encoding suites.
</p>
<p>Supported values:
</p><dl compact="compact">
<dt> &lsquo;<samp>AES_CM_128_HMAC_SHA1_80</samp>&rsquo;</dt>
<dt> &lsquo;<samp>SRTP_AES128_CM_HMAC_SHA1_80</samp>&rsquo;</dt>
<dt> &lsquo;<samp>AES_CM_128_HMAC_SHA1_32</samp>&rsquo;</dt>
<dt> &lsquo;<samp>SRTP_AES128_CM_HMAC_SHA1_32</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>srtp_in_params</samp>&rsquo;</dt>
<dt> &lsquo;<samp>srtp_out_params</samp>&rsquo;</dt>
<dd><p>Set input and output encoding parameters, which are expressed by a
base64-encoded representation of a binary block. The first 16 bytes of
this binary block are used as master key, the following 14 bytes are
used as master salt.
</p></dd>
</dl>
<a name="subfile"></a>
<h2 class="section"><a href="ffplay-all.html#toc-subfile">16.28 subfile</a></h2>
<p>Virtually extract a segment of a file or another stream.
The underlying stream must be seekable.
</p>
<p>Accepted options:
</p><dl compact="compact">
<dt> &lsquo;<samp>start</samp>&rsquo;</dt>
<dd><p>Start offset of the extracted segment, in bytes.
</p></dd>
<dt> &lsquo;<samp>end</samp>&rsquo;</dt>
<dd><p>End offset of the extracted segment, in bytes.
</p></dd>
</dl>
<p>Examples:
</p>
<p>Extract a chapter from a DVD VOB file (start and end sectors obtained
externally and multiplied by 2048):
</p><table><tr><td>&nbsp;</td><td><pre class="example">subfile,,start,153391104,end,268142592,,:/media/dvd/VIDEO_TS/VTS_08_1.VOB
</pre></td></tr></table>
<p>Play an AVI file directly from a TAR archive:
subfile,,start,183241728,end,366490624,,:archive.tar
</p>
<a name="tcp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-tcp">16.29 tcp</a></h2>
<p>Transmission Control Protocol.
</p>
<p>The required syntax for a TCP url is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">tcp://<var>hostname</var>:<var>port</var>[?<var>options</var>]
</pre></td></tr></table>
<p><var>options</var> contains a list of &amp;-separated options of the form
<var>key</var>=<var>val</var>.
</p>
<p>The list of supported options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>listen=<var>1|0</var></samp>&rsquo;</dt>
<dd><p>Listen for an incoming connection. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>timeout=<var>microseconds</var></samp>&rsquo;</dt>
<dd><p>Set raise error timeout, expressed in microseconds.
</p>
<p>This option is only relevant in read mode: if no data arrived in more
than this time interval, raise error.
</p>
</dd>
<dt> &lsquo;<samp>listen_timeout=<var>microseconds</var></samp>&rsquo;</dt>
<dd><p>Set listen timeout, expressed in microseconds.
</p></dd>
</dl>
<p>The following example shows how to setup a listening TCP connection
with <code>ffmpeg</code>, which is then accessed with <code>ffplay</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i <var>input</var> -f <var>format</var> tcp://<var>hostname</var>:<var>port</var>?listen
ffplay tcp://<var>hostname</var>:<var>port</var>
</pre></td></tr></table>
<a name="tls"></a>
<h2 class="section"><a href="ffplay-all.html#toc-tls">16.30 tls</a></h2>
<p>Transport Layer Security (TLS) / Secure Sockets Layer (SSL)
</p>
<p>The required syntax for a TLS/SSL url is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">tls://<var>hostname</var>:<var>port</var>[?<var>options</var>]
</pre></td></tr></table>
<p>The following parameters can be set via command line options
(or in code via <code>AVOption</code>s):
</p>
<dl compact="compact">
<dt> &lsquo;<samp>ca_file, cafile=<var>filename</var></samp>&rsquo;</dt>
<dd><p>A file containing certificate authority (CA) root certificates to treat
as trusted. If the linked TLS library contains a default this might not
need to be specified for verification to work, but not all libraries and
setups have defaults built in.
The file must be in OpenSSL PEM format.
</p>
</dd>
<dt> &lsquo;<samp>tls_verify=<var>1|0</var></samp>&rsquo;</dt>
<dd><p>If enabled, try to verify the peer that we are communicating with.
Note, if using OpenSSL, this currently only makes sure that the
peer certificate is signed by one of the root certificates in the CA
database, but it does not validate that the certificate actually
matches the host name we are trying to connect to. (With GnuTLS,
the host name is validated as well.)
</p>
<p>This is disabled by default since it requires a CA database to be
provided by the caller in many cases.
</p>
</dd>
<dt> &lsquo;<samp>cert_file, cert=<var>filename</var></samp>&rsquo;</dt>
<dd><p>A file containing a certificate to use in the handshake with the peer.
(When operating as server, in listen mode, this is more often required
by the peer, while client certificates only are mandated in certain
setups.)
</p>
</dd>
<dt> &lsquo;<samp>key_file, key=<var>filename</var></samp>&rsquo;</dt>
<dd><p>A file containing the private key for the certificate.
</p>
</dd>
<dt> &lsquo;<samp>listen=<var>1|0</var></samp>&rsquo;</dt>
<dd><p>If enabled, listen for connections on the provided port, and assume
the server role in the handshake instead of the client role.
</p>
</dd>
</dl>
<p>Example command lines:
</p>
<p>To create a TLS/SSL server that serves an input stream.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i <var>input</var> -f <var>format</var> tls://<var>hostname</var>:<var>port</var>?listen&amp;cert=<var>server.crt</var>&amp;key=<var>server.key</var>
</pre></td></tr></table>
<p>To play back a stream from the TLS/SSL server using <code>ffplay</code>:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay tls://<var>hostname</var>:<var>port</var>
</pre></td></tr></table>
<a name="udp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-udp">16.31 udp</a></h2>
<p>User Datagram Protocol.
</p>
<p>The required syntax for an UDP URL is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">udp://<var>hostname</var>:<var>port</var>[?<var>options</var>]
</pre></td></tr></table>
<p><var>options</var> contains a list of &amp;-separated options of the form <var>key</var>=<var>val</var>.
</p>
<p>In case threading is enabled on the system, a circular buffer is used
to store the incoming data, which allows one to reduce loss of data due to
UDP socket buffer overruns. The <var>fifo_size</var> and
<var>overrun_nonfatal</var> options are related to this buffer.
</p>
<p>The list of supported options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>buffer_size=<var>size</var></samp>&rsquo;</dt>
<dd><p>Set the UDP maximum socket buffer size in bytes. This is used to set either
the receive or send buffer size, depending on what the socket is used for.
Default is 64KB. See also <var>fifo_size</var>.
</p>
</dd>
<dt> &lsquo;<samp>localport=<var>port</var></samp>&rsquo;</dt>
<dd><p>Override the local UDP port to bind with.
</p>
</dd>
<dt> &lsquo;<samp>localaddr=<var>addr</var></samp>&rsquo;</dt>
<dd><p>Choose the local IP address. This is useful e.g. if sending multicast
and the host has multiple interfaces, where the user can choose
which interface to send on by specifying the IP address of that interface.
</p>
</dd>
<dt> &lsquo;<samp>pkt_size=<var>size</var></samp>&rsquo;</dt>
<dd><p>Set the size in bytes of UDP packets.
</p>
</dd>
<dt> &lsquo;<samp>reuse=<var>1|0</var></samp>&rsquo;</dt>
<dd><p>Explicitly allow or disallow reusing UDP sockets.
</p>
</dd>
<dt> &lsquo;<samp>ttl=<var>ttl</var></samp>&rsquo;</dt>
<dd><p>Set the time to live value (for multicast only).
</p>
</dd>
<dt> &lsquo;<samp>connect=<var>1|0</var></samp>&rsquo;</dt>
<dd><p>Initialize the UDP socket with <code>connect()</code>. In this case, the
destination address can&rsquo;t be changed with ff_udp_set_remote_url later.
If the destination address isn&rsquo;t known at the start, this option can
be specified in ff_udp_set_remote_url, too.
This allows finding out the source address for the packets with getsockname,
and makes writes return with AVERROR(ECONNREFUSED) if &quot;destination
unreachable&quot; is received.
For receiving, this gives the benefit of only receiving packets from
the specified peer address/port.
</p>
</dd>
<dt> &lsquo;<samp>sources=<var>address</var>[,<var>address</var>]</samp>&rsquo;</dt>
<dd><p>Only receive packets sent to the multicast group from one of the
specified sender IP addresses.
</p>
</dd>
<dt> &lsquo;<samp>block=<var>address</var>[,<var>address</var>]</samp>&rsquo;</dt>
<dd><p>Ignore packets sent to the multicast group from the specified
sender IP addresses.
</p>
</dd>
<dt> &lsquo;<samp>fifo_size=<var>units</var></samp>&rsquo;</dt>
<dd><p>Set the UDP receiving circular buffer size, expressed as a number of
packets with size of 188 bytes. If not specified defaults to 7*4096.
</p>
</dd>
<dt> &lsquo;<samp>overrun_nonfatal=<var>1|0</var></samp>&rsquo;</dt>
<dd><p>Survive in case of UDP receiving circular buffer overrun. Default
value is 0.
</p>
</dd>
<dt> &lsquo;<samp>timeout=<var>microseconds</var></samp>&rsquo;</dt>
<dd><p>Set raise error timeout, expressed in microseconds.
</p>
<p>This option is only relevant in read mode: if no data arrived in more
than this time interval, raise error.
</p></dd>
</dl>
<a name="Examples-44"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-44">16.31.1 Examples</a></h3>
<ul>
<li>
Use <code>ffmpeg</code> to stream over UDP to a remote endpoint:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i <var>input</var> -f <var>format</var> udp://<var>hostname</var>:<var>port</var>
</pre></td></tr></table>
</li><li>
Use <code>ffmpeg</code> to stream in mpegts format over UDP using 188
sized UDP packets, using a large input buffer:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i <var>input</var> -f mpegts udp://<var>hostname</var>:<var>port</var>?pkt_size=188&amp;buffer_size=65535
</pre></td></tr></table>
</li><li>
Use <code>ffmpeg</code> to receive over UDP from a remote endpoint:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i udp://[<var>multicast-address</var>]:<var>port</var> ...
</pre></td></tr></table>
</li></ul>
<a name="unix"></a>
<h2 class="section"><a href="ffplay-all.html#toc-unix">16.32 unix</a></h2>
<p>Unix local socket
</p>
<p>The required syntax for a Unix socket URL is:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">unix://<var>filepath</var>
</pre></td></tr></table>
<p>The following parameters can be set via command line options
(or in code via <code>AVOption</code>s):
</p>
<dl compact="compact">
<dt> &lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Timeout in ms.
</p></dd>
<dt> &lsquo;<samp>listen</samp>&rsquo;</dt>
<dd><p>Create the Unix socket in listening mode.
</p></dd>
</dl>
<a name="Device-Options"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Device-Options">17. Device Options</a></h1>
<p>The libavdevice library provides the same interface as
libavformat. Namely, an input device is considered like a demuxer, and
an output device like a muxer, and the interface and generic device
options are the same provided by libavformat (see the ffmpeg-formats
manual).
</p>
<p>In addition each input or output device may support so-called private
options, which are specific for that component.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools, or by setting the value explicitly in the device
<code>AVFormatContext</code> options or using the &lsquo;<tt>libavutil/opt.h</tt>&rsquo; API
for programmatic use.
</p>
<a name="Input-Devices"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Input-Devices">18. Input Devices</a></h1>
<p>Input devices are configured elements in FFmpeg which allow to access
the data coming from a multimedia device attached to your system.
</p>
<p>When you configure your FFmpeg build, all the supported input devices
are enabled by default. You can list all available ones using the
configure option &quot;&ndash;list-indevs&quot;.
</p>
<p>You can disable all the input devices using the configure option
&quot;&ndash;disable-indevs&quot;, and selectively enable an input device using the
option &quot;&ndash;enable-indev=<var>INDEV</var>&quot;, or you can disable a particular
input device using the option &quot;&ndash;disable-indev=<var>INDEV</var>&quot;.
</p>
<p>The option &quot;-formats&quot; of the ff* tools will display the list of
supported input devices (amongst the demuxers).
</p>
<p>A description of the currently available input devices follows.
</p>
<a name="alsa"></a>
<h2 class="section"><a href="ffplay-all.html#toc-alsa">18.1 alsa</a></h2>
<p>ALSA (Advanced Linux Sound Architecture) input device.
</p>
<p>To enable this input device during configuration you need libasound
installed on your system.
</p>
<p>This device allows capturing from an ALSA device. The name of the
device to capture has to be an ALSA card identifier.
</p>
<p>An ALSA identifier has the syntax:
</p><table><tr><td>&nbsp;</td><td><pre class="example">hw:<var>CARD</var>[,<var>DEV</var>[,<var>SUBDEV</var>]]
</pre></td></tr></table>
<p>where the <var>DEV</var> and <var>SUBDEV</var> components are optional.
</p>
<p>The three arguments (in order: <var>CARD</var>,<var>DEV</var>,<var>SUBDEV</var>)
specify card number or identifier, device number and subdevice number
(-1 means any).
</p>
<p>To see the list of cards currently recognized by your system check the
files &lsquo;<tt>/proc/asound/cards</tt>&rsquo; and &lsquo;<tt>/proc/asound/devices</tt>&rsquo;.
</p>
<p>For example to capture with <code>ffmpeg</code> from an ALSA device with
card id 0, you may run the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f alsa -i hw:0 alsaout.wav
</pre></td></tr></table>
<p>For more information see:
<a href="http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html">http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html</a>
</p>
<a name="bktr"></a>
<h2 class="section"><a href="ffplay-all.html#toc-bktr">18.2 bktr</a></h2>
<p>BSD video input device.
</p>
<a name="dshow"></a>
<h2 class="section"><a href="ffplay-all.html#toc-dshow">18.3 dshow</a></h2>
<p>Windows DirectShow input device.
</p>
<p>DirectShow support is enabled when FFmpeg is built with the mingw-w64 project.
Currently only audio and video devices are supported.
</p>
<p>Multiple devices may be opened as separate inputs, but they may also be
opened on the same input, which should improve synchronism between them.
</p>
<p>The input name should be in the format:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example"><var>TYPE</var>=<var>NAME</var>[:<var>TYPE</var>=<var>NAME</var>]
</pre></td></tr></table>
<p>where <var>TYPE</var> can be either <var>audio</var> or <var>video</var>,
and <var>NAME</var> is the device&rsquo;s name.
</p>
<a name="Options-6"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-6">18.3.1 Options</a></h3>
<p>If no options are specified, the device&rsquo;s defaults are used.
If the device does not support the requested options, it will
fail to open.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Set the video size in the captured video.
</p>
</dd>
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Set the frame rate in the captured video.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate</samp>&rsquo;</dt>
<dd><p>Set the sample rate (in Hz) of the captured audio.
</p>
</dd>
<dt> &lsquo;<samp>sample_size</samp>&rsquo;</dt>
<dd><p>Set the sample size (in bits) of the captured audio.
</p>
</dd>
<dt> &lsquo;<samp>channels</samp>&rsquo;</dt>
<dd><p>Set the number of channels in the captured audio.
</p>
</dd>
<dt> &lsquo;<samp>list_devices</samp>&rsquo;</dt>
<dd><p>If set to &lsquo;<samp>true</samp>&rsquo;, print a list of devices and exit.
</p>
</dd>
<dt> &lsquo;<samp>list_options</samp>&rsquo;</dt>
<dd><p>If set to &lsquo;<samp>true</samp>&rsquo;, print a list of selected device&rsquo;s options
and exit.
</p>
</dd>
<dt> &lsquo;<samp>video_device_number</samp>&rsquo;</dt>
<dd><p>Set video device number for devices with same name (starts at 0,
defaults to 0).
</p>
</dd>
<dt> &lsquo;<samp>audio_device_number</samp>&rsquo;</dt>
<dd><p>Set audio device number for devices with same name (starts at 0,
defaults to 0).
</p>
</dd>
<dt> &lsquo;<samp>pixel_format</samp>&rsquo;</dt>
<dd><p>Select pixel format to be used by DirectShow. This may only be set when
the video codec is not set or set to rawvideo.
</p>
</dd>
<dt> &lsquo;<samp>audio_buffer_size</samp>&rsquo;</dt>
<dd><p>Set audio device buffer size in milliseconds (which can directly
impact latency, depending on the device).
Defaults to using the audio device&rsquo;s
default buffer size (typically some multiple of 500ms).
Setting this value too low can degrade performance.
See also
<a href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx">http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx</a>
</p>
</dd>
</dl>
<a name="Examples-28"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-28">18.3.2 Examples</a></h3>
<ul>
<li>
Print the list of DirectShow supported devices and exit:
<table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -list_devices true -f dshow -i dummy
</pre></td></tr></table>
</li><li>
Open video device <var>Camera</var>:
<table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -f dshow -i video=&quot;Camera&quot;
</pre></td></tr></table>
</li><li>
Open second video device with name <var>Camera</var>:
<table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -f dshow -video_device_number 1 -i video=&quot;Camera&quot;
</pre></td></tr></table>
</li><li>
Open video device <var>Camera</var> and audio device <var>Microphone</var>:
<table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -f dshow -i video=&quot;Camera&quot;:audio=&quot;Microphone&quot;
</pre></td></tr></table>
</li><li>
Print the list of supported options in selected device and exit:
<table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -list_options true -f dshow -i video=&quot;Camera&quot;
</pre></td></tr></table>
</li></ul>
<a name="dv1394"></a>
<h2 class="section"><a href="ffplay-all.html#toc-dv1394">18.4 dv1394</a></h2>
<p>Linux DV 1394 input device.
</p>
<a name="fbdev"></a>
<h2 class="section"><a href="ffplay-all.html#toc-fbdev">18.5 fbdev</a></h2>
<p>Linux framebuffer input device.
</p>
<p>The Linux framebuffer is a graphic hardware-independent abstraction
layer to show graphics on a computer monitor, typically on the
console. It is accessed through a file device node, usually
&lsquo;<tt>/dev/fb0</tt>&rsquo;.
</p>
<p>For more detailed information read the file
Documentation/fb/framebuffer.txt included in the Linux source tree.
</p>
<p>To record from the framebuffer device &lsquo;<tt>/dev/fb0</tt>&rsquo; with
<code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
</pre></td></tr></table>
<p>You can take a single screenshot image with the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
</pre></td></tr></table>
<p>See also <a href="http://linux-fbdev.sourceforge.net/">http://linux-fbdev.sourceforge.net/</a>, and fbset(1).
</p>
<a name="gdigrab"></a>
<h2 class="section"><a href="ffplay-all.html#toc-gdigrab">18.6 gdigrab</a></h2>
<p>Win32 GDI-based screen capture device.
</p>
<p>This device allows you to capture a region of the display on Windows.
</p>
<p>There are two options for the input filename:
</p><table><tr><td>&nbsp;</td><td><pre class="example">desktop
</pre></td></tr></table>
<p>or
</p><table><tr><td>&nbsp;</td><td><pre class="example">title=<var>window_title</var>
</pre></td></tr></table>
<p>The first option will capture the entire desktop, or a fixed region of the
desktop. The second option will instead capture the contents of a single
window, regardless of its position on the screen.
</p>
<p>For example, to grab the entire desktop using <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
</pre></td></tr></table>
<p>Grab a 640x480 region at position <code>10,20</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg
</pre></td></tr></table>
<p>Grab the contents of the window named &quot;Calculator&quot;
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg
</pre></td></tr></table>
<a name="Options-4"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-4">18.6.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>draw_mouse</samp>&rsquo;</dt>
<dd><p>Specify whether to draw the mouse pointer. Use the value <code>0</code> to
not draw the pointer. Default value is <code>1</code>.
</p>
</dd>
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Set the grabbing frame rate. Default value is <code>ntsc</code>,
corresponding to a frame rate of <code>30000/1001</code>.
</p>
</dd>
<dt> &lsquo;<samp>show_region</samp>&rsquo;</dt>
<dd><p>Show grabbed region on screen.
</p>
<p>If <var>show_region</var> is specified with <code>1</code>, then the grabbing
region will be indicated on screen. With this option, it is easy to
know what is being grabbed if only a portion of the screen is grabbed.
</p>
<p>Note that <var>show_region</var> is incompatible with grabbing the contents
of a single window.
</p>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Set the video frame size. The default is to capture the full screen if &lsquo;<tt>desktop</tt>&rsquo; is selected, or the full window size if &lsquo;<tt>title=<var>window_title</var></tt>&rsquo; is selected.
</p>
</dd>
<dt> &lsquo;<samp>offset_x</samp>&rsquo;</dt>
<dd><p>When capturing a region with <var>video_size</var>, set the distance from the left edge of the screen or desktop.
</p>
<p>Note that the offset calculation is from the top left corner of the primary monitor on Windows. If you have a monitor positioned to the left of your primary monitor, you will need to use a negative <var>offset_x</var> value to move the region to that monitor.
</p>
</dd>
<dt> &lsquo;<samp>offset_y</samp>&rsquo;</dt>
<dd><p>When capturing a region with <var>video_size</var>, set the distance from the top edge of the screen or desktop.
</p>
<p>Note that the offset calculation is from the top left corner of the primary monitor on Windows. If you have a monitor positioned above your primary monitor, you will need to use a negative <var>offset_y</var> value to move the region to that monitor.
</p>
</dd>
</dl>
<a name="iec61883"></a>
<h2 class="section"><a href="ffplay-all.html#toc-iec61883">18.7 iec61883</a></h2>
<p>FireWire DV/HDV input device using libiec61883.
</p>
<p>To enable this input device, you need libiec61883, libraw1394 and
libavc1394 installed on your system. Use the configure option
<code>--enable-libiec61883</code> to compile with the device enabled.
</p>
<p>The iec61883 capture device supports capturing from a video device
connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
FireWire stack (juju). This is the default DV/HDV input method in Linux
Kernel 2.6.37 and later, since the old FireWire stack was removed.
</p>
<p>Specify the FireWire port to be used as input file, or &quot;auto&quot;
to choose the first port connected.
</p>
<a name="Options"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options">18.7.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>dvtype</samp>&rsquo;</dt>
<dd><p>Override autodetection of DV/HDV. This should only be used if auto
detection does not work, or if usage of a different device type
should be prohibited. Treating a DV device as HDV (or vice versa) will
not work and result in undefined behavior.
The values &lsquo;<samp>auto</samp>&rsquo;, &lsquo;<samp>dv</samp>&rsquo; and &lsquo;<samp>hdv</samp>&rsquo; are supported.
</p>
</dd>
<dt> &lsquo;<samp>dvbuffer</samp>&rsquo;</dt>
<dd><p>Set maxiumum size of buffer for incoming data, in frames. For DV, this
is an exact value. For HDV, it is not frame exact, since HDV does
not have a fixed frame size.
</p>
</dd>
<dt> &lsquo;<samp>dvguid</samp>&rsquo;</dt>
<dd><p>Select the capture device by specifying it&rsquo;s GUID. Capturing will only
be performed from the specified device and fails if no device with the
given GUID is found. This is useful to select the input if multiple
devices are connected at the same time.
Look at /sys/bus/firewire/devices to find out the GUIDs.
</p>
</dd>
</dl>
<a name="Examples-62"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-62">18.7.2 Examples</a></h3>
<ul>
<li>
Grab and show the input of a FireWire DV/HDV device.
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f iec61883 -i auto
</pre></td></tr></table>
</li><li>
Grab and record the input of a FireWire DV/HDV device,
using a packet buffer of 100000 packets if the source is HDV.
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
</pre></td></tr></table>
</li></ul>
<a name="jack"></a>
<h2 class="section"><a href="ffplay-all.html#toc-jack">18.8 jack</a></h2>
<p>JACK input device.
</p>
<p>To enable this input device during configuration you need libjack
installed on your system.
</p>
<p>A JACK input device creates one or more JACK writable clients, one for
each audio channel, with name <var>client_name</var>:input_<var>N</var>, where
<var>client_name</var> is the name provided by the application, and <var>N</var>
is a number which identifies the channel.
Each writable client will send the acquired data to the FFmpeg input
device.
</p>
<p>Once you have created one or more JACK readable clients, you need to
connect them to one or more JACK writable clients.
</p>
<p>To connect or disconnect JACK clients you can use the <code>jack_connect</code>
and <code>jack_disconnect</code> programs, or do it through a graphical interface,
for example with <code>qjackctl</code>.
</p>
<p>To list the JACK clients and their properties you can invoke the command
<code>jack_lsp</code>.
</p>
<p>Follows an example which shows how to capture a JACK readable client
with <code>ffmpeg</code>.
</p><table><tr><td>&nbsp;</td><td><pre class="example"># Create a JACK writable client with name &quot;ffmpeg&quot;.
$ ffmpeg -f jack -i ffmpeg -y out.wav
# Start the sample jack_metro readable client.
$ jack_metro -b 120 -d 0.2 -f 4000
# List the current JACK clients.
$ jack_lsp -c
system:capture_1
system:capture_2
system:playback_1
system:playback_2
ffmpeg:input_1
metro:120_bpm
# Connect metro to the ffmpeg writable client.
$ jack_connect metro:120_bpm ffmpeg:input_1
</pre></td></tr></table>
<p>For more information read:
<a href="http://jackaudio.org/">http://jackaudio.org/</a>
</p>
<a name="lavfi"></a>
<h2 class="section"><a href="ffplay-all.html#toc-lavfi">18.9 lavfi</a></h2>
<p>Libavfilter input virtual device.
</p>
<p>This input device reads data from the open output pads of a libavfilter
filtergraph.
</p>
<p>For each filtergraph open output, the input device will create a
corresponding stream which is mapped to the generated output. Currently
only video data is supported. The filtergraph is specified through the
option &lsquo;<samp>graph</samp>&rsquo;.
</p>
<a name="Options-7"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-7">18.9.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>graph</samp>&rsquo;</dt>
<dd><p>Specify the filtergraph to use as input. Each video open output must be
labelled by a unique string of the form &quot;out<var>N</var>&quot;, where <var>N</var> is a
number starting from 0 corresponding to the mapped input stream
generated by the device.
The first unlabelled output is automatically assigned to the &quot;out0&quot;
label, but all the others need to be specified explicitly.
</p>
<p>If not specified defaults to the filename specified for the input
device.
</p>
</dd>
<dt> &lsquo;<samp>graph_file</samp>&rsquo;</dt>
<dd><p>Set the filename of the filtergraph to be read and sent to the other
filters. Syntax of the filtergraph is the same as the one specified by
the option <var>graph</var>.
</p>
</dd>
</dl>
<a name="Examples-46"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-46">18.9.2 Examples</a></h3>
<ul>
<li>
Create a color video stream and play it back with <code>ffplay</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi -graph &quot;color=c=pink [out0]&quot; dummy
</pre></td></tr></table>
</li><li>
As the previous example, but use filename for specifying the graph
description, and omit the &quot;out0&quot; label:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi color=c=pink
</pre></td></tr></table>
</li><li>
Create three different video test filtered sources and play them:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi -graph &quot;testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]&quot; test3
</pre></td></tr></table>
</li><li>
Read an audio stream from a file using the amovie source and play it
back with <code>ffplay</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi &quot;amovie=test.wav&quot;
</pre></td></tr></table>
</li><li>
Read an audio stream and a video stream and play it back with
<code>ffplay</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi &quot;movie=test.avi[out0];amovie=test.wav[out1]&quot;
</pre></td></tr></table>
</li></ul>
<a name="libdc1394"></a>
<h2 class="section"><a href="ffplay-all.html#toc-libdc1394">18.10 libdc1394</a></h2>
<p>IIDC1394 input device, based on libdc1394 and libraw1394.
</p>
<a name="openal"></a>
<h2 class="section"><a href="ffplay-all.html#toc-openal">18.11 openal</a></h2>
<p>The OpenAL input device provides audio capture on all systems with a
working OpenAL 1.1 implementation.
</p>
<p>To enable this input device during configuration, you need OpenAL
headers and libraries installed on your system, and need to configure
FFmpeg with <code>--enable-openal</code>.
</p>
<p>OpenAL headers and libraries should be provided as part of your OpenAL
implementation, or as an additional download (an SDK). Depending on your
installation you may need to specify additional flags via the
<code>--extra-cflags</code> and <code>--extra-ldflags</code> for allowing the build
system to locate the OpenAL headers and libraries.
</p>
<p>An incomplete list of OpenAL implementations follows:
</p>
<dl compact="compact">
<dt> <strong>Creative</strong></dt>
<dd><p>The official Windows implementation, providing hardware acceleration
with supported devices and software fallback.
See <a href="http://openal.org/">http://openal.org/</a>.
</p></dd>
<dt> <strong>OpenAL Soft</strong></dt>
<dd><p>Portable, open source (LGPL) software implementation. Includes
backends for the most common sound APIs on the Windows, Linux,
Solaris, and BSD operating systems.
See <a href="http://kcat.strangesoft.net/openal.html">http://kcat.strangesoft.net/openal.html</a>.
</p></dd>
<dt> <strong>Apple</strong></dt>
<dd><p>OpenAL is part of Core Audio, the official Mac OS X Audio interface.
See <a href="http://developer.apple.com/technologies/mac/audio-and-video.html">http://developer.apple.com/technologies/mac/audio-and-video.html</a>
</p></dd>
</dl>
<p>This device allows one to capture from an audio input device handled
through OpenAL.
</p>
<p>You need to specify the name of the device to capture in the provided
filename. If the empty string is provided, the device will
automatically select the default device. You can get the list of the
supported devices by using the option <var>list_devices</var>.
</p>
<a name="Options-8"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-8">18.11.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>channels</samp>&rsquo;</dt>
<dd><p>Set the number of channels in the captured audio. Only the values
&lsquo;<samp>1</samp>&rsquo; (monaural) and &lsquo;<samp>2</samp>&rsquo; (stereo) are currently supported.
Defaults to &lsquo;<samp>2</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>sample_size</samp>&rsquo;</dt>
<dd><p>Set the sample size (in bits) of the captured audio. Only the values
&lsquo;<samp>8</samp>&rsquo; and &lsquo;<samp>16</samp>&rsquo; are currently supported. Defaults to
&lsquo;<samp>16</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate</samp>&rsquo;</dt>
<dd><p>Set the sample rate (in Hz) of the captured audio.
Defaults to &lsquo;<samp>44.1k</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>list_devices</samp>&rsquo;</dt>
<dd><p>If set to &lsquo;<samp>true</samp>&rsquo;, print a list of devices and exit.
Defaults to &lsquo;<samp>false</samp>&rsquo;.
</p>
</dd>
</dl>
<a name="Examples-5"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-5">18.11.2 Examples</a></h3>
<p>Print the list of OpenAL supported devices and exit:
</p><table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -list_devices true -f openal -i dummy out.ogg
</pre></td></tr></table>
<p>Capture from the OpenAL device &lsquo;<tt>DR-BT101 via PulseAudio</tt>&rsquo;:
</p><table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
</pre></td></tr></table>
<p>Capture from the default device (note the empty string &rdquo; as filename):
</p><table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -f openal -i '' out.ogg
</pre></td></tr></table>
<p>Capture from two devices simultaneously, writing to two different files,
within the same <code>ffmpeg</code> command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
</pre></td></tr></table>
<p>Note: not all OpenAL implementations support multiple simultaneous capture -
try the latest OpenAL Soft if the above does not work.
</p>
<a name="oss"></a>
<h2 class="section"><a href="ffplay-all.html#toc-oss">18.12 oss</a></h2>
<p>Open Sound System input device.
</p>
<p>The filename to provide to the input device is the device node
representing the OSS input device, and is usually set to
&lsquo;<tt>/dev/dsp</tt>&rsquo;.
</p>
<p>For example to grab from &lsquo;<tt>/dev/dsp</tt>&rsquo; using <code>ffmpeg</code> use the
command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
</pre></td></tr></table>
<p>For more information about OSS see:
<a href="http://manuals.opensound.com/usersguide/dsp.html">http://manuals.opensound.com/usersguide/dsp.html</a>
</p>
<a name="pulse"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pulse">18.13 pulse</a></h2>
<p>PulseAudio input device.
</p>
<p>To enable this output device you need to configure FFmpeg with <code>--enable-libpulse</code>.
</p>
<p>The filename to provide to the input device is a source device or the
string &quot;default&quot;
</p>
<p>To list the PulseAudio source devices and their properties you can invoke
the command <code>pactl list sources</code>.
</p>
<p>More information about PulseAudio can be found on <a href="http://www.pulseaudio.org">http://www.pulseaudio.org</a>.
</p>
<a name="Options-11"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-11">18.13.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>server</samp>&rsquo;</dt>
<dd><p>Connect to a specific PulseAudio server, specified by an IP address.
Default server is used when not provided.
</p>
</dd>
<dt> &lsquo;<samp>name</samp>&rsquo;</dt>
<dd><p>Specify the application name PulseAudio will use when showing active clients,
by default it is the <code>LIBAVFORMAT_IDENT</code> string.
</p>
</dd>
<dt> &lsquo;<samp>stream_name</samp>&rsquo;</dt>
<dd><p>Specify the stream name PulseAudio will use when showing active streams,
by default it is &quot;record&quot;.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate</samp>&rsquo;</dt>
<dd><p>Specify the samplerate in Hz, by default 48kHz is used.
</p>
</dd>
<dt> &lsquo;<samp>channels</samp>&rsquo;</dt>
<dd><p>Specify the channels in use, by default 2 (stereo) is set.
</p>
</dd>
<dt> &lsquo;<samp>frame_size</samp>&rsquo;</dt>
<dd><p>Specify the number of bytes per frame, by default it is set to 1024.
</p>
</dd>
<dt> &lsquo;<samp>fragment_size</samp>&rsquo;</dt>
<dd><p>Specify the minimal buffering fragment in PulseAudio, it will affect the
audio latency. By default it is unset.
</p></dd>
</dl>
<a name="Examples-61"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-61">18.13.2 Examples</a></h3>
<p>Record a stream from default device:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f pulse -i default /tmp/pulse.wav
</pre></td></tr></table>
<a name="qtkit"></a>
<h2 class="section"><a href="ffplay-all.html#toc-qtkit">18.14 qtkit</a></h2>
<p>QTKit input device.
</p>
<p>The filename passed as input is parsed to contain either a device name or index.
The device index can also be given by using -video_device_index.
A given device index will override any given device name.
If the desired device consists of numbers only, use -video_device_index to identify it.
The default device will be chosen if an empty string or the device name &quot;default&quot; is given.
The available devices can be enumerated by using -list_devices.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f qtkit -i &quot;0&quot; out.mpg
</pre></td></tr></table>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f qtkit -video_device_index 0 -i &quot;&quot; out.mpg
</pre></td></tr></table>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f qtkit -i &quot;default&quot; out.mpg
</pre></td></tr></table>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f qtkit -list_devices true -i &quot;&quot;
</pre></td></tr></table>
<a name="sndio"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sndio">18.15 sndio</a></h2>
<p>sndio input device.
</p>
<p>To enable this input device during configuration you need libsndio
installed on your system.
</p>
<p>The filename to provide to the input device is the device node
representing the sndio input device, and is usually set to
&lsquo;<tt>/dev/audio0</tt>&rsquo;.
</p>
<p>For example to grab from &lsquo;<tt>/dev/audio0</tt>&rsquo; using <code>ffmpeg</code> use the
command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
</pre></td></tr></table>
<a name="video4linux2_002c-v4l2"></a>
<h2 class="section"><a href="ffplay-all.html#toc-video4linux2_002c-v4l2">18.16 video4linux2, v4l2</a></h2>
<p>Video4Linux2 input video device.
</p>
<p>&quot;v4l2&quot; can be used as alias for &quot;video4linux2&quot;.
</p>
<p>If FFmpeg is built with v4l-utils support (by using the
<code>--enable-libv4l2</code> configure option), it is possible to use it with the
<code>-use_libv4l2</code> input device option.
</p>
<p>The name of the device to grab is a file device node, usually Linux
systems tend to automatically create such nodes when the device
(e.g. an USB webcam) is plugged into the system, and has a name of the
kind &lsquo;<tt>/dev/video<var>N</var></tt>&rsquo;, where <var>N</var> is a number associated to
the device.
</p>
<p>Video4Linux2 devices usually support a limited set of
<var>width</var>x<var>height</var> sizes and frame rates. You can check which are
supported using <code>-list_formats all</code> for Video4Linux2 devices.
Some devices, like TV cards, support one or more standards. It is possible
to list all the supported standards using <code>-list_standards all</code>.
</p>
<p>The time base for the timestamps is 1 microsecond. Depending on the kernel
version and configuration, the timestamps may be derived from the real time
clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
boot time, unaffected by NTP or manual changes to the clock). The
&lsquo;<samp>-timestamps abs</samp>&rsquo; or &lsquo;<samp>-ts abs</samp>&rsquo; option can be used to force
conversion into the real time clock.
</p>
<p>Some usage examples of the video4linux2 device with <code>ffmpeg</code>
and <code>ffplay</code>:
</p><ul>
<li>
Grab and show the input of a video4linux2 device:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
</pre></td></tr></table>
</li><li>
Grab and record the input of a video4linux2 device, leave the
frame rate and size as previously set:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
</pre></td></tr></table>
</li></ul>
<p>For more information about Video4Linux, check <a href="http://linuxtv.org/">http://linuxtv.org/</a>.
</p>
<a name="Options-15"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-15">18.16.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>standard</samp>&rsquo;</dt>
<dd><p>Set the standard. Must be the name of a supported standard. To get a
list of the supported standards, use the &lsquo;<samp>list_standards</samp>&rsquo;
option.
</p>
</dd>
<dt> &lsquo;<samp>channel</samp>&rsquo;</dt>
<dd><p>Set the input channel number. Default to -1, which means using the
previously selected channel.
</p>
</dd>
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Set the video frame size. The argument must be a string in the form
<var>WIDTH</var>x<var>HEIGHT</var> or a valid size abbreviation.
</p>
</dd>
<dt> &lsquo;<samp>pixel_format</samp>&rsquo;</dt>
<dd><p>Select the pixel format (only valid for raw video input).
</p>
</dd>
<dt> &lsquo;<samp>input_format</samp>&rsquo;</dt>
<dd><p>Set the preferred pixel format (for raw video) or a codec name.
This option allows one to select the input format, when several are
available.
</p>
</dd>
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Set the preferred video frame rate.
</p>
</dd>
<dt> &lsquo;<samp>list_formats</samp>&rsquo;</dt>
<dd><p>List available formats (supported pixel formats, codecs, and frame
sizes) and exit.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Show all available (compressed and non-compressed) formats.
</p>
</dd>
<dt> &lsquo;<samp>raw</samp>&rsquo;</dt>
<dd><p>Show only raw video (non-compressed) formats.
</p>
</dd>
<dt> &lsquo;<samp>compressed</samp>&rsquo;</dt>
<dd><p>Show only compressed formats.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>list_standards</samp>&rsquo;</dt>
<dd><p>List supported standards and exit.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Show all supported standards.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>timestamps, ts</samp>&rsquo;</dt>
<dd><p>Set type of timestamps for grabbed frames.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>default</samp>&rsquo;</dt>
<dd><p>Use timestamps from the kernel.
</p>
</dd>
<dt> &lsquo;<samp>abs</samp>&rsquo;</dt>
<dd><p>Use absolute timestamps (wall clock).
</p>
</dd>
<dt> &lsquo;<samp>mono2abs</samp>&rsquo;</dt>
<dd><p>Force conversion from monotonic to absolute timestamps.
</p></dd>
</dl>
<p>Default value is <code>default</code>.
</p></dd>
</dl>
<a name="vfwcap"></a>
<h2 class="section"><a href="ffplay-all.html#toc-vfwcap">18.17 vfwcap</a></h2>
<p>VfW (Video for Windows) capture input device.
</p>
<p>The filename passed as input is the capture driver number, ranging from
0 to 9. You may use &quot;list&quot; as filename to print a list of drivers. Any
other filename will be interpreted as device number 0.
</p>
<a name="x11grab"></a>
<h2 class="section"><a href="ffplay-all.html#toc-x11grab">18.18 x11grab</a></h2>
<p>X11 video input device.
</p>
<p>This device allows one to capture a region of an X11 display.
</p>
<p>The filename passed as input has the syntax:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[<var>hostname</var>]:<var>display_number</var>.<var>screen_number</var>[+<var>x_offset</var>,<var>y_offset</var>]
</pre></td></tr></table>
<p><var>hostname</var>:<var>display_number</var>.<var>screen_number</var> specifies the
X11 display name of the screen to grab from. <var>hostname</var> can be
omitted, and defaults to &quot;localhost&quot;. The environment variable
<code>DISPLAY</code> contains the default display name.
</p>
<p><var>x_offset</var> and <var>y_offset</var> specify the offsets of the grabbed
area with respect to the top-left border of the X11 screen. They
default to 0.
</p>
<p>Check the X11 documentation (e.g. man X) for more detailed information.
</p>
<p>Use the <code>dpyinfo</code> program for getting basic information about the
properties of your X11 display (e.g. grep for &quot;name&quot; or &quot;dimensions&quot;).
</p>
<p>For example to grab from &lsquo;<tt>:0.0</tt>&rsquo; using <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
</pre></td></tr></table>
<p>Grab at position <code>10,20</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
</pre></td></tr></table>
<a name="Options-3"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-3">18.18.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>draw_mouse</samp>&rsquo;</dt>
<dd><p>Specify whether to draw the mouse pointer. A value of <code>0</code> specify
not to draw the pointer. Default value is <code>1</code>.
</p>
</dd>
<dt> &lsquo;<samp>follow_mouse</samp>&rsquo;</dt>
<dd><p>Make the grabbed area follow the mouse. The argument can be
<code>centered</code> or a number of pixels <var>PIXELS</var>.
</p>
<p>When it is specified with &quot;centered&quot;, the grabbing region follows the mouse
pointer and keeps the pointer at the center of region; otherwise, the region
follows only when the mouse pointer reaches within <var>PIXELS</var> (greater than
zero) to the edge of region.
</p>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
</pre></td></tr></table>
<p>To follow only when the mouse pointer reaches within 100 pixels to edge:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Set the grabbing frame rate. Default value is <code>ntsc</code>,
corresponding to a frame rate of <code>30000/1001</code>.
</p>
</dd>
<dt> &lsquo;<samp>show_region</samp>&rsquo;</dt>
<dd><p>Show grabbed region on screen.
</p>
<p>If <var>show_region</var> is specified with <code>1</code>, then the grabbing
region will be indicated on screen. With this option, it is easy to
know what is being grabbed if only a portion of the screen is grabbed.
</p>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
</pre></td></tr></table>
<p>With <var>follow_mouse</var>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Set the video frame size. Default value is <code>vga</code>.
</p></dd>
</dl>
<a name="Resampler-Options"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Resampler-Options">19. Resampler Options</a></h1>
<p>The audio resampler supports the following named options.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools, <var>option</var>=<var>value</var> for the aresample filter,
by setting the value explicitly in the
<code>SwrContext</code> options or using the &lsquo;<tt>libavutil/opt.h</tt>&rsquo; API for
programmatic use.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>ich, in_channel_count</samp>&rsquo;</dt>
<dd><p>Set the number of input channels. Default value is 0. Setting this
value is not mandatory if the corresponding channel layout
&lsquo;<samp>in_channel_layout</samp>&rsquo; is set.
</p>
</dd>
<dt> &lsquo;<samp>och, out_channel_count</samp>&rsquo;</dt>
<dd><p>Set the number of output channels. Default value is 0. Setting this
value is not mandatory if the corresponding channel layout
&lsquo;<samp>out_channel_layout</samp>&rsquo; is set.
</p>
</dd>
<dt> &lsquo;<samp>uch, used_channel_count</samp>&rsquo;</dt>
<dd><p>Set the number of used input channels. Default value is 0. This option is
only used for special remapping.
</p>
</dd>
<dt> &lsquo;<samp>isr, in_sample_rate</samp>&rsquo;</dt>
<dd><p>Set the input sample rate. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>osr, out_sample_rate</samp>&rsquo;</dt>
<dd><p>Set the output sample rate. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>isf, in_sample_fmt</samp>&rsquo;</dt>
<dd><p>Specify the input sample format. It is set by default to <code>none</code>.
</p>
</dd>
<dt> &lsquo;<samp>osf, out_sample_fmt</samp>&rsquo;</dt>
<dd><p>Specify the output sample format. It is set by default to <code>none</code>.
</p>
</dd>
<dt> &lsquo;<samp>tsf, internal_sample_fmt</samp>&rsquo;</dt>
<dd><p>Set the internal sample format. Default value is <code>none</code>.
This will automatically be chosen when it is not explicitly set.
</p>
</dd>
<dt> &lsquo;<samp>icl, in_channel_layout</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ocl, out_channel_layout</samp>&rsquo;</dt>
<dd><p>Set the input/output channel layout.
</p>
<p>See <a href="ffmpeg-utils.html#channel-layout-syntax">(ffmpeg-utils)channel layout syntax</a>
for the required syntax.
</p>
</dd>
<dt> &lsquo;<samp>clev, center_mix_level</samp>&rsquo;</dt>
<dd><p>Set the center mix level. It is a value expressed in deciBel, and must be
in the interval [-32,32].
</p>
</dd>
<dt> &lsquo;<samp>slev, surround_mix_level</samp>&rsquo;</dt>
<dd><p>Set the surround mix level. It is a value expressed in deciBel, and must
be in the interval [-32,32].
</p>
</dd>
<dt> &lsquo;<samp>lfe_mix_level</samp>&rsquo;</dt>
<dd><p>Set LFE mix into non LFE level. It is used when there is a LFE input but no
LFE output. It is a value expressed in deciBel, and must
be in the interval [-32,32].
</p>
</dd>
<dt> &lsquo;<samp>rmvol, rematrix_volume</samp>&rsquo;</dt>
<dd><p>Set rematrix volume. Default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>rematrix_maxval</samp>&rsquo;</dt>
<dd><p>Set maximum output value for rematrixing.
This can be used to prevent clipping vs. preventing volumn reduction
A value of 1.0 prevents cliping.
</p>
</dd>
<dt> &lsquo;<samp>flags, swr_flags</samp>&rsquo;</dt>
<dd><p>Set flags used by the converter. Default value is 0.
</p>
<p>It supports the following individual flags:
</p><dl compact="compact">
<dt> &lsquo;<samp>res</samp>&rsquo;</dt>
<dd><p>force resampling, this flag forces resampling to be used even when the
input and output sample rates match.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>dither_scale</samp>&rsquo;</dt>
<dd><p>Set the dither scale. Default value is 1.
</p>
</dd>
<dt> &lsquo;<samp>dither_method</samp>&rsquo;</dt>
<dd><p>Set dither method. Default value is 0.
</p>
<p>Supported values:
</p><dl compact="compact">
<dt> &lsquo;<samp>rectangular</samp>&rsquo;</dt>
<dd><p>select rectangular dither
</p></dd>
<dt> &lsquo;<samp>triangular</samp>&rsquo;</dt>
<dd><p>select triangular dither
</p></dd>
<dt> &lsquo;<samp>triangular_hp</samp>&rsquo;</dt>
<dd><p>select triangular dither with high pass
</p></dd>
<dt> &lsquo;<samp>lipshitz</samp>&rsquo;</dt>
<dd><p>select lipshitz noise shaping dither
</p></dd>
<dt> &lsquo;<samp>shibata</samp>&rsquo;</dt>
<dd><p>select shibata noise shaping dither
</p></dd>
<dt> &lsquo;<samp>low_shibata</samp>&rsquo;</dt>
<dd><p>select low shibata noise shaping dither
</p></dd>
<dt> &lsquo;<samp>high_shibata</samp>&rsquo;</dt>
<dd><p>select high shibata noise shaping dither
</p></dd>
<dt> &lsquo;<samp>f_weighted</samp>&rsquo;</dt>
<dd><p>select f-weighted noise shaping dither
</p></dd>
<dt> &lsquo;<samp>modified_e_weighted</samp>&rsquo;</dt>
<dd><p>select modified-e-weighted noise shaping dither
</p></dd>
<dt> &lsquo;<samp>improved_e_weighted</samp>&rsquo;</dt>
<dd><p>select improved-e-weighted noise shaping dither
</p>
</dd>
</dl>
</dd>
<dt> &lsquo;<samp>resampler</samp>&rsquo;</dt>
<dd><p>Set resampling engine. Default value is swr.
</p>
<p>Supported values:
</p><dl compact="compact">
<dt> &lsquo;<samp>swr</samp>&rsquo;</dt>
<dd><p>select the native SW Resampler; filter options precision and cheby are not
applicable in this case.
</p></dd>
<dt> &lsquo;<samp>soxr</samp>&rsquo;</dt>
<dd><p>select the SoX Resampler (where available); compensation, and filter options
filter_size, phase_shift, filter_type &amp; kaiser_beta, are not applicable in this
case.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>filter_size</samp>&rsquo;</dt>
<dd><p>For swr only, set resampling filter size, default value is 32.
</p>
</dd>
<dt> &lsquo;<samp>phase_shift</samp>&rsquo;</dt>
<dd><p>For swr only, set resampling phase shift, default value is 10, and must be in
the interval [0,30].
</p>
</dd>
<dt> &lsquo;<samp>linear_interp</samp>&rsquo;</dt>
<dd><p>Use Linear Interpolation if set to 1, default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>cutoff</samp>&rsquo;</dt>
<dd><p>Set cutoff frequency (swr: 6dB point; soxr: 0dB point) ratio; must be a float
value between 0 and 1. Default value is 0.97 with swr, and 0.91 with soxr
(which, with a sample-rate of 44100, preserves the entire audio band to 20kHz).
</p>
</dd>
<dt> &lsquo;<samp>precision</samp>&rsquo;</dt>
<dd><p>For soxr only, the precision in bits to which the resampled signal will be
calculated. The default value of 20 (which, with suitable dithering, is
appropriate for a destination bit-depth of 16) gives SoX&rsquo;s &rsquo;High Quality&rsquo;; a
value of 28 gives SoX&rsquo;s &rsquo;Very High Quality&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>cheby</samp>&rsquo;</dt>
<dd><p>For soxr only, selects passband rolloff none (Chebyshev) &amp; higher-precision
approximation for &rsquo;irrational&rsquo; ratios. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>async</samp>&rsquo;</dt>
<dd><p>For swr only, simple 1 parameter audio sync to timestamps using stretching,
squeezing, filling and trimming. Setting this to 1 will enable filling and
trimming, larger values represent the maximum amount in samples that the data
may be stretched or squeezed for each second.
Default value is 0, thus no compensation is applied to make the samples match
the audio timestamps.
</p>
</dd>
<dt> &lsquo;<samp>first_pts</samp>&rsquo;</dt>
<dd><p>For swr only, assume the first pts should be this value. The time unit is 1 / sample rate.
This allows for padding/trimming at the start of stream. By default, no
assumption is made about the first frame&rsquo;s expected pts, so no padding or
trimming is done. For example, this could be set to 0 to pad the beginning with
silence if an audio stream starts after the video stream or to trim any samples
with a negative pts due to encoder delay.
</p>
</dd>
<dt> &lsquo;<samp>min_comp</samp>&rsquo;</dt>
<dd><p>For swr only, set the minimum difference between timestamps and audio data (in
seconds) to trigger stretching/squeezing/filling or trimming of the
data to make it match the timestamps. The default is that
stretching/squeezing/filling and trimming is disabled
(&lsquo;<samp>min_comp</samp>&rsquo; = <code>FLT_MAX</code>).
</p>
</dd>
<dt> &lsquo;<samp>min_hard_comp</samp>&rsquo;</dt>
<dd><p>For swr only, set the minimum difference between timestamps and audio data (in
seconds) to trigger adding/dropping samples to make it match the
timestamps. This option effectively is a threshold to select between
hard (trim/fill) and soft (squeeze/stretch) compensation. Note that
all compensation is by default disabled through &lsquo;<samp>min_comp</samp>&rsquo;.
The default is 0.1.
</p>
</dd>
<dt> &lsquo;<samp>comp_duration</samp>&rsquo;</dt>
<dd><p>For swr only, set duration (in seconds) over which data is stretched/squeezed
to make it match the timestamps. Must be a non-negative double float value,
default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>max_soft_comp</samp>&rsquo;</dt>
<dd><p>For swr only, set maximum factor by which data is stretched/squeezed to make it
match the timestamps. Must be a non-negative double float value, default value
is 0.
</p>
</dd>
<dt> &lsquo;<samp>matrix_encoding</samp>&rsquo;</dt>
<dd><p>Select matrixed stereo encoding.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>select none
</p></dd>
<dt> &lsquo;<samp>dolby</samp>&rsquo;</dt>
<dd><p>select Dolby
</p></dd>
<dt> &lsquo;<samp>dplii</samp>&rsquo;</dt>
<dd><p>select Dolby Pro Logic II
</p></dd>
</dl>
<p>Default value is <code>none</code>.
</p>
</dd>
<dt> &lsquo;<samp>filter_type</samp>&rsquo;</dt>
<dd><p>For swr only, select resampling filter type. This only affects resampling
operations.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>cubic</samp>&rsquo;</dt>
<dd><p>select cubic
</p></dd>
<dt> &lsquo;<samp>blackman_nuttall</samp>&rsquo;</dt>
<dd><p>select Blackman Nuttall Windowed Sinc
</p></dd>
<dt> &lsquo;<samp>kaiser</samp>&rsquo;</dt>
<dd><p>select Kaiser Windowed Sinc
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>kaiser_beta</samp>&rsquo;</dt>
<dd><p>For swr only, set Kaiser Window Beta value. Must be an integer in the
interval [2,16], default value is 9.
</p>
</dd>
<dt> &lsquo;<samp>output_sample_bits</samp>&rsquo;</dt>
<dd><p>For swr only, set number of used output sample bits for dithering. Must be an integer in the
interval [0,64], default value is 0, which means it&rsquo;s not used.
</p>
</dd>
</dl>
<p><a name="scaler_005foptions"></a>
</p><a name="Scaler-Options"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Scaler-Options">20. Scaler Options</a></h1>
<p>The video scaler supports the following named options.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools. For programmatic use, they can be set explicitly in the
<code>SwsContext</code> options or through the &lsquo;<tt>libavutil/opt.h</tt>&rsquo; API.
</p>
<dl compact="compact">
<dd>
<p><a name="sws_005fflags"></a>
</p></dd>
<dt> &lsquo;<samp>sws_flags</samp>&rsquo;</dt>
<dd><p>Set the scaler flags. This is also used to set the scaling
algorithm. Only a single algorithm should be selected.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>fast_bilinear</samp>&rsquo;</dt>
<dd><p>Select fast bilinear scaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>bilinear</samp>&rsquo;</dt>
<dd><p>Select bilinear scaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>bicubic</samp>&rsquo;</dt>
<dd><p>Select bicubic scaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>experimental</samp>&rsquo;</dt>
<dd><p>Select experimental scaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>neighbor</samp>&rsquo;</dt>
<dd><p>Select nearest neighbor rescaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>area</samp>&rsquo;</dt>
<dd><p>Select averaging area rescaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>bicublin</samp>&rsquo;</dt>
<dd><p>Select bicubic scaling algorithm for the luma component, bilinear for
chroma components.
</p>
</dd>
<dt> &lsquo;<samp>gauss</samp>&rsquo;</dt>
<dd><p>Select Gaussian rescaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>sinc</samp>&rsquo;</dt>
<dd><p>Select sinc rescaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>lanczos</samp>&rsquo;</dt>
<dd><p>Select lanczos rescaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>spline</samp>&rsquo;</dt>
<dd><p>Select natural bicubic spline rescaling algorithm.
</p>
</dd>
<dt> &lsquo;<samp>print_info</samp>&rsquo;</dt>
<dd><p>Enable printing/debug logging.
</p>
</dd>
<dt> &lsquo;<samp>accurate_rnd</samp>&rsquo;</dt>
<dd><p>Enable accurate rounding.
</p>
</dd>
<dt> &lsquo;<samp>full_chroma_int</samp>&rsquo;</dt>
<dd><p>Enable full chroma interpolation.
</p>
</dd>
<dt> &lsquo;<samp>full_chroma_inp</samp>&rsquo;</dt>
<dd><p>Select full chroma input.
</p>
</dd>
<dt> &lsquo;<samp>bitexact</samp>&rsquo;</dt>
<dd><p>Enable bitexact output.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>srcw</samp>&rsquo;</dt>
<dd><p>Set source width.
</p>
</dd>
<dt> &lsquo;<samp>srch</samp>&rsquo;</dt>
<dd><p>Set source height.
</p>
</dd>
<dt> &lsquo;<samp>dstw</samp>&rsquo;</dt>
<dd><p>Set destination width.
</p>
</dd>
<dt> &lsquo;<samp>dsth</samp>&rsquo;</dt>
<dd><p>Set destination height.
</p>
</dd>
<dt> &lsquo;<samp>src_format</samp>&rsquo;</dt>
<dd><p>Set source pixel format (must be expressed as an integer).
</p>
</dd>
<dt> &lsquo;<samp>dst_format</samp>&rsquo;</dt>
<dd><p>Set destination pixel format (must be expressed as an integer).
</p>
</dd>
<dt> &lsquo;<samp>src_range</samp>&rsquo;</dt>
<dd><p>Select source range.
</p>
</dd>
<dt> &lsquo;<samp>dst_range</samp>&rsquo;</dt>
<dd><p>Select destination range.
</p>
</dd>
<dt> &lsquo;<samp>param0, param1</samp>&rsquo;</dt>
<dd><p>Set scaling algorithm parameters. The specified values are specific of
some scaling algorithms and ignored by others. The specified values
are floating point number values.
</p>
</dd>
<dt> &lsquo;<samp>sws_dither</samp>&rsquo;</dt>
<dd><p>Set the dithering algorithm. Accepts one of the following
values. Default value is &lsquo;<samp>auto</samp>&rsquo;.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>automatic choice
</p>
</dd>
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>no dithering
</p>
</dd>
<dt> &lsquo;<samp>bayer</samp>&rsquo;</dt>
<dd><p>bayer dither
</p>
</dd>
<dt> &lsquo;<samp>ed</samp>&rsquo;</dt>
<dd><p>error diffusion dither
</p>
</dd>
<dt> &lsquo;<samp>a_dither</samp>&rsquo;</dt>
<dd><p>arithmetic dither, based using addition
</p>
</dd>
<dt> &lsquo;<samp>x_dither</samp>&rsquo;</dt>
<dd><p>arithmetic dither, based using xor (more random/less apparent patterning that
a_dither).
</p>
</dd>
</dl>
</dd>
</dl>
<a name="Filtering-Introduction"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Filtering-Introduction">21. Filtering Introduction</a></h1>
<p>Filtering in FFmpeg is enabled through the libavfilter library.
</p>
<p>In libavfilter, a filter can have multiple inputs and multiple
outputs.
To illustrate the sorts of things that are possible, we consider the
following filtergraph.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example"> [main]
input --&gt; split ---------------------&gt; overlay --&gt; output
| ^
|[tmp] [flip]|
+-----&gt; crop --&gt; vflip -------+
</pre></td></tr></table>
<p>This filtergraph splits the input stream in two streams, sends one
stream through the crop filter and the vflip filter before merging it
back with the other stream by overlaying it on top. You can use the
following command to achieve this:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -vf &quot;split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2&quot; OUTPUT
</pre></td></tr></table>
<p>The result will be that in output the top half of the video is mirrored
onto the bottom half.
</p>
<p>Filters in the same linear chain are separated by commas, and distinct
linear chains of filters are separated by semicolons. In our example,
<var>crop,vflip</var> are in one linear chain, <var>split</var> and
<var>overlay</var> are separately in another. The points where the linear
chains join are labelled by names enclosed in square brackets. In the
example, the split filter generates two outputs that are associated to
the labels <var>[main]</var> and <var>[tmp]</var>.
</p>
<p>The stream sent to the second output of <var>split</var>, labelled as
<var>[tmp]</var>, is processed through the <var>crop</var> filter, which crops
away the lower half part of the video, and then vertically flipped. The
<var>overlay</var> filter takes in input the first unchanged output of the
split filter (which was labelled as <var>[main]</var>), and overlay on its
lower half the output generated by the <var>crop,vflip</var> filterchain.
</p>
<p>Some filters take in input a list of parameters: they are specified
after the filter name and an equal sign, and are separated from each other
by a colon.
</p>
<p>There exist so-called <var>source filters</var> that do not have an
audio/video input, and <var>sink filters</var> that will not have audio/video
output.
</p>
<a name="graph2dot"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-graph2dot">22. graph2dot</a></h1>
<p>The &lsquo;<tt>graph2dot</tt>&rsquo; program included in the FFmpeg &lsquo;<tt>tools</tt>&rsquo;
directory can be used to parse a filtergraph description and issue a
corresponding textual representation in the dot language.
</p>
<p>Invoke the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">graph2dot -h
</pre></td></tr></table>
<p>to see how to use &lsquo;<tt>graph2dot</tt>&rsquo;.
</p>
<p>You can then pass the dot description to the &lsquo;<tt>dot</tt>&rsquo; program (from
the graphviz suite of programs) and obtain a graphical representation
of the filtergraph.
</p>
<p>For example the sequence of commands:
</p><table><tr><td>&nbsp;</td><td><pre class="example">echo <var>GRAPH_DESCRIPTION</var> | \
tools/graph2dot -o graph.tmp &amp;&amp; \
dot -Tpng graph.tmp -o graph.png &amp;&amp; \
display graph.png
</pre></td></tr></table>
<p>can be used to create and display an image representing the graph
described by the <var>GRAPH_DESCRIPTION</var> string. Note that this string must be
a complete self-contained graph, with its inputs and outputs explicitly defined.
For example if your command line is of the form:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i infile -vf scale=640:360 outfile
</pre></td></tr></table>
<p>your <var>GRAPH_DESCRIPTION</var> string will need to be of the form:
</p><table><tr><td>&nbsp;</td><td><pre class="example">nullsrc,scale=640:360,nullsink
</pre></td></tr></table>
<p>you may also need to set the <var>nullsrc</var> parameters and add a <var>format</var>
filter in order to simulate a specific input file.
</p>
<a name="Filtergraph-description"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Filtergraph-description">23. Filtergraph description</a></h1>
<p>A filtergraph is a directed graph of connected filters. It can contain
cycles, and there can be multiple links between a pair of
filters. Each link has one input pad on one side connecting it to one
filter from which it takes its input, and one output pad on the other
side connecting it to the one filter accepting its output.
</p>
<p>Each filter in a filtergraph is an instance of a filter class
registered in the application, which defines the features and the
number of input and output pads of the filter.
</p>
<p>A filter with no input pads is called a &quot;source&quot;, a filter with no
output pads is called a &quot;sink&quot;.
</p>
<p><a name="Filtergraph-syntax"></a>
</p><a name="Filtergraph-syntax-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Filtergraph-syntax-1">23.1 Filtergraph syntax</a></h2>
<p>A filtergraph can be represented using a textual representation, which is
recognized by the &lsquo;<samp>-filter</samp>&rsquo;/&lsquo;<samp>-vf</samp>&rsquo; and &lsquo;<samp>-filter_complex</samp>&rsquo;
options in <code>ffmpeg</code> and &lsquo;<samp>-vf</samp>&rsquo; in <code>ffplay</code>, and by the
<code>avfilter_graph_parse()</code>/<code>avfilter_graph_parse2()</code> function defined in
&lsquo;<tt>libavfilter/avfilter.h</tt>&rsquo;.
</p>
<p>A filterchain consists of a sequence of connected filters, each one
connected to the previous one in the sequence. A filterchain is
represented by a list of &quot;,&quot;-separated filter descriptions.
</p>
<p>A filtergraph consists of a sequence of filterchains. A sequence of
filterchains is represented by a list of &quot;;&quot;-separated filterchain
descriptions.
</p>
<p>A filter is represented by a string of the form:
[<var>in_link_1</var>]...[<var>in_link_N</var>]<var>filter_name</var>=<var>arguments</var>[<var>out_link_1</var>]...[<var>out_link_M</var>]
</p>
<p><var>filter_name</var> is the name of the filter class of which the
described filter is an instance of, and has to be the name of one of
the filter classes registered in the program.
The name of the filter class is optionally followed by a string
&quot;=<var>arguments</var>&quot;.
</p>
<p><var>arguments</var> is a string which contains the parameters used to
initialize the filter instance. It may have one of the following forms:
</p><ul>
<li>
A &rsquo;:&rsquo;-separated list of <var>key=value</var> pairs.
</li><li>
A &rsquo;:&rsquo;-separated list of <var>value</var>. In this case, the keys are assumed to be
the option names in the order they are declared. E.g. the <code>fade</code> filter
declares three options in this order &ndash; &lsquo;<samp>type</samp>&rsquo;, &lsquo;<samp>start_frame</samp>&rsquo; and
&lsquo;<samp>nb_frames</samp>&rsquo;. Then the parameter list <var>in:0:30</var> means that the value
<var>in</var> is assigned to the option &lsquo;<samp>type</samp>&rsquo;, <var>0</var> to
&lsquo;<samp>start_frame</samp>&rsquo; and <var>30</var> to &lsquo;<samp>nb_frames</samp>&rsquo;.
</li><li>
A &rsquo;:&rsquo;-separated list of mixed direct <var>value</var> and long <var>key=value</var>
pairs. The direct <var>value</var> must precede the <var>key=value</var> pairs, and
follow the same constraints order of the previous point. The following
<var>key=value</var> pairs can be set in any preferred order.
</li></ul>
<p>If the option value itself is a list of items (e.g. the <code>format</code> filter
takes a list of pixel formats), the items in the list are usually separated by
&rsquo;|&rsquo;.
</p>
<p>The list of arguments can be quoted using the character &quot;&rsquo;&quot; as initial
and ending mark, and the character &rsquo;\&rsquo; for escaping the characters
within the quoted text; otherwise the argument string is considered
terminated when the next special character (belonging to the set
&quot;[]=;,&quot;) is encountered.
</p>
<p>The name and arguments of the filter are optionally preceded and
followed by a list of link labels.
A link label allows one to name a link and associate it to a filter output
or input pad. The preceding labels <var>in_link_1</var>
... <var>in_link_N</var>, are associated to the filter input pads,
the following labels <var>out_link_1</var> ... <var>out_link_M</var>, are
associated to the output pads.
</p>
<p>When two link labels with the same name are found in the
filtergraph, a link between the corresponding input and output pad is
created.
</p>
<p>If an output pad is not labelled, it is linked by default to the first
unlabelled input pad of the next filter in the filterchain.
For example in the filterchain:
</p><table><tr><td>&nbsp;</td><td><pre class="example">nullsrc, split[L1], [L2]overlay, nullsink
</pre></td></tr></table>
<p>the split filter instance has two output pads, and the overlay filter
instance two input pads. The first output pad of split is labelled
&quot;L1&quot;, the first input pad of overlay is labelled &quot;L2&quot;, and the second
output pad of split is linked to the second input pad of overlay,
which are both unlabelled.
</p>
<p>In a complete filterchain all the unlabelled filter input and output
pads must be connected. A filtergraph is considered valid if all the
filter input and output pads of all the filterchains are connected.
</p>
<p>Libavfilter will automatically insert <a href="#scale">scale</a> filters where format
conversion is required. It is possible to specify swscale flags
for those automatically inserted scalers by prepending
<code>sws_flags=<var>flags</var>;</code>
to the filtergraph description.
</p>
<p>Follows a BNF description for the filtergraph syntax:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>NAME</var> ::= sequence of alphanumeric characters and '_'
<var>LINKLABEL</var> ::= &quot;[&quot; <var>NAME</var> &quot;]&quot;
<var>LINKLABELS</var> ::= <var>LINKLABEL</var> [<var>LINKLABELS</var>]
<var>FILTER_ARGUMENTS</var> ::= sequence of chars (eventually quoted)
<var>FILTER</var> ::= [<var>LINKLABELS</var>] <var>NAME</var> [&quot;=&quot; <var>FILTER_ARGUMENTS</var>] [<var>LINKLABELS</var>]
<var>FILTERCHAIN</var> ::= <var>FILTER</var> [,<var>FILTERCHAIN</var>]
<var>FILTERGRAPH</var> ::= [sws_flags=<var>flags</var>;] <var>FILTERCHAIN</var> [;<var>FILTERGRAPH</var>]
</pre></td></tr></table>
<a name="Notes-on-filtergraph-escaping"></a>
<h2 class="section"><a href="ffplay-all.html#toc-Notes-on-filtergraph-escaping">23.2 Notes on filtergraph escaping</a></h2>
<p>Filtergraph description composition entails several levels of
escaping. See <a href="ffmpeg-utils.html#quoting_005fand_005fescaping">(ffmpeg-utils)quoting_and_escaping</a> for more
information about the employed escaping procedure.
</p>
<p>A first level escaping affects the content of each filter option
value, which may contain the special character <code>:</code> used to
separate values, or one of the escaping characters <code>\'</code>.
</p>
<p>A second level escaping affects the whole filter description, which
may contain the escaping characters <code>\'</code> or the special
characters <code>[],;</code> used by the filtergraph description.
</p>
<p>Finally, when you specify a filtergraph on a shell commandline, you
need to perform a third level escaping for the shell special
characters contained within it.
</p>
<p>For example, consider the following string to be embedded in
the <a href="#drawtext">drawtext</a> filter description &lsquo;<samp>text</samp>&rsquo; value:
</p><table><tr><td>&nbsp;</td><td><pre class="example">this is a 'string': may contain one, or more, special characters
</pre></td></tr></table>
<p>This string contains the <code>'</code> special escaping character, and the
<code>:</code> special character, so it needs to be escaped in this way:
</p><table><tr><td>&nbsp;</td><td><pre class="example">text=this is a \'string\'\: may contain one, or more, special characters
</pre></td></tr></table>
<p>A second level of escaping is required when embedding the filter
description in a filtergraph description, in order to escape all the
filtergraph special characters. Thus the example above becomes:
</p><table><tr><td>&nbsp;</td><td><pre class="example">drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
</pre></td></tr></table>
<p>(note that in addition to the <code>\'</code> escaping special characters,
also <code>,</code> needs to be escaped).
</p>
<p>Finally an additional level of escaping is needed when writing the
filtergraph description in a shell command, which depends on the
escaping rules of the adopted shell. For example, assuming that
<code>\</code> is special and needs to be escaped with another <code>\</code>, the
previous string will finally result in:
</p><table><tr><td>&nbsp;</td><td><pre class="example">-vf &quot;drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters&quot;
</pre></td></tr></table>
<a name="Timeline-editing"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Timeline-editing">24. Timeline editing</a></h1>
<p>Some filters support a generic &lsquo;<samp>enable</samp>&rsquo; option. For the filters
supporting timeline editing, this option can be set to an expression which is
evaluated before sending a frame to the filter. If the evaluation is non-zero,
the filter will be enabled, otherwise the frame will be sent unchanged to the
next filter in the filtergraph.
</p>
<p>The expression accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>timestamp expressed in seconds, NAN if the input timestamp is unknown
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>sequential number of the input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>the position in the file of the input frame, NAN if unknown
</p></dd>
</dl>
<p>Additionally, these filters support an &lsquo;<samp>enable</samp>&rsquo; command that can be used
to re-define the expression.
</p>
<p>Like any other filtering option, the &lsquo;<samp>enable</samp>&rsquo; option follows the same
rules.
</p>
<p>For example, to enable a blur filter (<a href="#smartblur">smartblur</a>) from 10 seconds to 3
minutes, and a <a href="#curves">curves</a> filter starting at 3 seconds:
</p><table><tr><td>&nbsp;</td><td><pre class="example">smartblur = enable='between(t,10,3*60)',
curves = enable='gte(t,3)' : preset=cross_process
</pre></td></tr></table>
<a name="Audio-Filters"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Audio-Filters">25. Audio Filters</a></h1>
<p>When you configure your FFmpeg build, you can disable any of the
existing filters using <code>--disable-filters</code>.
The configure output will show the audio filters included in your
build.
</p>
<p>Below is a description of the currently available audio filters.
</p>
<a name="aconvert"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aconvert">25.1 aconvert</a></h2>
<p>Convert the input audio format to the specified formats.
</p>
<p><em>This filter is deprecated. Use <a href="#aformat">aformat</a> instead.</em>
</p>
<p>The filter accepts a string of the form:
&quot;<var>sample_format</var>:<var>channel_layout</var>&quot;.
</p>
<p><var>sample_format</var> specifies the sample format, and can be a string or the
corresponding numeric value defined in &lsquo;<tt>libavutil/samplefmt.h</tt>&rsquo;. Use &rsquo;p&rsquo;
suffix for a planar sample format.
</p>
<p><var>channel_layout</var> specifies the channel layout, and can be a string
or the corresponding number value defined in &lsquo;<tt>libavutil/channel_layout.h</tt>&rsquo;.
</p>
<p>The special parameter &quot;auto&quot;, signifies that the filter will
automatically select the output format depending on the output filter.
</p>
<a name="Examples-66"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-66">25.1.1 Examples</a></h3>
<ul>
<li>
Convert input to float, planar, stereo:
<table><tr><td>&nbsp;</td><td><pre class="example">aconvert=fltp:stereo
</pre></td></tr></table>
</li><li>
Convert input to unsigned 8-bit, automatically select out channel layout:
<table><tr><td>&nbsp;</td><td><pre class="example">aconvert=u8:auto
</pre></td></tr></table>
</li></ul>
<a name="adelay"></a>
<h2 class="section"><a href="ffplay-all.html#toc-adelay">25.2 adelay</a></h2>
<p>Delay one or more audio channels.
</p>
<p>Samples in delayed channel are filled with silence.
</p>
<p>The filter accepts the following option:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>delays</samp>&rsquo;</dt>
<dd><p>Set list of delays in milliseconds for each channel separated by &rsquo;|&rsquo;.
At least one delay greater than 0 should be provided.
Unused delays will be silently ignored. If number of given delays is
smaller than number of channels all remaining channels will not be delayed.
</p></dd>
</dl>
<a name="Examples-13"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-13">25.2.1 Examples</a></h3>
<ul>
<li>
Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
the second channel (and any other channels that may be present) unchanged.
<table><tr><td>&nbsp;</td><td><pre class="example">adelay=1500|0|500
</pre></td></tr></table>
</li></ul>
<a name="aecho"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aecho">25.3 aecho</a></h2>
<p>Apply echoing to the input audio.
</p>
<p>Echoes are reflected sound and can occur naturally amongst mountains
(and sometimes large buildings) when talking or shouting; digital echo
effects emulate this behaviour and are often used to help fill out the
sound of a single instrument or vocal. The time difference between the
original signal and the reflection is the <code>delay</code>, and the
loudness of the reflected signal is the <code>decay</code>.
Multiple echoes can have different delays and decays.
</p>
<p>A description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>in_gain</samp>&rsquo;</dt>
<dd><p>Set input gain of reflected signal. Default is <code>0.6</code>.
</p>
</dd>
<dt> &lsquo;<samp>out_gain</samp>&rsquo;</dt>
<dd><p>Set output gain of reflected signal. Default is <code>0.3</code>.
</p>
</dd>
<dt> &lsquo;<samp>delays</samp>&rsquo;</dt>
<dd><p>Set list of time intervals in milliseconds between original signal and reflections
separated by &rsquo;|&rsquo;. Allowed range for each <code>delay</code> is <code>(0 - 90000.0]</code>.
Default is <code>1000</code>.
</p>
</dd>
<dt> &lsquo;<samp>decays</samp>&rsquo;</dt>
<dd><p>Set list of loudnesses of reflected signals separated by &rsquo;|&rsquo;.
Allowed range for each <code>decay</code> is <code>(0 - 1.0]</code>.
Default is <code>0.5</code>.
</p></dd>
</dl>
<a name="Examples-67"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-67">25.3.1 Examples</a></h3>
<ul>
<li>
Make it sound as if there are twice as many instruments as are actually playing:
<table><tr><td>&nbsp;</td><td><pre class="example">aecho=0.8:0.88:60:0.4
</pre></td></tr></table>
</li><li>
If delay is very short, then it sound like a (metallic) robot playing music:
<table><tr><td>&nbsp;</td><td><pre class="example">aecho=0.8:0.88:6:0.4
</pre></td></tr></table>
</li><li>
A longer delay will sound like an open air concert in the mountains:
<table><tr><td>&nbsp;</td><td><pre class="example">aecho=0.8:0.9:1000:0.3
</pre></td></tr></table>
</li><li>
Same as above but with one more mountain:
<table><tr><td>&nbsp;</td><td><pre class="example">aecho=0.8:0.9:1000|1800:0.3|0.25
</pre></td></tr></table>
</li></ul>
<a name="aeval"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aeval">25.4 aeval</a></h2>
<p>Modify an audio signal according to the specified expressions.
</p>
<p>This filter accepts one or more expressions (one for each channel),
which are evaluated and used to modify a corresponding audio signal.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>exprs</samp>&rsquo;</dt>
<dd><p>Set the &rsquo;|&rsquo;-separated expressions list for each separate channel. If
the number of input channels is greater than the number of
expressions, the last specified expression is used for the remaining
output channels.
</p>
</dd>
<dt> &lsquo;<samp>channel_layout, c</samp>&rsquo;</dt>
<dd><p>Set output channel layout. If not specified, the channel layout is
specified by the number of expressions. If set to &lsquo;<samp>same</samp>&rsquo;, it will
use by default the same input channel layout.
</p></dd>
</dl>
<p>Each expression in <var>exprs</var> can contain the following constants and functions:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>ch</samp>&rsquo;</dt>
<dd><p>channel number of the current expression
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>number of the evaluated sample, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>sample rate
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>time of the evaluated sample expressed in seconds
</p>
</dd>
<dt> &lsquo;<samp>nb_in_channels</samp>&rsquo;</dt>
<dt> &lsquo;<samp>nb_out_channels</samp>&rsquo;</dt>
<dd><p>input and output number of channels
</p>
</dd>
<dt> &lsquo;<samp>val(CH)</samp>&rsquo;</dt>
<dd><p>the value of input channel with number <var>CH</var>
</p></dd>
</dl>
<p>Note: this filter is slow. For faster processing you should use a
dedicated filter.
</p>
<a name="Examples-77"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-77">25.4.1 Examples</a></h3>
<ul>
<li>
Half volume:
<table><tr><td>&nbsp;</td><td><pre class="example">aeval=val(ch)/2:c=same
</pre></td></tr></table>
</li><li>
Invert phase of the second channel:
<table><tr><td>&nbsp;</td><td><pre class="example">eval=val(0)|-val(1)
</pre></td></tr></table>
</li></ul>
<a name="afade"></a>
<h2 class="section"><a href="ffplay-all.html#toc-afade">25.5 afade</a></h2>
<p>Apply fade-in/out effect to input audio.
</p>
<p>A description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>type, t</samp>&rsquo;</dt>
<dd><p>Specify the effect type, can be either <code>in</code> for fade-in, or
<code>out</code> for a fade-out effect. Default is <code>in</code>.
</p>
</dd>
<dt> &lsquo;<samp>start_sample, ss</samp>&rsquo;</dt>
<dd><p>Specify the number of the start sample for starting to apply the fade
effect. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>nb_samples, ns</samp>&rsquo;</dt>
<dd><p>Specify the number of samples for which the fade effect has to last. At
the end of the fade-in effect the output audio will have the same
volume as the input audio, at the end of the fade-out transition
the output audio will be silence. Default is 44100.
</p>
</dd>
<dt> &lsquo;<samp>start_time, st</samp>&rsquo;</dt>
<dd><p>Specify time for starting to apply the fade effect. Default is 0.
The accepted syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[-]HH[:MM[:SS[.m...]]]
[-]S+[.m...]
</pre></td></tr></table>
<p>See also the function <code>av_parse_time()</code>.
If set this option is used instead of <var>start_sample</var> one.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Specify the duration for which the fade effect has to last. Default is 0.
The accepted syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[-]HH[:MM[:SS[.m...]]]
[-]S+[.m...]
</pre></td></tr></table>
<p>See also the function <code>av_parse_time()</code>.
At the end of the fade-in effect the output audio will have the same
volume as the input audio, at the end of the fade-out transition
the output audio will be silence.
If set this option is used instead of <var>nb_samples</var> one.
</p>
</dd>
<dt> &lsquo;<samp>curve</samp>&rsquo;</dt>
<dd><p>Set curve for fade transition.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>tri</samp>&rsquo;</dt>
<dd><p>select triangular, linear slope (default)
</p></dd>
<dt> &lsquo;<samp>qsin</samp>&rsquo;</dt>
<dd><p>select quarter of sine wave
</p></dd>
<dt> &lsquo;<samp>hsin</samp>&rsquo;</dt>
<dd><p>select half of sine wave
</p></dd>
<dt> &lsquo;<samp>esin</samp>&rsquo;</dt>
<dd><p>select exponential sine wave
</p></dd>
<dt> &lsquo;<samp>log</samp>&rsquo;</dt>
<dd><p>select logarithmic
</p></dd>
<dt> &lsquo;<samp>par</samp>&rsquo;</dt>
<dd><p>select inverted parabola
</p></dd>
<dt> &lsquo;<samp>qua</samp>&rsquo;</dt>
<dd><p>select quadratic
</p></dd>
<dt> &lsquo;<samp>cub</samp>&rsquo;</dt>
<dd><p>select cubic
</p></dd>
<dt> &lsquo;<samp>squ</samp>&rsquo;</dt>
<dd><p>select square root
</p></dd>
<dt> &lsquo;<samp>cbr</samp>&rsquo;</dt>
<dd><p>select cubic root
</p></dd>
</dl>
</dd>
</dl>
<a name="Examples-33"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-33">25.5.1 Examples</a></h3>
<ul>
<li>
Fade in first 15 seconds of audio:
<table><tr><td>&nbsp;</td><td><pre class="example">afade=t=in:ss=0:d=15
</pre></td></tr></table>
</li><li>
Fade out last 25 seconds of a 900 seconds audio:
<table><tr><td>&nbsp;</td><td><pre class="example">afade=t=out:st=875:d=25
</pre></td></tr></table>
</li></ul>
<p><a name="aformat"></a>
</p><a name="aformat-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aformat-1">25.6 aformat</a></h2>
<p>Set output format constraints for the input audio. The framework will
negotiate the most appropriate format to minimize conversions.
</p>
<p>The filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>sample_fmts</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of requested sample formats.
</p>
</dd>
<dt> &lsquo;<samp>sample_rates</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of requested sample rates.
</p>
</dd>
<dt> &lsquo;<samp>channel_layouts</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of requested channel layouts.
</p>
<p>See <a href="ffmpeg-utils.html#channel-layout-syntax">(ffmpeg-utils)channel layout syntax</a>
for the required syntax.
</p></dd>
</dl>
<p>If a parameter is omitted, all values are allowed.
</p>
<p>For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
</p><table><tr><td>&nbsp;</td><td><pre class="example">aformat=sample_fmts=u8|s16:channel_layouts=stereo
</pre></td></tr></table>
<a name="allpass"></a>
<h2 class="section"><a href="ffplay-all.html#toc-allpass">25.7 allpass</a></h2>
<p>Apply a two-pole all-pass filter with central frequency (in Hz)
<var>frequency</var>, and filter-width <var>width</var>.
An all-pass filter changes the audio&rsquo;s frequency to phase relationship
without changing its frequency to amplitude relationship.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set frequency in Hz.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Specify the band-width of a filter in width_type units.
</p></dd>
</dl>
<a name="amerge"></a>
<h2 class="section"><a href="ffplay-all.html#toc-amerge">25.8 amerge</a></h2>
<p>Merge two or more audio streams into a single multi-channel stream.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>inputs</samp>&rsquo;</dt>
<dd><p>Set the number of inputs. Default is 2.
</p>
</dd>
</dl>
<p>If the channel layouts of the inputs are disjoint, and therefore compatible,
the channel layout of the output will be set accordingly and the channels
will be reordered as necessary. If the channel layouts of the inputs are not
disjoint, the output will have all the channels of the first input then all
the channels of the second input, in that order, and the channel layout of
the output will be the default value corresponding to the total number of
channels.
</p>
<p>For example, if the first input is in 2.1 (FL+FR+LF) and the second input
is FC+BL+BR, then the output will be in 5.1, with the channels in the
following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
first input, b1 is the first channel of the second input).
</p>
<p>On the other hand, if both input are in stereo, the output channels will be
in the default order: a1, a2, b1, b2, and the channel layout will be
arbitrarily set to 4.0, which may or may not be the expected value.
</p>
<p>All inputs must have the same sample rate, and format.
</p>
<p>If inputs do not have the same duration, the output will stop with the
shortest.
</p>
<a name="Examples-19"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-19">25.8.1 Examples</a></h3>
<ul>
<li>
Merge two mono files into a stereo stream:
<table><tr><td>&nbsp;</td><td><pre class="example">amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
</pre></td></tr></table>
</li><li>
Multiple merges assuming 1 video stream and 6 audio streams in &lsquo;<tt>input.mkv</tt>&rsquo;:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i input.mkv -filter_complex &quot;[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6&quot; -c:a pcm_s16le output.mkv
</pre></td></tr></table>
</li></ul>
<a name="amix"></a>
<h2 class="section"><a href="ffplay-all.html#toc-amix">25.9 amix</a></h2>
<p>Mixes multiple audio inputs into a single output.
</p>
<p>For example
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
</pre></td></tr></table>
<p>will mix 3 input audio streams to a single output with the same duration as the
first input and a dropout transition time of 3 seconds.
</p>
<p>The filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>inputs</samp>&rsquo;</dt>
<dd><p>Number of inputs. If unspecified, it defaults to 2.
</p>
</dd>
<dt> &lsquo;<samp>duration</samp>&rsquo;</dt>
<dd><p>How to determine the end-of-stream.
</p><dl compact="compact">
<dt> &lsquo;<samp>longest</samp>&rsquo;</dt>
<dd><p>Duration of longest input. (default)
</p>
</dd>
<dt> &lsquo;<samp>shortest</samp>&rsquo;</dt>
<dd><p>Duration of shortest input.
</p>
</dd>
<dt> &lsquo;<samp>first</samp>&rsquo;</dt>
<dd><p>Duration of first input.
</p>
</dd>
</dl>
</dd>
<dt> &lsquo;<samp>dropout_transition</samp>&rsquo;</dt>
<dd><p>Transition time, in seconds, for volume renormalization when an input
stream ends. The default value is 2 seconds.
</p>
</dd>
</dl>
<a name="anull"></a>
<h2 class="section"><a href="ffplay-all.html#toc-anull">25.10 anull</a></h2>
<p>Pass the audio source unchanged to the output.
</p>
<a name="apad"></a>
<h2 class="section"><a href="ffplay-all.html#toc-apad">25.11 apad</a></h2>
<p>Pad the end of a audio stream with silence, this can be used together with
-shortest to extend audio streams to the same length as the video stream.
</p>
<a name="aphaser"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aphaser">25.12 aphaser</a></h2>
<p>Add a phasing effect to the input audio.
</p>
<p>A phaser filter creates series of peaks and troughs in the frequency spectrum.
The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
</p>
<p>A description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>in_gain</samp>&rsquo;</dt>
<dd><p>Set input gain. Default is 0.4.
</p>
</dd>
<dt> &lsquo;<samp>out_gain</samp>&rsquo;</dt>
<dd><p>Set output gain. Default is 0.74
</p>
</dd>
<dt> &lsquo;<samp>delay</samp>&rsquo;</dt>
<dd><p>Set delay in milliseconds. Default is 3.0.
</p>
</dd>
<dt> &lsquo;<samp>decay</samp>&rsquo;</dt>
<dd><p>Set decay. Default is 0.4.
</p>
</dd>
<dt> &lsquo;<samp>speed</samp>&rsquo;</dt>
<dd><p>Set modulation speed in Hz. Default is 0.5.
</p>
</dd>
<dt> &lsquo;<samp>type</samp>&rsquo;</dt>
<dd><p>Set modulation type. Default is triangular.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>triangular, t</samp>&rsquo;</dt>
<dt> &lsquo;<samp>sinusoidal, s</samp>&rsquo;</dt>
</dl>
</dd>
</dl>
<p><a name="aresample"></a>
</p><a name="aresample-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aresample-1">25.13 aresample</a></h2>
<p>Resample the input audio to the specified parameters, using the
libswresample library. If none are specified then the filter will
automatically convert between its input and output.
</p>
<p>This filter is also able to stretch/squeeze the audio data to make it match
the timestamps or to inject silence / cut out audio to make it match the
timestamps, do a combination of both or do neither.
</p>
<p>The filter accepts the syntax
[<var>sample_rate</var>:]<var>resampler_options</var>, where <var>sample_rate</var>
expresses a sample rate and <var>resampler_options</var> is a list of
<var>key</var>=<var>value</var> pairs, separated by &quot;:&quot;. See the
ffmpeg-resampler manual for the complete list of supported options.
</p>
<a name="Examples-31"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-31">25.13.1 Examples</a></h3>
<ul>
<li>
Resample the input audio to 44100Hz:
<table><tr><td>&nbsp;</td><td><pre class="example">aresample=44100
</pre></td></tr></table>
</li><li>
Stretch/squeeze samples to the given timestamps, with a maximum of 1000
samples per second compensation:
<table><tr><td>&nbsp;</td><td><pre class="example">aresample=async=1000
</pre></td></tr></table>
</li></ul>
<a name="asetnsamples"></a>
<h2 class="section"><a href="ffplay-all.html#toc-asetnsamples">25.14 asetnsamples</a></h2>
<p>Set the number of samples per each output audio frame.
</p>
<p>The last output packet may contain a different number of samples, as
the filter will flush all the remaining samples when the input audio
signal its end.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>nb_out_samples, n</samp>&rsquo;</dt>
<dd><p>Set the number of frames per each output audio frame. The number is
intended as the number of samples <em>per each channel</em>.
Default value is 1024.
</p>
</dd>
<dt> &lsquo;<samp>pad, p</samp>&rsquo;</dt>
<dd><p>If set to 1, the filter will pad the last audio frame with zeroes, so
that the last frame will contain the same number of samples as the
previous ones. Default value is 1.
</p></dd>
</dl>
<p>For example, to set the number of per-frame samples to 1234 and
disable padding for the last frame, use:
</p><table><tr><td>&nbsp;</td><td><pre class="example">asetnsamples=n=1234:p=0
</pre></td></tr></table>
<a name="asetrate"></a>
<h2 class="section"><a href="ffplay-all.html#toc-asetrate">25.15 asetrate</a></h2>
<p>Set the sample rate without altering the PCM data.
This will result in a change of speed and pitch.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>sample_rate, r</samp>&rsquo;</dt>
<dd><p>Set the output sample rate. Default is 44100 Hz.
</p></dd>
</dl>
<a name="ashowinfo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ashowinfo">25.16 ashowinfo</a></h2>
<p>Show a line containing various information for each input audio frame.
The input audio is not modified.
</p>
<p>The shown line contains a sequence of key/value pairs of the form
<var>key</var>:<var>value</var>.
</p>
<p>A description of each shown parameter follows:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>sequential number of the input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dd><p>Presentation timestamp of the input frame, in time base units; the time base
depends on the filter input pad, and is usually 1/<var>sample_rate</var>.
</p>
</dd>
<dt> &lsquo;<samp>pts_time</samp>&rsquo;</dt>
<dd><p>presentation timestamp of the input frame in seconds
</p>
</dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>position of the frame in the input stream, -1 if this information in
unavailable and/or meaningless (for example in case of synthetic audio)
</p>
</dd>
<dt> &lsquo;<samp>fmt</samp>&rsquo;</dt>
<dd><p>sample format
</p>
</dd>
<dt> &lsquo;<samp>chlayout</samp>&rsquo;</dt>
<dd><p>channel layout
</p>
</dd>
<dt> &lsquo;<samp>rate</samp>&rsquo;</dt>
<dd><p>sample rate for the audio frame
</p>
</dd>
<dt> &lsquo;<samp>nb_samples</samp>&rsquo;</dt>
<dd><p>number of samples (per channel) in the frame
</p>
</dd>
<dt> &lsquo;<samp>checksum</samp>&rsquo;</dt>
<dd><p>Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
the data is treated as if all the planes were concatenated.
</p>
</dd>
<dt> &lsquo;<samp>plane_checksums</samp>&rsquo;</dt>
<dd><p>A list of Adler-32 checksums for each data plane.
</p></dd>
</dl>
<a name="astats"></a>
<h2 class="section"><a href="ffplay-all.html#toc-astats">25.17 astats</a></h2>
<p>Display time domain statistical information about the audio channels.
Statistics are calculated and displayed for each audio channel and,
where applicable, an overall figure is also given.
</p>
<p>The filter accepts the following option:
</p><dl compact="compact">
<dt> &lsquo;<samp>length</samp>&rsquo;</dt>
<dd><p>Short window length in seconds, used for peak and trough RMS measurement.
Default is <code>0.05</code> (50 miliseconds). Allowed range is <code>[0.1 - 10]</code>.
</p></dd>
</dl>
<p>A description of each shown parameter follows:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>DC offset</samp>&rsquo;</dt>
<dd><p>Mean amplitude displacement from zero.
</p>
</dd>
<dt> &lsquo;<samp>Min level</samp>&rsquo;</dt>
<dd><p>Minimal sample level.
</p>
</dd>
<dt> &lsquo;<samp>Max level</samp>&rsquo;</dt>
<dd><p>Maximal sample level.
</p>
</dd>
<dt> &lsquo;<samp>Peak level dB</samp>&rsquo;</dt>
<dt> &lsquo;<samp>RMS level dB</samp>&rsquo;</dt>
<dd><p>Standard peak and RMS level measured in dBFS.
</p>
</dd>
<dt> &lsquo;<samp>RMS peak dB</samp>&rsquo;</dt>
<dt> &lsquo;<samp>RMS trough dB</samp>&rsquo;</dt>
<dd><p>Peak and trough values for RMS level measured over a short window.
</p>
</dd>
<dt> &lsquo;<samp>Crest factor</samp>&rsquo;</dt>
<dd><p>Standard ratio of peak to RMS level (note: not in dB).
</p>
</dd>
<dt> &lsquo;<samp>Flat factor</samp>&rsquo;</dt>
<dd><p>Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
(i.e. either <var>Min level</var> or <var>Max level</var>).
</p>
</dd>
<dt> &lsquo;<samp>Peak count</samp>&rsquo;</dt>
<dd><p>Number of occasions (not the number of samples) that the signal attained either
<var>Min level</var> or <var>Max level</var>.
</p></dd>
</dl>
<a name="astreamsync"></a>
<h2 class="section"><a href="ffplay-all.html#toc-astreamsync">25.18 astreamsync</a></h2>
<p>Forward two audio streams and control the order the buffers are forwarded.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>expr, e</samp>&rsquo;</dt>
<dd><p>Set the expression deciding which stream should be
forwarded next: if the result is negative, the first stream is forwarded; if
the result is positive or zero, the second stream is forwarded. It can use
the following variables:
</p>
<dl compact="compact">
<dt> <var>b1 b2</var></dt>
<dd><p>number of buffers forwarded so far on each stream
</p></dd>
<dt> <var>s1 s2</var></dt>
<dd><p>number of samples forwarded so far on each stream
</p></dd>
<dt> <var>t1 t2</var></dt>
<dd><p>current timestamp of each stream
</p></dd>
</dl>
<p>The default value is <code>t1-t2</code>, which means to always forward the stream
that has a smaller timestamp.
</p></dd>
</dl>
<a name="Examples"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples">25.18.1 Examples</a></h3>
<p>Stress-test <code>amerge</code> by randomly sending buffers on the wrong
input, while avoiding too much of a desynchronization:
</p><table><tr><td>&nbsp;</td><td><pre class="example">amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
[a2] [b2] amerge
</pre></td></tr></table>
<a name="asyncts"></a>
<h2 class="section"><a href="ffplay-all.html#toc-asyncts">25.19 asyncts</a></h2>
<p>Synchronize audio data with timestamps by squeezing/stretching it and/or
dropping samples/adding silence when needed.
</p>
<p>This filter is not built by default, please use <a href="#aresample">aresample</a> to do squeezing/stretching.
</p>
<p>The filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>compensate</samp>&rsquo;</dt>
<dd><p>Enable stretching/squeezing the data to make it match the timestamps. Disabled
by default. When disabled, time gaps are covered with silence.
</p>
</dd>
<dt> &lsquo;<samp>min_delta</samp>&rsquo;</dt>
<dd><p>Minimum difference between timestamps and audio data (in seconds) to trigger
adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
this filter, try setting this parameter to 0.
</p>
</dd>
<dt> &lsquo;<samp>max_comp</samp>&rsquo;</dt>
<dd><p>Maximum compensation in samples per second. Relevant only with compensate=1.
Default value 500.
</p>
</dd>
<dt> &lsquo;<samp>first_pts</samp>&rsquo;</dt>
<dd><p>Assume the first pts should be this value. The time base is 1 / sample rate.
This allows for padding/trimming at the start of stream. By default, no
assumption is made about the first frame&rsquo;s expected pts, so no padding or
trimming is done. For example, this could be set to 0 to pad the beginning with
silence if an audio stream starts after the video stream or to trim any samples
with a negative pts due to encoder delay.
</p>
</dd>
</dl>
<a name="atempo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-atempo">25.20 atempo</a></h2>
<p>Adjust audio tempo.
</p>
<p>The filter accepts exactly one parameter, the audio tempo. If not
specified then the filter will assume nominal 1.0 tempo. Tempo must
be in the [0.5, 2.0] range.
</p>
<a name="Examples-18"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-18">25.20.1 Examples</a></h3>
<ul>
<li>
Slow down audio to 80% tempo:
<table><tr><td>&nbsp;</td><td><pre class="example">atempo=0.8
</pre></td></tr></table>
</li><li>
To speed up audio to 125% tempo:
<table><tr><td>&nbsp;</td><td><pre class="example">atempo=1.25
</pre></td></tr></table>
</li></ul>
<a name="atrim"></a>
<h2 class="section"><a href="ffplay-all.html#toc-atrim">25.21 atrim</a></h2>
<p>Trim the input so that the output contains one continuous subpart of the input.
</p>
<p>This filter accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>start</samp>&rsquo;</dt>
<dd><p>Specify time of the start of the kept section, i.e. the audio sample
with the timestamp <var>start</var> will be the first sample in the output.
</p>
</dd>
<dt> &lsquo;<samp>end</samp>&rsquo;</dt>
<dd><p>Specify time of the first audio sample that will be dropped, i.e. the
audio sample immediately preceding the one with the timestamp <var>end</var> will be
the last sample in the output.
</p>
</dd>
<dt> &lsquo;<samp>start_pts</samp>&rsquo;</dt>
<dd><p>Same as <var>start</var>, except this option sets the start timestamp in samples
instead of seconds.
</p>
</dd>
<dt> &lsquo;<samp>end_pts</samp>&rsquo;</dt>
<dd><p>Same as <var>end</var>, except this option sets the end timestamp in samples instead
of seconds.
</p>
</dd>
<dt> &lsquo;<samp>duration</samp>&rsquo;</dt>
<dd><p>Specify maximum duration of the output.
</p>
</dd>
<dt> &lsquo;<samp>start_sample</samp>&rsquo;</dt>
<dd><p>Number of the first sample that should be passed to output.
</p>
</dd>
<dt> &lsquo;<samp>end_sample</samp>&rsquo;</dt>
<dd><p>Number of the first sample that should be dropped.
</p></dd>
</dl>
<p>&lsquo;<samp>start</samp>&rsquo;, &lsquo;<samp>end</samp>&rsquo;, &lsquo;<samp>duration</samp>&rsquo; are expressed as time
duration specifications, check the &quot;Time duration&quot; section in the
ffmpeg-utils manual.
</p>
<p>Note that the first two sets of the start/end options and the &lsquo;<samp>duration</samp>&rsquo;
option look at the frame timestamp, while the _sample options simply count the
samples that pass through the filter. So start/end_pts and start/end_sample will
give different results when the timestamps are wrong, inexact or do not start at
zero. Also note that this filter does not modify the timestamps. If you wish
that the output timestamps start at zero, insert the asetpts filter after the
atrim filter.
</p>
<p>If multiple start or end options are set, this filter tries to be greedy and
keep all samples that match at least one of the specified constraints. To keep
only the part that matches all the constraints at once, chain multiple atrim
filters.
</p>
<p>The defaults are such that all the input is kept. So it is possible to set e.g.
just the end values to keep everything before the specified time.
</p>
<p>Examples:
</p><ul>
<li>
drop everything except the second minute of input
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -af atrim=60:120
</pre></td></tr></table>
</li><li>
keep only the first 1000 samples
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -af atrim=end_sample=1000
</pre></td></tr></table>
</li></ul>
<a name="bandpass"></a>
<h2 class="section"><a href="ffplay-all.html#toc-bandpass">25.22 bandpass</a></h2>
<p>Apply a two-pole Butterworth band-pass filter with central
frequency <var>frequency</var>, and (3dB-point) band-width width.
The <var>csg</var> option selects a constant skirt gain (peak gain = Q)
instead of the default: constant 0dB peak gain.
The filter roll off at 6dB per octave (20dB per decade).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set the filter&rsquo;s central frequency. Default is <code>3000</code>.
</p>
</dd>
<dt> &lsquo;<samp>csg</samp>&rsquo;</dt>
<dd><p>Constant skirt gain if set to 1. Defaults to 0.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Specify the band-width of a filter in width_type units.
</p></dd>
</dl>
<a name="bandreject"></a>
<h2 class="section"><a href="ffplay-all.html#toc-bandreject">25.23 bandreject</a></h2>
<p>Apply a two-pole Butterworth band-reject filter with central
frequency <var>frequency</var>, and (3dB-point) band-width <var>width</var>.
The filter roll off at 6dB per octave (20dB per decade).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set the filter&rsquo;s central frequency. Default is <code>3000</code>.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Specify the band-width of a filter in width_type units.
</p></dd>
</dl>
<a name="bass"></a>
<h2 class="section"><a href="ffplay-all.html#toc-bass">25.24 bass</a></h2>
<p>Boost or cut the bass (lower) frequencies of the audio using a two-pole
shelving filter with a response similar to that of a standard
hi-fi&rsquo;s tone-controls. This is also known as shelving equalisation (EQ).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>gain, g</samp>&rsquo;</dt>
<dd><p>Give the gain at 0 Hz. Its useful range is about -20
(for a large cut) to +20 (for a large boost).
Beware of clipping when using a positive gain.
</p>
</dd>
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set the filter&rsquo;s central frequency and so can be used
to extend or reduce the frequency range to be boosted or cut.
The default value is <code>100</code> Hz.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Determine how steep is the filter&rsquo;s shelf transition.
</p></dd>
</dl>
<a name="biquad"></a>
<h2 class="section"><a href="ffplay-all.html#toc-biquad">25.25 biquad</a></h2>
<p>Apply a biquad IIR filter with the given coefficients.
Where <var>b0</var>, <var>b1</var>, <var>b2</var> and <var>a0</var>, <var>a1</var>, <var>a2</var>
are the numerator and denominator coefficients respectively.
</p>
<a name="channelmap"></a>
<h2 class="section"><a href="ffplay-all.html#toc-channelmap">25.26 channelmap</a></h2>
<p>Remap input channels to new locations.
</p>
<p>This filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>channel_layout</samp>&rsquo;</dt>
<dd><p>Channel layout of the output stream.
</p>
</dd>
<dt> &lsquo;<samp>map</samp>&rsquo;</dt>
<dd><p>Map channels from input to output. The argument is a &rsquo;|&rsquo;-separated list of
mappings, each in the <code><var>in_channel</var>-<var>out_channel</var></code> or
<var>in_channel</var> form. <var>in_channel</var> can be either the name of the input
channel (e.g. FL for front left) or its index in the input channel layout.
<var>out_channel</var> is the name of the output channel or its index in the output
channel layout. If <var>out_channel</var> is not given then it is implicitly an
index, starting with zero and increasing by one for each mapping.
</p></dd>
</dl>
<p>If no mapping is present, the filter will implicitly map input channels to
output channels preserving index.
</p>
<p>For example, assuming a 5.1+downmix input MOV file
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
</pre></td></tr></table>
<p>will create an output WAV file tagged as stereo from the downmix channels of
the input.
</p>
<p>To fix a 5.1 WAV improperly encoded in AAC&rsquo;s native channel order
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
</pre></td></tr></table>
<a name="channelsplit"></a>
<h2 class="section"><a href="ffplay-all.html#toc-channelsplit">25.27 channelsplit</a></h2>
<p>Split each channel in input audio stream into a separate output stream.
</p>
<p>This filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>channel_layout</samp>&rsquo;</dt>
<dd><p>Channel layout of the input stream. Default is &quot;stereo&quot;.
</p></dd>
</dl>
<p>For example, assuming a stereo input MP3 file
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
</pre></td></tr></table>
<p>will create an output Matroska file with two audio streams, one containing only
the left channel and the other the right channel.
</p>
<p>To split a 5.1 WAV file into per-channel files
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.wav -filter_complex
'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
-map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
side_right.wav
</pre></td></tr></table>
<a name="compand"></a>
<h2 class="section"><a href="ffplay-all.html#toc-compand">25.28 compand</a></h2>
<p>Compress or expand audio dynamic range.
</p>
<p>A description of the accepted options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>attacks</samp>&rsquo;</dt>
<dt> &lsquo;<samp>decays</samp>&rsquo;</dt>
<dd><p>Set list of times in seconds for each channel over which the instantaneous level
of the input signal is averaged to determine its volume. <var>attacks</var> refers to
increase of volume and <var>decays</var> refers to decrease of volume. For most
situations, the attack time (response to the audio getting louder) should be
shorter than the decay time because the human ear is more sensitive to sudden
loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
a typical value for decay is 0.8 seconds.
</p>
</dd>
<dt> &lsquo;<samp>points</samp>&rsquo;</dt>
<dd><p>Set list of points for the transfer function, specified in dB relative to the
maximum possible signal amplitude. Each key points list must be defined using
the following syntax: <code>x0/y0|x1/y1|x2/y2|....</code> or
<code>x0/y0 x1/y1 x2/y2 ....</code>
</p>
<p>The input values must be in strictly increasing order but the transfer function
does not have to be monotonically rising. The point <code>0/0</code> is assumed but
may be overridden (by <code>0/out-dBn</code>). Typical values for the transfer
function are <code>-70/-70|-60/-20</code>.
</p>
</dd>
<dt> &lsquo;<samp>soft-knee</samp>&rsquo;</dt>
<dd><p>Set the curve radius in dB for all joints. Defaults to 0.01.
</p>
</dd>
<dt> &lsquo;<samp>gain</samp>&rsquo;</dt>
<dd><p>Set additional gain in dB to be applied at all points on the transfer function.
This allows easy adjustment of the overall gain. Defaults to 0.
</p>
</dd>
<dt> &lsquo;<samp>volume</samp>&rsquo;</dt>
<dd><p>Set initial volume in dB to be assumed for each channel when filtering starts.
This permits the user to supply a nominal level initially, so that, for
example, a very large gain is not applied to initial signal levels before the
companding has begun to operate. A typical value for audio which is initially
quiet is -90 dB. Defaults to 0.
</p>
</dd>
<dt> &lsquo;<samp>delay</samp>&rsquo;</dt>
<dd><p>Set delay in seconds. The input audio is analyzed immediately, but audio is
delayed before being fed to the volume adjuster. Specifying a delay
approximately equal to the attack/decay times allows the filter to effectively
operate in predictive rather than reactive mode. Defaults to 0.
</p>
</dd>
</dl>
<a name="Examples-51"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-51">25.28.1 Examples</a></h3>
<ul>
<li>
Make music with both quiet and loud passages suitable for listening in a noisy
environment:
<table><tr><td>&nbsp;</td><td><pre class="example">compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
</pre></td></tr></table>
</li><li>
Noise gate for when the noise is at a lower level than the signal:
<table><tr><td>&nbsp;</td><td><pre class="example">compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
</pre></td></tr></table>
</li><li>
Here is another noise gate, this time for when the noise is at a higher level
than the signal (making it, in some ways, similar to squelch):
<table><tr><td>&nbsp;</td><td><pre class="example">compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
</pre></td></tr></table>
</li></ul>
<a name="earwax"></a>
<h2 class="section"><a href="ffplay-all.html#toc-earwax">25.29 earwax</a></h2>
<p>Make audio easier to listen to on headphones.
</p>
<p>This filter adds &lsquo;cues&rsquo; to 44.1kHz stereo (i.e. audio CD format) audio
so that when listened to on headphones the stereo image is moved from
inside your head (standard for headphones) to outside and in front of
the listener (standard for speakers).
</p>
<p>Ported from SoX.
</p>
<a name="equalizer"></a>
<h2 class="section"><a href="ffplay-all.html#toc-equalizer">25.30 equalizer</a></h2>
<p>Apply a two-pole peaking equalisation (EQ) filter. With this
filter, the signal-level at and around a selected frequency can
be increased or decreased, whilst (unlike bandpass and bandreject
filters) that at all other frequencies is unchanged.
</p>
<p>In order to produce complex equalisation curves, this filter can
be given several times, each with a different central frequency.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set the filter&rsquo;s central frequency in Hz.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Specify the band-width of a filter in width_type units.
</p>
</dd>
<dt> &lsquo;<samp>gain, g</samp>&rsquo;</dt>
<dd><p>Set the required gain or attenuation in dB.
Beware of clipping when using a positive gain.
</p></dd>
</dl>
<a name="Examples-26"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-26">25.30.1 Examples</a></h3>
<ul>
<li>
Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
<table><tr><td>&nbsp;</td><td><pre class="example">equalizer=f=1000:width_type=h:width=200:g=-10
</pre></td></tr></table>
</li><li>
Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
<table><tr><td>&nbsp;</td><td><pre class="example">equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
</pre></td></tr></table>
</li></ul>
<a name="highpass"></a>
<h2 class="section"><a href="ffplay-all.html#toc-highpass">25.31 highpass</a></h2>
<p>Apply a high-pass filter with 3dB point frequency.
The filter can be either single-pole, or double-pole (the default).
The filter roll off at 6dB per pole per octave (20dB per pole per decade).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set frequency in Hz. Default is 3000.
</p>
</dd>
<dt> &lsquo;<samp>poles, p</samp>&rsquo;</dt>
<dd><p>Set number of poles. Default is 2.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Specify the band-width of a filter in width_type units.
Applies only to double-pole filter.
The default is 0.707q and gives a Butterworth response.
</p></dd>
</dl>
<a name="join"></a>
<h2 class="section"><a href="ffplay-all.html#toc-join">25.32 join</a></h2>
<p>Join multiple input streams into one multi-channel stream.
</p>
<p>The filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>inputs</samp>&rsquo;</dt>
<dd><p>Number of input streams. Defaults to 2.
</p>
</dd>
<dt> &lsquo;<samp>channel_layout</samp>&rsquo;</dt>
<dd><p>Desired output channel layout. Defaults to stereo.
</p>
</dd>
<dt> &lsquo;<samp>map</samp>&rsquo;</dt>
<dd><p>Map channels from inputs to output. The argument is a &rsquo;|&rsquo;-separated list of
mappings, each in the <code><var>input_idx</var>.<var>in_channel</var>-<var>out_channel</var></code>
form. <var>input_idx</var> is the 0-based index of the input stream. <var>in_channel</var>
can be either the name of the input channel (e.g. FL for front left) or its
index in the specified input stream. <var>out_channel</var> is the name of the output
channel.
</p></dd>
</dl>
<p>The filter will attempt to guess the mappings when those are not specified
explicitly. It does so by first trying to find an unused matching input channel
and if that fails it picks the first unused input channel.
</p>
<p>E.g. to join 3 inputs (with properly set channel layouts)
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
</pre></td></tr></table>
<p>To build a 5.1 output from 6 single-channel streams:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
out
</pre></td></tr></table>
<a name="ladspa"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ladspa">25.33 ladspa</a></h2>
<p>Load a LADSPA (Linux Audio Developer&rsquo;s Simple Plugin API) plugin.
</p>
<p>To enable compilation of this filter you need to configure FFmpeg with
<code>--enable-ladspa</code>.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>file, f</samp>&rsquo;</dt>
<dd><p>Specifies the name of LADSPA plugin library to load. If the environment
variable <code>LADSPA_PATH</code> is defined, the LADSPA plugin is searched in
each one of the directories specified by the colon separated list in
<code>LADSPA_PATH</code>, otherwise in the standard LADSPA paths, which are in
this order: &lsquo;<tt>HOME/.ladspa/lib/</tt>&rsquo;, &lsquo;<tt>/usr/local/lib/ladspa/</tt>&rsquo;,
&lsquo;<tt>/usr/lib/ladspa/</tt>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>plugin, p</samp>&rsquo;</dt>
<dd><p>Specifies the plugin within the library. Some libraries contain only
one plugin, but others contain many of them. If this is not set filter
will list all available plugins within the specified library.
</p>
</dd>
<dt> &lsquo;<samp>controls, c</samp>&rsquo;</dt>
<dd><p>Set the &rsquo;|&rsquo; separated list of controls which are zero or more floating point
values that determine the behavior of the loaded plugin (for example delay,
threshold or gain).
Controls need to be defined using the following syntax:
c0=<var>value0</var>|c1=<var>value1</var>|c2=<var>value2</var>|..., where
<var>valuei</var> is the value set on the <var>i</var>-th control.
If &lsquo;<samp>controls</samp>&rsquo; is set to <code>help</code>, all available controls and
their valid ranges are printed.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate, s</samp>&rsquo;</dt>
<dd><p>Specify the sample rate, default to 44100. Only used if plugin have
zero inputs.
</p>
</dd>
<dt> &lsquo;<samp>nb_samples, n</samp>&rsquo;</dt>
<dd><p>Set the number of samples per channel per each output frame, default
is 1024. Only used if plugin have zero inputs.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Set the minimum duration of the sourced audio. See the function
<code>av_parse_time()</code> for the accepted format, also check the &quot;Time duration&quot;
section in the ffmpeg-utils manual.
Note that the resulting duration may be greater than the specified duration,
as the generated audio is always cut at the end of a complete frame.
If not specified, or the expressed duration is negative, the audio is
supposed to be generated forever.
Only used if plugin have zero inputs.
</p>
</dd>
</dl>
<a name="Examples-59"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-59">25.33.1 Examples</a></h3>
<ul>
<li>
List all available plugins within amp (LADSPA example plugin) library:
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=file=amp
</pre></td></tr></table>
</li><li>
List all available controls and their valid ranges for <code>vcf_notch</code>
plugin from <code>VCF</code> library:
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=f=vcf:p=vcf_notch:c=help
</pre></td></tr></table>
</li><li>
Simulate low quality audio equipment using <code>Computer Music Toolkit</code> (CMT)
plugin library:
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
</pre></td></tr></table>
</li><li>
Add reverberation to the audio using TAP-plugins
(Tom&rsquo;s Audio Processing plugins):
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=file=tap_reverb:tap_reverb
</pre></td></tr></table>
</li><li>
Generate white noise, with 0.2 amplitude:
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=file=cmt:noise_source_white:c=c0=.2
</pre></td></tr></table>
</li><li>
Generate 20 bpm clicks using plugin <code>C* Click - Metronome</code> from the
<code>C* Audio Plugin Suite</code> (CAPS) library:
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=file=caps:Click:c=c1=20'
</pre></td></tr></table>
</li><li>
Apply <code>C* Eq10X2 - Stereo 10-band equaliser</code> effect:
<table><tr><td>&nbsp;</td><td><pre class="example">ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
</pre></td></tr></table>
</li></ul>
<a name="Commands"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands">25.33.2 Commands</a></h3>
<p>This filter supports the following commands:
</p><dl compact="compact">
<dt> &lsquo;<samp>cN</samp>&rsquo;</dt>
<dd><p>Modify the <var>N</var>-th control value.
</p>
<p>If the specified value is not valid, it is ignored and prior one is kept.
</p></dd>
</dl>
<a name="lowpass"></a>
<h2 class="section"><a href="ffplay-all.html#toc-lowpass">25.34 lowpass</a></h2>
<p>Apply a low-pass filter with 3dB point frequency.
The filter can be either single-pole or double-pole (the default).
The filter roll off at 6dB per pole per octave (20dB per pole per decade).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set frequency in Hz. Default is 500.
</p>
</dd>
<dt> &lsquo;<samp>poles, p</samp>&rsquo;</dt>
<dd><p>Set number of poles. Default is 2.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Specify the band-width of a filter in width_type units.
Applies only to double-pole filter.
The default is 0.707q and gives a Butterworth response.
</p></dd>
</dl>
<a name="pan"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pan">25.35 pan</a></h2>
<p>Mix channels with specific gain levels. The filter accepts the output
channel layout followed by a set of channels definitions.
</p>
<p>This filter is also designed to remap efficiently the channels of an audio
stream.
</p>
<p>The filter accepts parameters of the form:
&quot;<var>l</var>:<var>outdef</var>:<var>outdef</var>:...&quot;
</p>
<dl compact="compact">
<dt> &lsquo;<samp>l</samp>&rsquo;</dt>
<dd><p>output channel layout or number of channels
</p>
</dd>
<dt> &lsquo;<samp>outdef</samp>&rsquo;</dt>
<dd><p>output channel specification, of the form:
&quot;<var>out_name</var>=[<var>gain</var>*]<var>in_name</var>[+[<var>gain</var>*]<var>in_name</var>...]&quot;
</p>
</dd>
<dt> &lsquo;<samp>out_name</samp>&rsquo;</dt>
<dd><p>output channel to define, either a channel name (FL, FR, etc.) or a channel
number (c0, c1, etc.)
</p>
</dd>
<dt> &lsquo;<samp>gain</samp>&rsquo;</dt>
<dd><p>multiplicative coefficient for the channel, 1 leaving the volume unchanged
</p>
</dd>
<dt> &lsquo;<samp>in_name</samp>&rsquo;</dt>
<dd><p>input channel to use, see out_name for details; it is not possible to mix
named and numbered input channels
</p></dd>
</dl>
<p>If the &lsquo;=&rsquo; in a channel specification is replaced by &lsquo;&lt;&rsquo;, then the gains for
that specification will be renormalized so that the total is 1, thus
avoiding clipping noise.
</p>
<a name="Mixing-examples"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Mixing-examples">25.35.1 Mixing examples</a></h3>
<p>For example, if you want to down-mix from stereo to mono, but with a bigger
factor for the left channel:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pan=1:c0=0.9*c0+0.1*c1
</pre></td></tr></table>
<p>A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
7-channels surround:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pan=stereo: FL &lt; FL + 0.5*FC + 0.6*BL + 0.6*SL : FR &lt; FR + 0.5*FC + 0.6*BR + 0.6*SR
</pre></td></tr></table>
<p>Note that <code>ffmpeg</code> integrates a default down-mix (and up-mix) system
that should be preferred (see &quot;-ac&quot; option) unless you have very specific
needs.
</p>
<a name="Remapping-examples"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Remapping-examples">25.35.2 Remapping examples</a></h3>
<p>The channel remapping will be effective if, and only if:
</p>
<ul>
<li> gain coefficients are zeroes or ones,
</li><li> only one input per channel output,
</li></ul>
<p>If all these conditions are satisfied, the filter will notify the user (&quot;Pure
channel mapping detected&quot;), and use an optimized and lossless method to do the
remapping.
</p>
<p>For example, if you have a 5.1 source and want a stereo audio stream by
dropping the extra channels:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pan=&quot;stereo: c0=FL : c1=FR&quot;
</pre></td></tr></table>
<p>Given the same source, you can also switch front left and front right channels
and keep the input channel layout:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pan=&quot;5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5&quot;
</pre></td></tr></table>
<p>If the input is a stereo audio stream, you can mute the front left channel (and
still keep the stereo channel layout) with:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pan=&quot;stereo:c1=c1&quot;
</pre></td></tr></table>
<p>Still with a stereo audio stream input, you can copy the right channel in both
front left and right:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pan=&quot;stereo: c0=FR : c1=FR&quot;
</pre></td></tr></table>
<a name="replaygain"></a>
<h2 class="section"><a href="ffplay-all.html#toc-replaygain">25.36 replaygain</a></h2>
<p>ReplayGain scanner filter. This filter takes an audio stream as an input and
outputs it unchanged.
At end of filtering it displays <code>track_gain</code> and <code>track_peak</code>.
</p>
<a name="resample"></a>
<h2 class="section"><a href="ffplay-all.html#toc-resample">25.37 resample</a></h2>
<p>Convert the audio sample format, sample rate and channel layout. This filter is
not meant to be used directly.
</p>
<a name="silencedetect"></a>
<h2 class="section"><a href="ffplay-all.html#toc-silencedetect">25.38 silencedetect</a></h2>
<p>Detect silence in an audio stream.
</p>
<p>This filter logs a message when it detects that the input audio volume is less
or equal to a noise tolerance value for a duration greater or equal to the
minimum detected noise duration.
</p>
<p>The printed times and duration are expressed in seconds.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Set silence duration until notification (default is 2 seconds).
</p>
</dd>
<dt> &lsquo;<samp>noise, n</samp>&rsquo;</dt>
<dd><p>Set noise tolerance. Can be specified in dB (in case &quot;dB&quot; is appended to the
specified value) or amplitude ratio. Default is -60dB, or 0.001.
</p></dd>
</dl>
<a name="Examples-55"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-55">25.38.1 Examples</a></h3>
<ul>
<li>
Detect 5 seconds of silence with -50dB noise tolerance:
<table><tr><td>&nbsp;</td><td><pre class="example">silencedetect=n=-50dB:d=5
</pre></td></tr></table>
</li><li>
Complete example with <code>ffmpeg</code> to detect silence with 0.0001 noise
tolerance in &lsquo;<tt>silence.mp3</tt>&rsquo;:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
</pre></td></tr></table>
</li></ul>
<a name="treble"></a>
<h2 class="section"><a href="ffplay-all.html#toc-treble">25.39 treble</a></h2>
<p>Boost or cut treble (upper) frequencies of the audio using a two-pole
shelving filter with a response similar to that of a standard
hi-fi&rsquo;s tone-controls. This is also known as shelving equalisation (EQ).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>gain, g</samp>&rsquo;</dt>
<dd><p>Give the gain at whichever is the lower of ~22 kHz and the
Nyquist frequency. Its useful range is about -20 (for a large cut)
to +20 (for a large boost). Beware of clipping when using a positive gain.
</p>
</dd>
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set the filter&rsquo;s central frequency and so can be used
to extend or reduce the frequency range to be boosted or cut.
The default value is <code>3000</code> Hz.
</p>
</dd>
<dt> &lsquo;<samp>width_type</samp>&rsquo;</dt>
<dd><p>Set method to specify band-width of filter.
</p><dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Hz
</p></dd>
<dt> &lsquo;<samp>q</samp>&rsquo;</dt>
<dd><p>Q-Factor
</p></dd>
<dt> &lsquo;<samp>o</samp>&rsquo;</dt>
<dd><p>octave
</p></dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>slope
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dd><p>Determine how steep is the filter&rsquo;s shelf transition.
</p></dd>
</dl>
<a name="volume"></a>
<h2 class="section"><a href="ffplay-all.html#toc-volume">25.40 volume</a></h2>
<p>Adjust the input audio volume.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>volume</samp>&rsquo;</dt>
<dd><p>Set audio volume expression.
</p>
<p>Output values are clipped to the maximum value.
</p>
<p>The output audio volume is given by the relation:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>output_volume</var> = <var>volume</var> * <var>input_volume</var>
</pre></td></tr></table>
<p>Default value for <var>volume</var> is &quot;1.0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>precision</samp>&rsquo;</dt>
<dd><p>Set the mathematical precision.
</p>
<p>This determines which input sample formats will be allowed, which affects the
precision of the volume scaling.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>fixed</samp>&rsquo;</dt>
<dd><p>8-bit fixed-point; limits input sample format to U8, S16, and S32.
</p></dd>
<dt> &lsquo;<samp>float</samp>&rsquo;</dt>
<dd><p>32-bit floating-point; limits input sample format to FLT. (default)
</p></dd>
<dt> &lsquo;<samp>double</samp>&rsquo;</dt>
<dd><p>64-bit floating-point; limits input sample format to DBL.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>replaygain</samp>&rsquo;</dt>
<dd><p>Behaviour on encountering ReplayGain side data in input frames.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>drop</samp>&rsquo;</dt>
<dd><p>Remove ReplayGain side data, ignoring its contents (the default).
</p>
</dd>
<dt> &lsquo;<samp>ignore</samp>&rsquo;</dt>
<dd><p>Ignore ReplayGain side data, but leave it in the frame.
</p>
</dd>
<dt> &lsquo;<samp>track</samp>&rsquo;</dt>
<dd><p>Prefer track gain, if present.
</p>
</dd>
<dt> &lsquo;<samp>album</samp>&rsquo;</dt>
<dd><p>Prefer album gain, if present.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>replaygain_preamp</samp>&rsquo;</dt>
<dd><p>Pre-amplification gain in dB to apply to the selected replaygain gain.
</p>
<p>Default value for <var>replaygain_preamp</var> is 0.0.
</p>
</dd>
<dt> &lsquo;<samp>eval</samp>&rsquo;</dt>
<dd><p>Set when the volume expression is evaluated.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>once</samp>&rsquo;</dt>
<dd><p>only evaluate expression once during the filter initialization, or
when the &lsquo;<samp>volume</samp>&rsquo; command is sent
</p>
</dd>
<dt> &lsquo;<samp>frame</samp>&rsquo;</dt>
<dd><p>evaluate expression for each incoming frame
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>once</samp>&rsquo;.
</p></dd>
</dl>
<p>The volume expression can contain the following parameters.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>frame number (starting at zero)
</p></dd>
<dt> &lsquo;<samp>nb_channels</samp>&rsquo;</dt>
<dd><p>number of channels
</p></dd>
<dt> &lsquo;<samp>nb_consumed_samples</samp>&rsquo;</dt>
<dd><p>number of samples consumed by the filter
</p></dd>
<dt> &lsquo;<samp>nb_samples</samp>&rsquo;</dt>
<dd><p>number of samples in the current frame
</p></dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>original frame position in the file
</p></dd>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dd><p>frame PTS
</p></dd>
<dt> &lsquo;<samp>sample_rate</samp>&rsquo;</dt>
<dd><p>sample rate
</p></dd>
<dt> &lsquo;<samp>startpts</samp>&rsquo;</dt>
<dd><p>PTS at start of stream
</p></dd>
<dt> &lsquo;<samp>startt</samp>&rsquo;</dt>
<dd><p>time at start of stream
</p></dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>frame time
</p></dd>
<dt> &lsquo;<samp>tb</samp>&rsquo;</dt>
<dd><p>timestamp timebase
</p></dd>
<dt> &lsquo;<samp>volume</samp>&rsquo;</dt>
<dd><p>last set volume value
</p></dd>
</dl>
<p>Note that when &lsquo;<samp>eval</samp>&rsquo; is set to &lsquo;<samp>once</samp>&rsquo; only the
<var>sample_rate</var> and <var>tb</var> variables are available, all other
variables will evaluate to NAN.
</p>
<a name="Commands-4"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands-4">25.40.1 Commands</a></h3>
<p>This filter supports the following commands:
</p><dl compact="compact">
<dt> &lsquo;<samp>volume</samp>&rsquo;</dt>
<dd><p>Modify the volume expression.
The command accepts the same syntax of the corresponding option.
</p>
<p>If the specified expression is not valid, it is kept at its current
value.
</p></dd>
</dl>
<a name="Examples-30"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-30">25.40.2 Examples</a></h3>
<ul>
<li>
Halve the input audio volume:
<table><tr><td>&nbsp;</td><td><pre class="example">volume=volume=0.5
volume=volume=1/2
volume=volume=-6.0206dB
</pre></td></tr></table>
<p>In all the above example the named key for &lsquo;<samp>volume</samp>&rsquo; can be
omitted, for example like in:
</p><table><tr><td>&nbsp;</td><td><pre class="example">volume=0.5
</pre></td></tr></table>
</li><li>
Increase input audio power by 6 decibels using fixed-point precision:
<table><tr><td>&nbsp;</td><td><pre class="example">volume=volume=6dB:precision=fixed
</pre></td></tr></table>
</li><li>
Fade volume after time 10 with an annihilation period of 5 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
</pre></td></tr></table>
</li></ul>
<a name="volumedetect"></a>
<h2 class="section"><a href="ffplay-all.html#toc-volumedetect">25.41 volumedetect</a></h2>
<p>Detect the volume of the input video.
</p>
<p>The filter has no parameters. The input is not modified. Statistics about
the volume will be printed in the log when the input stream end is reached.
</p>
<p>In particular it will show the mean volume (root mean square), maximum
volume (on a per-sample basis), and the beginning of a histogram of the
registered volume values (from the maximum value to a cumulated 1/1000 of
the samples).
</p>
<p>All volumes are in decibels relative to the maximum PCM value.
</p>
<a name="Examples-10"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-10">25.41.1 Examples</a></h3>
<p>Here is an excerpt of the output:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[Parsed_volumedetect_0 &nbsp;0xa23120] mean_volume: -27 dB
[Parsed_volumedetect_0 &nbsp;0xa23120] max_volume: -4 dB
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_4db: 6
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_5db: 62
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_6db: 286
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_7db: 1042
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_8db: 2551
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_9db: 4609
[Parsed_volumedetect_0 &nbsp;0xa23120] histogram_10db: 8409
</pre></td></tr></table>
<p>It means that:
</p><ul>
<li>
The mean square energy is approximately -27 dB, or 10^-2.7.
</li><li>
The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
</li><li>
There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
</li></ul>
<p>In other words, raising the volume by +4 dB does not cause any clipping,
raising it by +5 dB causes clipping for 6 samples, etc.
</p>
<a name="Audio-Sources"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Audio-Sources">26. Audio Sources</a></h1>
<p>Below is a description of the currently available audio sources.
</p>
<a name="abuffer"></a>
<h2 class="section"><a href="ffplay-all.html#toc-abuffer">26.1 abuffer</a></h2>
<p>Buffer audio frames, and make them available to the filter chain.
</p>
<p>This source is mainly intended for a programmatic use, in particular
through the interface defined in &lsquo;<tt>libavfilter/asrc_abuffer.h</tt>&rsquo;.
</p>
<p>It accepts the following named parameters:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>time_base</samp>&rsquo;</dt>
<dd><p>Timebase which will be used for timestamps of submitted frames. It must be
either a floating-point number or in <var>numerator</var>/<var>denominator</var> form.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate</samp>&rsquo;</dt>
<dd><p>The sample rate of the incoming audio buffers.
</p>
</dd>
<dt> &lsquo;<samp>sample_fmt</samp>&rsquo;</dt>
<dd><p>The sample format of the incoming audio buffers.
Either a sample format name or its corresponging integer representation from
the enum AVSampleFormat in &lsquo;<tt>libavutil/samplefmt.h</tt>&rsquo;
</p>
</dd>
<dt> &lsquo;<samp>channel_layout</samp>&rsquo;</dt>
<dd><p>The channel layout of the incoming audio buffers.
Either a channel layout name from channel_layout_map in
&lsquo;<tt>libavutil/channel_layout.c</tt>&rsquo; or its corresponding integer representation
from the AV_CH_LAYOUT_* macros in &lsquo;<tt>libavutil/channel_layout.h</tt>&rsquo;
</p>
</dd>
<dt> &lsquo;<samp>channels</samp>&rsquo;</dt>
<dd><p>The number of channels of the incoming audio buffers.
If both <var>channels</var> and <var>channel_layout</var> are specified, then they
must be consistent.
</p>
</dd>
</dl>
<a name="Examples-9"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-9">26.1.1 Examples</a></h3>
<table><tr><td>&nbsp;</td><td><pre class="example">abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
</pre></td></tr></table>
<p>will instruct the source to accept planar 16bit signed stereo at 44100Hz.
Since the sample format with name &quot;s16p&quot; corresponds to the number
6 and the &quot;stereo&quot; channel layout corresponds to the value 0x3, this is
equivalent to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
</pre></td></tr></table>
<a name="aevalsrc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-aevalsrc">26.2 aevalsrc</a></h2>
<p>Generate an audio signal specified by an expression.
</p>
<p>This source accepts in input one or more expressions (one for each
channel), which are evaluated and used to generate a corresponding
audio signal.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>exprs</samp>&rsquo;</dt>
<dd><p>Set the &rsquo;|&rsquo;-separated expressions list for each separate channel. In case the
&lsquo;<samp>channel_layout</samp>&rsquo; option is not specified, the selected channel layout
depends on the number of provided expressions. Otherwise the last
specified expression is applied to the remaining output channels.
</p>
</dd>
<dt> &lsquo;<samp>channel_layout, c</samp>&rsquo;</dt>
<dd><p>Set the channel layout. The number of channels in the specified layout
must be equal to the number of specified expressions.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Set the minimum duration of the sourced audio. See the function
<code>av_parse_time()</code> for the accepted format.
Note that the resulting duration may be greater than the specified
duration, as the generated audio is always cut at the end of a
complete frame.
</p>
<p>If not specified, or the expressed duration is negative, the audio is
supposed to be generated forever.
</p>
</dd>
<dt> &lsquo;<samp>nb_samples, n</samp>&rsquo;</dt>
<dd><p>Set the number of samples per channel per each output frame,
default to 1024.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate, s</samp>&rsquo;</dt>
<dd><p>Specify the sample rate, default to 44100.
</p></dd>
</dl>
<p>Each expression in <var>exprs</var> can contain the following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>number of the evaluated sample, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>time of the evaluated sample expressed in seconds, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>sample rate
</p>
</dd>
</dl>
<a name="Examples-76"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-76">26.2.1 Examples</a></h3>
<ul>
<li>
Generate silence:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=0
</pre></td></tr></table>
</li><li>
Generate a sin signal with frequency of 440 Hz, set sample rate to
8000 Hz:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=&quot;sin(440*2*PI*t):s=8000&quot;
</pre></td></tr></table>
</li><li>
Generate a two channels signal, specify the channel layout (Front
Center + Back Center) explicitly:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=&quot;sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC&quot;
</pre></td></tr></table>
</li><li>
Generate white noise:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=&quot;-2+random(0)&quot;
</pre></td></tr></table>
</li><li>
Generate an amplitude modulated signal:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=&quot;sin(10*2*PI*t)*sin(880*2*PI*t)&quot;
</pre></td></tr></table>
</li><li>
Generate 2.5 Hz binaural beats on a 360 Hz carrier:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=&quot;0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)&quot;
</pre></td></tr></table>
</li></ul>
<a name="anullsrc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-anullsrc">26.3 anullsrc</a></h2>
<p>Null audio source, return unprocessed audio frames. It is mainly useful
as a template and to be employed in analysis / debugging tools, or as
the source for filters which ignore the input data (for example the sox
synth filter).
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>channel_layout, cl</samp>&rsquo;</dt>
<dd>
<p>Specify the channel layout, and can be either an integer or a string
representing a channel layout. The default value of <var>channel_layout</var>
is &quot;stereo&quot;.
</p>
<p>Check the channel_layout_map definition in
&lsquo;<tt>libavutil/channel_layout.c</tt>&rsquo; for the mapping between strings and
channel layout values.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate, r</samp>&rsquo;</dt>
<dd><p>Specify the sample rate, and defaults to 44100.
</p>
</dd>
<dt> &lsquo;<samp>nb_samples, n</samp>&rsquo;</dt>
<dd><p>Set the number of samples per requested frames.
</p>
</dd>
</dl>
<a name="Examples-42"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-42">26.3.1 Examples</a></h3>
<ul>
<li>
Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
<table><tr><td>&nbsp;</td><td><pre class="example">anullsrc=r=48000:cl=4
</pre></td></tr></table>
</li><li>
Do the same operation with a more obvious syntax:
<table><tr><td>&nbsp;</td><td><pre class="example">anullsrc=r=48000:cl=mono
</pre></td></tr></table>
</li></ul>
<p>All the parameters need to be explicitly defined.
</p>
<a name="flite"></a>
<h2 class="section"><a href="ffplay-all.html#toc-flite">26.4 flite</a></h2>
<p>Synthesize a voice utterance using the libflite library.
</p>
<p>To enable compilation of this filter you need to configure FFmpeg with
<code>--enable-libflite</code>.
</p>
<p>Note that the flite library is not thread-safe.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>list_voices</samp>&rsquo;</dt>
<dd><p>If set to 1, list the names of the available voices and exit
immediately. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>nb_samples, n</samp>&rsquo;</dt>
<dd><p>Set the maximum number of samples per frame. Default value is 512.
</p>
</dd>
<dt> &lsquo;<samp>textfile</samp>&rsquo;</dt>
<dd><p>Set the filename containing the text to speak.
</p>
</dd>
<dt> &lsquo;<samp>text</samp>&rsquo;</dt>
<dd><p>Set the text to speak.
</p>
</dd>
<dt> &lsquo;<samp>voice, v</samp>&rsquo;</dt>
<dd><p>Set the voice to use for the speech synthesis. Default value is
<code>kal</code>. See also the <var>list_voices</var> option.
</p></dd>
</dl>
<a name="Examples-56"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-56">26.4.1 Examples</a></h3>
<ul>
<li>
Read from file &lsquo;<tt>speech.txt</tt>&rsquo;, and synthetize the text using the
standard flite voice:
<table><tr><td>&nbsp;</td><td><pre class="example">flite=textfile=speech.txt
</pre></td></tr></table>
</li><li>
Read the specified text selecting the <code>slt</code> voice:
<table><tr><td>&nbsp;</td><td><pre class="example">flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
</pre></td></tr></table>
</li><li>
Input text to ffmpeg:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
</pre></td></tr></table>
</li><li>
Make &lsquo;<tt>ffplay</tt>&rsquo; speak the specified text, using <code>flite</code> and
the <code>lavfi</code> device:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
</pre></td></tr></table>
</li></ul>
<p>For more information about libflite, check:
<a href="http://www.speech.cs.cmu.edu/flite/">http://www.speech.cs.cmu.edu/flite/</a>
</p>
<a name="sine"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sine">26.5 sine</a></h2>
<p>Generate an audio signal made of a sine wave with amplitude 1/8.
</p>
<p>The audio signal is bit-exact.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>frequency, f</samp>&rsquo;</dt>
<dd><p>Set the carrier frequency. Default is 440 Hz.
</p>
</dd>
<dt> &lsquo;<samp>beep_factor, b</samp>&rsquo;</dt>
<dd><p>Enable a periodic beep every second with frequency <var>beep_factor</var> times
the carrier frequency. Default is 0, meaning the beep is disabled.
</p>
</dd>
<dt> &lsquo;<samp>sample_rate, r</samp>&rsquo;</dt>
<dd><p>Specify the sample rate, default is 44100.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Specify the duration of the generated audio stream.
</p>
</dd>
<dt> &lsquo;<samp>samples_per_frame</samp>&rsquo;</dt>
<dd><p>Set the number of samples per output frame, default is 1024.
</p></dd>
</dl>
<a name="Examples-72"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-72">26.5.1 Examples</a></h3>
<ul>
<li>
Generate a simple 440 Hz sine wave:
<table><tr><td>&nbsp;</td><td><pre class="example">sine
</pre></td></tr></table>
</li><li>
Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">sine=220:4:d=5
sine=f=220:b=4:d=5
sine=frequency=220:beep_factor=4:duration=5
</pre></td></tr></table>
</li></ul>
<a name="Audio-Sinks"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Audio-Sinks">27. Audio Sinks</a></h1>
<p>Below is a description of the currently available audio sinks.
</p>
<a name="abuffersink"></a>
<h2 class="section"><a href="ffplay-all.html#toc-abuffersink">27.1 abuffersink</a></h2>
<p>Buffer audio frames, and make them available to the end of filter chain.
</p>
<p>This sink is mainly intended for programmatic use, in particular
through the interface defined in &lsquo;<tt>libavfilter/buffersink.h</tt>&rsquo;
or the options system.
</p>
<p>It accepts a pointer to an AVABufferSinkContext structure, which
defines the incoming buffers&rsquo; formats, to be passed as the opaque
parameter to <code>avfilter_init_filter</code> for initialization.
</p>
<a name="anullsink"></a>
<h2 class="section"><a href="ffplay-all.html#toc-anullsink">27.2 anullsink</a></h2>
<p>Null audio sink, do absolutely nothing with the input audio. It is
mainly useful as a template and to be employed in analysis / debugging
tools.
</p>
<a name="Video-Filters"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Video-Filters">28. Video Filters</a></h1>
<p>When you configure your FFmpeg build, you can disable any of the
existing filters using <code>--disable-filters</code>.
The configure output will show the video filters included in your
build.
</p>
<p>Below is a description of the currently available video filters.
</p>
<a name="alphaextract"></a>
<h2 class="section"><a href="ffplay-all.html#toc-alphaextract">28.1 alphaextract</a></h2>
<p>Extract the alpha component from the input as a grayscale video. This
is especially useful with the <var>alphamerge</var> filter.
</p>
<a name="alphamerge"></a>
<h2 class="section"><a href="ffplay-all.html#toc-alphamerge">28.2 alphamerge</a></h2>
<p>Add or replace the alpha component of the primary input with the
grayscale value of a second input. This is intended for use with
<var>alphaextract</var> to allow the transmission or storage of frame
sequences that have alpha in a format that doesn&rsquo;t support an alpha
channel.
</p>
<p>For example, to reconstruct full frames from a normal YUV-encoded video
and a separate video created with <var>alphaextract</var>, you might use:
</p><table><tr><td>&nbsp;</td><td><pre class="example">movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
</pre></td></tr></table>
<p>Since this filter is designed for reconstruction, it operates on frame
sequences without considering timestamps, and terminates when either
input reaches end of stream. This will cause problems if your encoding
pipeline drops frames. If you&rsquo;re trying to apply an image as an
overlay to a video stream, consider the <var>overlay</var> filter instead.
</p>
<a name="ass"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ass">28.3 ass</a></h2>
<p>Same as the <a href="#subtitles">subtitles</a> filter, except that it doesn&rsquo;t require libavcodec
and libavformat to work. On the other hand, it is limited to ASS (Advanced
Substation Alpha) subtitles files.
</p>
<a name="bbox"></a>
<h2 class="section"><a href="ffplay-all.html#toc-bbox">28.4 bbox</a></h2>
<p>Compute the bounding box for the non-black pixels in the input frame
luminance plane.
</p>
<p>This filter computes the bounding box containing all the pixels with a
luminance value greater than the minimum allowed value.
The parameters describing the bounding box are printed on the filter
log.
</p>
<p>The filter accepts the following option:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>min_val</samp>&rsquo;</dt>
<dd><p>Set the minimal luminance value. Default is <code>16</code>.
</p></dd>
</dl>
<a name="blackdetect"></a>
<h2 class="section"><a href="ffplay-all.html#toc-blackdetect">28.5 blackdetect</a></h2>
<p>Detect video intervals that are (almost) completely black. Can be
useful to detect chapter transitions, commercials, or invalid
recordings. Output lines contains the time for the start, end and
duration of the detected black interval expressed in seconds.
</p>
<p>In order to display the output lines, you need to set the loglevel at
least to the AV_LOG_INFO value.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>black_min_duration, d</samp>&rsquo;</dt>
<dd><p>Set the minimum detected black duration expressed in seconds. It must
be a non-negative floating point number.
</p>
<p>Default value is 2.0.
</p>
</dd>
<dt> &lsquo;<samp>picture_black_ratio_th, pic_th</samp>&rsquo;</dt>
<dd><p>Set the threshold for considering a picture &quot;black&quot;.
Express the minimum value for the ratio:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>nb_black_pixels</var> / <var>nb_pixels</var>
</pre></td></tr></table>
<p>for which a picture is considered black.
Default value is 0.98.
</p>
</dd>
<dt> &lsquo;<samp>pixel_black_th, pix_th</samp>&rsquo;</dt>
<dd><p>Set the threshold for considering a pixel &quot;black&quot;.
</p>
<p>The threshold expresses the maximum pixel luminance value for which a
pixel is considered &quot;black&quot;. The provided value is scaled according to
the following equation:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>absolute_threshold</var> = <var>luminance_minimum_value</var> + <var>pixel_black_th</var> * <var>luminance_range_size</var>
</pre></td></tr></table>
<p><var>luminance_range_size</var> and <var>luminance_minimum_value</var> depend on
the input video format, the range is [0-255] for YUV full-range
formats and [16-235] for YUV non full-range formats.
</p>
<p>Default value is 0.10.
</p></dd>
</dl>
<p>The following example sets the maximum pixel threshold to the minimum
value, and detects only black intervals of 2 or more seconds:
</p><table><tr><td>&nbsp;</td><td><pre class="example">blackdetect=d=2:pix_th=0.00
</pre></td></tr></table>
<a name="blackframe"></a>
<h2 class="section"><a href="ffplay-all.html#toc-blackframe">28.6 blackframe</a></h2>
<p>Detect frames that are (almost) completely black. Can be useful to
detect chapter transitions or commercials. Output lines consist of
the frame number of the detected frame, the percentage of blackness,
the position in the file if known or -1 and the timestamp in seconds.
</p>
<p>In order to display the output lines, you need to set the loglevel at
least to the AV_LOG_INFO value.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>amount</samp>&rsquo;</dt>
<dd><p>Set the percentage of the pixels that have to be below the threshold, defaults
to <code>98</code>.
</p>
</dd>
<dt> &lsquo;<samp>threshold, thresh</samp>&rsquo;</dt>
<dd><p>Set the threshold below which a pixel value is considered black, defaults to
<code>32</code>.
</p>
</dd>
</dl>
<a name="blend"></a>
<h2 class="section"><a href="ffplay-all.html#toc-blend">28.7 blend</a></h2>
<p>Blend two video frames into each other.
</p>
<p>It takes two input streams and outputs one stream, the first input is the
&quot;top&quot; layer and second input is &quot;bottom&quot; layer.
Output terminates when shortest input terminates.
</p>
<p>A description of the accepted options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>c0_mode</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c1_mode</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c2_mode</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c3_mode</samp>&rsquo;</dt>
<dt> &lsquo;<samp>all_mode</samp>&rsquo;</dt>
<dd><p>Set blend mode for specific pixel component or all pixel components in case
of <var>all_mode</var>. Default value is <code>normal</code>.
</p>
<p>Available values for component modes are:
</p><dl compact="compact">
<dt> &lsquo;<samp>addition</samp>&rsquo;</dt>
<dt> &lsquo;<samp>and</samp>&rsquo;</dt>
<dt> &lsquo;<samp>average</samp>&rsquo;</dt>
<dt> &lsquo;<samp>burn</samp>&rsquo;</dt>
<dt> &lsquo;<samp>darken</samp>&rsquo;</dt>
<dt> &lsquo;<samp>difference</samp>&rsquo;</dt>
<dt> &lsquo;<samp>divide</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dodge</samp>&rsquo;</dt>
<dt> &lsquo;<samp>exclusion</samp>&rsquo;</dt>
<dt> &lsquo;<samp>hardlight</samp>&rsquo;</dt>
<dt> &lsquo;<samp>lighten</samp>&rsquo;</dt>
<dt> &lsquo;<samp>multiply</samp>&rsquo;</dt>
<dt> &lsquo;<samp>negation</samp>&rsquo;</dt>
<dt> &lsquo;<samp>normal</samp>&rsquo;</dt>
<dt> &lsquo;<samp>or</samp>&rsquo;</dt>
<dt> &lsquo;<samp>overlay</samp>&rsquo;</dt>
<dt> &lsquo;<samp>phoenix</samp>&rsquo;</dt>
<dt> &lsquo;<samp>pinlight</samp>&rsquo;</dt>
<dt> &lsquo;<samp>reflect</samp>&rsquo;</dt>
<dt> &lsquo;<samp>screen</samp>&rsquo;</dt>
<dt> &lsquo;<samp>softlight</samp>&rsquo;</dt>
<dt> &lsquo;<samp>subtract</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vividlight</samp>&rsquo;</dt>
<dt> &lsquo;<samp>xor</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>c0_opacity</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c1_opacity</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c2_opacity</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c3_opacity</samp>&rsquo;</dt>
<dt> &lsquo;<samp>all_opacity</samp>&rsquo;</dt>
<dd><p>Set blend opacity for specific pixel component or all pixel components in case
of <var>all_opacity</var>. Only used in combination with pixel component blend modes.
</p>
</dd>
<dt> &lsquo;<samp>c0_expr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c1_expr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c2_expr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c3_expr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>all_expr</samp>&rsquo;</dt>
<dd><p>Set blend expression for specific pixel component or all pixel components in case
of <var>all_expr</var>. Note that related mode options will be ignored if those are set.
</p>
<p>The expressions can use the following variables:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>N</samp>&rsquo;</dt>
<dd><p>The sequential number of the filtered frame, starting from <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>X</samp>&rsquo;</dt>
<dt> &lsquo;<samp>Y</samp>&rsquo;</dt>
<dd><p>the coordinates of the current sample
</p>
</dd>
<dt> &lsquo;<samp>W</samp>&rsquo;</dt>
<dt> &lsquo;<samp>H</samp>&rsquo;</dt>
<dd><p>the width and height of currently filtered plane
</p>
</dd>
<dt> &lsquo;<samp>SW</samp>&rsquo;</dt>
<dt> &lsquo;<samp>SH</samp>&rsquo;</dt>
<dd><p>Width and height scale depending on the currently filtered plane. It is the
ratio between the corresponding luma plane number of pixels and the current
plane ones. E.g. for YUV4:2:0 the values are <code>1,1</code> for the luma plane, and
<code>0.5,0.5</code> for chroma planes.
</p>
</dd>
<dt> &lsquo;<samp>T</samp>&rsquo;</dt>
<dd><p>Time of the current frame, expressed in seconds.
</p>
</dd>
<dt> &lsquo;<samp>TOP, A</samp>&rsquo;</dt>
<dd><p>Value of pixel component at current location for first video frame (top layer).
</p>
</dd>
<dt> &lsquo;<samp>BOTTOM, B</samp>&rsquo;</dt>
<dd><p>Value of pixel component at current location for second video frame (bottom layer).
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>shortest</samp>&rsquo;</dt>
<dd><p>Force termination when the shortest input terminates. Default is <code>0</code>.
</p></dd>
<dt> &lsquo;<samp>repeatlast</samp>&rsquo;</dt>
<dd><p>Continue applying the last bottom frame after the end of the stream. A value of
<code>0</code> disable the filter after the last frame of the bottom layer is reached.
Default is <code>1</code>.
</p></dd>
</dl>
<a name="Examples-45"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-45">28.7.1 Examples</a></h3>
<ul>
<li>
Apply transition from bottom layer to top layer in first 10 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
</pre></td></tr></table>
</li><li>
Apply 1x1 checkerboard effect:
<table><tr><td>&nbsp;</td><td><pre class="example">blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
</pre></td></tr></table>
</li><li>
Apply uncover left effect:
<table><tr><td>&nbsp;</td><td><pre class="example">blend=all_expr='if(gte(N*SW+X,W),A,B)'
</pre></td></tr></table>
</li><li>
Apply uncover down effect:
<table><tr><td>&nbsp;</td><td><pre class="example">blend=all_expr='if(gte(Y-N*SH,0),A,B)'
</pre></td></tr></table>
</li><li>
Apply uncover up-left effect:
<table><tr><td>&nbsp;</td><td><pre class="example">blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
</pre></td></tr></table>
</li></ul>
<a name="boxblur"></a>
<h2 class="section"><a href="ffplay-all.html#toc-boxblur">28.8 boxblur</a></h2>
<p>Apply boxblur algorithm to the input video.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_radius, lr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>luma_power, lp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_radius, cr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_power, cp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>alpha_radius, ar</samp>&rsquo;</dt>
<dt> &lsquo;<samp>alpha_power, ap</samp>&rsquo;</dt>
</dl>
<p>A description of the accepted options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_radius, lr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_radius, cr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>alpha_radius, ar</samp>&rsquo;</dt>
<dd><p>Set an expression for the box radius in pixels used for blurring the
corresponding input plane.
</p>
<p>The radius value must be a non-negative number, and must not be
greater than the value of the expression <code>min(w,h)/2</code> for the
luma and alpha planes, and of <code>min(cw,ch)/2</code> for the chroma
planes.
</p>
<p>Default value for &lsquo;<samp>luma_radius</samp>&rsquo; is &quot;2&quot;. If not specified,
&lsquo;<samp>chroma_radius</samp>&rsquo; and &lsquo;<samp>alpha_radius</samp>&rsquo; default to the
corresponding value set for &lsquo;<samp>luma_radius</samp>&rsquo;.
</p>
<p>The expressions can contain the following constants:
</p><dl compact="compact">
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>the input width and height in pixels
</p>
</dd>
<dt> &lsquo;<samp>cw</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ch</samp>&rsquo;</dt>
<dd><p>the input chroma image width and height in pixels
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>luma_power, lp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_power, cp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>alpha_power, ap</samp>&rsquo;</dt>
<dd><p>Specify how many times the boxblur filter is applied to the
corresponding plane.
</p>
<p>Default value for &lsquo;<samp>luma_power</samp>&rsquo; is 2. If not specified,
&lsquo;<samp>chroma_power</samp>&rsquo; and &lsquo;<samp>alpha_power</samp>&rsquo; default to the
corresponding value set for &lsquo;<samp>luma_power</samp>&rsquo;.
</p>
<p>A value of 0 will disable the effect.
</p></dd>
</dl>
<a name="Examples-84"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-84">28.8.1 Examples</a></h3>
<ul>
<li>
Apply a boxblur filter with luma, chroma, and alpha radius
set to 2:
<table><tr><td>&nbsp;</td><td><pre class="example">boxblur=luma_radius=2:luma_power=1
boxblur=2:1
</pre></td></tr></table>
</li><li>
Set luma radius to 2, alpha and chroma radius to 0:
<table><tr><td>&nbsp;</td><td><pre class="example">boxblur=2:1:cr=0:ar=0
</pre></td></tr></table>
</li><li>
Set luma and chroma radius to a fraction of the video dimension:
<table><tr><td>&nbsp;</td><td><pre class="example">boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
</pre></td></tr></table>
</li></ul>
<a name="colorbalance"></a>
<h2 class="section"><a href="ffplay-all.html#toc-colorbalance">28.9 colorbalance</a></h2>
<p>Modify intensity of primary colors (red, green and blue) of input frames.
</p>
<p>The filter allows an input frame to be adjusted in the shadows, midtones or highlights
regions for the red-cyan, green-magenta or blue-yellow balance.
</p>
<p>A positive adjustment value shifts the balance towards the primary color, a negative
value towards the complementary color.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>rs</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gs</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bs</samp>&rsquo;</dt>
<dd><p>Adjust red, green and blue shadows (darkest pixels).
</p>
</dd>
<dt> &lsquo;<samp>rm</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gm</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bm</samp>&rsquo;</dt>
<dd><p>Adjust red, green and blue midtones (medium pixels).
</p>
</dd>
<dt> &lsquo;<samp>rh</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gh</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bh</samp>&rsquo;</dt>
<dd><p>Adjust red, green and blue highlights (brightest pixels).
</p>
<p>Allowed ranges for options are <code>[-1.0, 1.0]</code>. Defaults are <code>0</code>.
</p></dd>
</dl>
<a name="Examples-23"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-23">28.9.1 Examples</a></h3>
<ul>
<li>
Add red color cast to shadows:
<table><tr><td>&nbsp;</td><td><pre class="example">colorbalance=rs=.3
</pre></td></tr></table>
</li></ul>
<a name="colorchannelmixer"></a>
<h2 class="section"><a href="ffplay-all.html#toc-colorchannelmixer">28.10 colorchannelmixer</a></h2>
<p>Adjust video input frames by re-mixing color channels.
</p>
<p>This filter modifies a color channel by adding the values associated to
the other channels of the same pixels. For example if the value to
modify is red, the output value will be:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>red</var>=<var>red</var>*<var>rr</var> + <var>blue</var>*<var>rb</var> + <var>green</var>*<var>rg</var> + <var>alpha</var>*<var>ra</var>
</pre></td></tr></table>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>rr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>rg</samp>&rsquo;</dt>
<dt> &lsquo;<samp>rb</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ra</samp>&rsquo;</dt>
<dd><p>Adjust contribution of input red, green, blue and alpha channels for output red channel.
Default is <code>1</code> for <var>rr</var>, and <code>0</code> for <var>rg</var>, <var>rb</var> and <var>ra</var>.
</p>
</dd>
<dt> &lsquo;<samp>gr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gg</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gb</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ga</samp>&rsquo;</dt>
<dd><p>Adjust contribution of input red, green, blue and alpha channels for output green channel.
Default is <code>1</code> for <var>gg</var>, and <code>0</code> for <var>gr</var>, <var>gb</var> and <var>ga</var>.
</p>
</dd>
<dt> &lsquo;<samp>br</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bg</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bb</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ba</samp>&rsquo;</dt>
<dd><p>Adjust contribution of input red, green, blue and alpha channels for output blue channel.
Default is <code>1</code> for <var>bb</var>, and <code>0</code> for <var>br</var>, <var>bg</var> and <var>ba</var>.
</p>
</dd>
<dt> &lsquo;<samp>ar</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ag</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ab</samp>&rsquo;</dt>
<dt> &lsquo;<samp>aa</samp>&rsquo;</dt>
<dd><p>Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
Default is <code>1</code> for <var>aa</var>, and <code>0</code> for <var>ar</var>, <var>ag</var> and <var>ab</var>.
</p>
<p>Allowed ranges for options are <code>[-2.0, 2.0]</code>.
</p></dd>
</dl>
<a name="Examples-54"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-54">28.10.1 Examples</a></h3>
<ul>
<li>
Convert source to grayscale:
<table><tr><td>&nbsp;</td><td><pre class="example">colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
</pre></td></tr></table>
</li><li>
Simulate sepia tones:
<table><tr><td>&nbsp;</td><td><pre class="example">colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
</pre></td></tr></table>
</li></ul>
<a name="colormatrix"></a>
<h2 class="section"><a href="ffplay-all.html#toc-colormatrix">28.11 colormatrix</a></h2>
<p>Convert color matrix.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>src</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dst</samp>&rsquo;</dt>
<dd><p>Specify the source and destination color matrix. Both values must be
specified.
</p>
<p>The accepted values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>bt709</samp>&rsquo;</dt>
<dd><p>BT.709
</p>
</dd>
<dt> &lsquo;<samp>bt601</samp>&rsquo;</dt>
<dd><p>BT.601
</p>
</dd>
<dt> &lsquo;<samp>smpte240m</samp>&rsquo;</dt>
<dd><p>SMPTE-240M
</p>
</dd>
<dt> &lsquo;<samp>fcc</samp>&rsquo;</dt>
<dd><p>FCC
</p></dd>
</dl>
</dd>
</dl>
<p>For example to convert from BT.601 to SMPTE-240M, use the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">colormatrix=bt601:smpte240m
</pre></td></tr></table>
<a name="copy"></a>
<h2 class="section"><a href="ffplay-all.html#toc-copy">28.12 copy</a></h2>
<p>Copy the input source unchanged to the output. Mainly useful for
testing purposes.
</p>
<a name="crop"></a>
<h2 class="section"><a href="ffplay-all.html#toc-crop">28.13 crop</a></h2>
<p>Crop the input video to given dimensions.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>w, out_w</samp>&rsquo;</dt>
<dd><p>Width of the output video. It defaults to <code>iw</code>.
This expression is evaluated only once during the filter
configuration.
</p>
</dd>
<dt> &lsquo;<samp>h, out_h</samp>&rsquo;</dt>
<dd><p>Height of the output video. It defaults to <code>ih</code>.
This expression is evaluated only once during the filter
configuration.
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dd><p>Horizontal position, in the input video, of the left edge of the output video.
It defaults to <code>(in_w-out_w)/2</code>.
This expression is evaluated per-frame.
</p>
</dd>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>Vertical position, in the input video, of the top edge of the output video.
It defaults to <code>(in_h-out_h)/2</code>.
This expression is evaluated per-frame.
</p>
</dd>
<dt> &lsquo;<samp>keep_aspect</samp>&rsquo;</dt>
<dd><p>If set to 1 will force the output display aspect ratio
to be the same of the input, by changing the output sample aspect
ratio. It defaults to 0.
</p></dd>
</dl>
<p>The <var>out_w</var>, <var>out_h</var>, <var>x</var>, <var>y</var> parameters are
expressions containing the following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>the computed values for <var>x</var> and <var>y</var>. They are evaluated for
each new frame.
</p>
</dd>
<dt> &lsquo;<samp>in_w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>in_h</samp>&rsquo;</dt>
<dd><p>the input width and height
</p>
</dd>
<dt> &lsquo;<samp>iw</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ih</samp>&rsquo;</dt>
<dd><p>same as <var>in_w</var> and <var>in_h</var>
</p>
</dd>
<dt> &lsquo;<samp>out_w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>out_h</samp>&rsquo;</dt>
<dd><p>the output (cropped) width and height
</p>
</dd>
<dt> &lsquo;<samp>ow</samp>&rsquo;</dt>
<dt> &lsquo;<samp>oh</samp>&rsquo;</dt>
<dd><p>same as <var>out_w</var> and <var>out_h</var>
</p>
</dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>same as <var>iw</var> / <var>ih</var>
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>input sample aspect ratio
</p>
</dd>
<dt> &lsquo;<samp>dar</samp>&rsquo;</dt>
<dd><p>input display aspect ratio, it is the same as (<var>iw</var> / <var>ih</var>) * <var>sar</var>
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>the number of input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>the position in the file of the input frame, NAN if unknown
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>timestamp expressed in seconds, NAN if the input timestamp is unknown
</p>
</dd>
</dl>
<p>The expression for <var>out_w</var> may depend on the value of <var>out_h</var>,
and the expression for <var>out_h</var> may depend on <var>out_w</var>, but they
cannot depend on <var>x</var> and <var>y</var>, as <var>x</var> and <var>y</var> are
evaluated after <var>out_w</var> and <var>out_h</var>.
</p>
<p>The <var>x</var> and <var>y</var> parameters specify the expressions for the
position of the top-left corner of the output (non-cropped) area. They
are evaluated for each frame. If the evaluated value is not valid, it
is approximated to the nearest valid value.
</p>
<p>The expression for <var>x</var> may depend on <var>y</var>, and the expression
for <var>y</var> may depend on <var>x</var>.
</p>
<a name="Examples-69"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-69">28.13.1 Examples</a></h3>
<ul>
<li>
Crop area with size 100x100 at position (12,34).
<table><tr><td>&nbsp;</td><td><pre class="example">crop=100:100:12:34
</pre></td></tr></table>
<p>Using named options, the example above becomes:
</p><table><tr><td>&nbsp;</td><td><pre class="example">crop=w=100:h=100:x=12:y=34
</pre></td></tr></table>
</li><li>
Crop the central input area with size 100x100:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=100:100
</pre></td></tr></table>
</li><li>
Crop the central input area with size 2/3 of the input video:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=2/3*in_w:2/3*in_h
</pre></td></tr></table>
</li><li>
Crop the input video central square:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=out_w=in_h
crop=in_h
</pre></td></tr></table>
</li><li>
Delimit the rectangle with the top-left corner placed at position
100:100 and the right-bottom corner corresponding to the right-bottom
corner of the input image:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w-100:in_h-100:100:100
</pre></td></tr></table>
</li><li>
Crop 10 pixels from the left and right borders, and 20 pixels from
the top and bottom borders
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w-2*10:in_h-2*20
</pre></td></tr></table>
</li><li>
Keep only the bottom right quarter of the input image:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w/2:in_h/2:in_w/2:in_h/2
</pre></td></tr></table>
</li><li>
Crop height for getting Greek harmony:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w:1/PHI*in_w
</pre></td></tr></table>
</li><li>
Appply trembling effect:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)
</pre></td></tr></table>
</li><li>
Apply erratic camera effect depending on timestamp:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)&quot;
</pre></td></tr></table>
</li><li>
Set x depending on the value of y:
<table><tr><td>&nbsp;</td><td><pre class="example">crop=in_w/2:in_h/2:y:10+10*sin(n/10)
</pre></td></tr></table>
</li></ul>
<a name="cropdetect"></a>
<h2 class="section"><a href="ffplay-all.html#toc-cropdetect">28.14 cropdetect</a></h2>
<p>Auto-detect crop size.
</p>
<p>Calculate necessary cropping parameters and prints the recommended
parameters through the logging system. The detected dimensions
correspond to the non-black area of the input video.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>limit</samp>&rsquo;</dt>
<dd><p>Set higher black value threshold, which can be optionally specified
from nothing (0) to everything (255). An intensity value greater
to the set value is considered non-black. Default value is 24.
</p>
</dd>
<dt> &lsquo;<samp>round</samp>&rsquo;</dt>
<dd><p>Set the value for which the width/height should be divisible by. The
offset is automatically adjusted to center the video. Use 2 to get
only even dimensions (needed for 4:2:2 video). 16 is best when
encoding to most video codecs. Default value is 16.
</p>
</dd>
<dt> &lsquo;<samp>reset_count, reset</samp>&rsquo;</dt>
<dd><p>Set the counter that determines after how many frames cropdetect will
reset the previously detected largest video area and start over to
detect the current optimal crop area. Default value is 0.
</p>
<p>This can be useful when channel logos distort the video area. 0
indicates never reset and return the largest area encountered during
playback.
</p></dd>
</dl>
<p><a name="curves"></a>
</p><a name="curves-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-curves-1">28.15 curves</a></h2>
<p>Apply color adjustments using curves.
</p>
<p>This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
component (red, green and blue) has its values defined by <var>N</var> key points
tied from each other using a smooth curve. The x-axis represents the pixel
values from the input frame, and the y-axis the new pixel values to be set for
the output frame.
</p>
<p>By default, a component curve is defined by the two points <var>(0;0)</var> and
<var>(1;1)</var>. This creates a straight line where each original pixel value is
&quot;adjusted&quot; to its own value, which means no change to the image.
</p>
<p>The filter allows you to redefine these two points and add some more. A new
curve (using a natural cubic spline interpolation) will be define to pass
smoothly through all these new coordinates. The new defined points needs to be
strictly increasing over the x-axis, and their <var>x</var> and <var>y</var> values must
be in the <var>[0;1]</var> interval. If the computed curves happened to go outside
the vector spaces, the values will be clipped accordingly.
</p>
<p>If there is no key point defined in <code>x=0</code>, the filter will automatically
insert a <var>(0;0)</var> point. In the same way, if there is no key point defined
in <code>x=1</code>, the filter will automatically insert a <var>(1;1)</var> point.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>preset</samp>&rsquo;</dt>
<dd><p>Select one of the available color presets. This option can be used in addition
to the &lsquo;<samp>r</samp>&rsquo;, &lsquo;<samp>g</samp>&rsquo;, &lsquo;<samp>b</samp>&rsquo; parameters; in this case, the later
options takes priority on the preset values.
Available presets are:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dt> &lsquo;<samp>color_negative</samp>&rsquo;</dt>
<dt> &lsquo;<samp>cross_process</samp>&rsquo;</dt>
<dt> &lsquo;<samp>darker</samp>&rsquo;</dt>
<dt> &lsquo;<samp>increase_contrast</samp>&rsquo;</dt>
<dt> &lsquo;<samp>lighter</samp>&rsquo;</dt>
<dt> &lsquo;<samp>linear_contrast</samp>&rsquo;</dt>
<dt> &lsquo;<samp>medium_contrast</samp>&rsquo;</dt>
<dt> &lsquo;<samp>negative</samp>&rsquo;</dt>
<dt> &lsquo;<samp>strong_contrast</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vintage</samp>&rsquo;</dt>
</dl>
<p>Default is <code>none</code>.
</p></dd>
<dt> &lsquo;<samp>master, m</samp>&rsquo;</dt>
<dd><p>Set the master key points. These points will define a second pass mapping. It
is sometimes called a &quot;luminance&quot; or &quot;value&quot; mapping. It can be used with
&lsquo;<samp>r</samp>&rsquo;, &lsquo;<samp>g</samp>&rsquo;, &lsquo;<samp>b</samp>&rsquo; or &lsquo;<samp>all</samp>&rsquo; since it acts like a
post-processing LUT.
</p></dd>
<dt> &lsquo;<samp>red, r</samp>&rsquo;</dt>
<dd><p>Set the key points for the red component.
</p></dd>
<dt> &lsquo;<samp>green, g</samp>&rsquo;</dt>
<dd><p>Set the key points for the green component.
</p></dd>
<dt> &lsquo;<samp>blue, b</samp>&rsquo;</dt>
<dd><p>Set the key points for the blue component.
</p></dd>
<dt> &lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Set the key points for all components (not including master).
Can be used in addition to the other key points component
options. In this case, the unset component(s) will fallback on this
&lsquo;<samp>all</samp>&rsquo; setting.
</p></dd>
<dt> &lsquo;<samp>psfile</samp>&rsquo;</dt>
<dd><p>Specify a Photoshop curves file (<code>.asv</code>) to import the settings from.
</p></dd>
</dl>
<p>To avoid some filtergraph syntax conflicts, each key points list need to be
defined using the following syntax: <code>x0/y0 x1/y1 x2/y2 ...</code>.
</p>
<a name="Examples-71"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-71">28.15.1 Examples</a></h3>
<ul>
<li>
Increase slightly the middle level of blue:
<table><tr><td>&nbsp;</td><td><pre class="example">curves=blue='0.5/0.58'
</pre></td></tr></table>
</li><li>
Vintage effect:
<table><tr><td>&nbsp;</td><td><pre class="example">curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
</pre></td></tr></table>
<p>Here we obtain the following coordinates for each components:
</p><dl compact="compact">
<dt> <var>red</var></dt>
<dd><p><code>(0;0.11) (0.42;0.51) (1;0.95)</code>
</p></dd>
<dt> <var>green</var></dt>
<dd><p><code>(0;0) (0.50;0.48) (1;1)</code>
</p></dd>
<dt> <var>blue</var></dt>
<dd><p><code>(0;0.22) (0.49;0.44) (1;0.80)</code>
</p></dd>
</dl>
</li><li>
The previous example can also be achieved with the associated built-in preset:
<table><tr><td>&nbsp;</td><td><pre class="example">curves=preset=vintage
</pre></td></tr></table>
</li><li>
Or simply:
<table><tr><td>&nbsp;</td><td><pre class="example">curves=vintage
</pre></td></tr></table>
</li><li>
Use a Photoshop preset and redefine the points of the green component:
<table><tr><td>&nbsp;</td><td><pre class="example">curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
</pre></td></tr></table>
</li></ul>
<a name="dctdnoiz"></a>
<h2 class="section"><a href="ffplay-all.html#toc-dctdnoiz">28.16 dctdnoiz</a></h2>
<p>Denoise frames using 2D DCT (frequency domain filtering).
</p>
<p>This filter is not designed for real time and can be extremely slow.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>sigma, s</samp>&rsquo;</dt>
<dd><p>Set the noise sigma constant.
</p>
<p>This <var>sigma</var> defines a hard threshold of <code>3 * sigma</code>; every DCT
coefficient (absolute value) below this threshold with be dropped.
</p>
<p>If you need a more advanced filtering, see &lsquo;<samp>expr</samp>&rsquo;.
</p>
<p>Default is <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>overlap</samp>&rsquo;</dt>
<dd><p>Set number overlapping pixels for each block. Each block is of size
<code>16x16</code>. Since the filter can be slow, you may want to reduce this value,
at the cost of a less effective filter and the risk of various artefacts.
</p>
<p>If the overlapping value doesn&rsquo;t allow to process the whole input width or
height, a warning will be displayed and according borders won&rsquo;t be denoised.
</p>
<p>Default value is <code>15</code>.
</p>
</dd>
<dt> &lsquo;<samp>expr, e</samp>&rsquo;</dt>
<dd><p>Set the coefficient factor expression.
</p>
<p>For each coefficient of a DCT block, this expression will be evaluated as a
multiplier value for the coefficient.
</p>
<p>If this is option is set, the &lsquo;<samp>sigma</samp>&rsquo; option will be ignored.
</p>
<p>The absolute value of the coefficient can be accessed through the <var>c</var>
variable.
</p></dd>
</dl>
<a name="Examples-21"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-21">28.16.1 Examples</a></h3>
<p>Apply a denoise with a &lsquo;<samp>sigma</samp>&rsquo; of <code>4.5</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">dctdnoiz=4.5
</pre></td></tr></table>
<p>The same operation can be achieved using the expression system:
</p><table><tr><td>&nbsp;</td><td><pre class="example">dctdnoiz=e='gte(c, 4.5*3)'
</pre></td></tr></table>
<p><a name="decimate"></a>
</p><a name="decimate-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-decimate-1">28.17 decimate</a></h2>
<p>Drop duplicated frames at regular intervals.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>cycle</samp>&rsquo;</dt>
<dd><p>Set the number of frames from which one will be dropped. Setting this to
<var>N</var> means one frame in every batch of <var>N</var> frames will be dropped.
Default is <code>5</code>.
</p>
</dd>
<dt> &lsquo;<samp>dupthresh</samp>&rsquo;</dt>
<dd><p>Set the threshold for duplicate detection. If the difference metric for a frame
is less than or equal to this value, then it is declared as duplicate. Default
is <code>1.1</code>
</p>
</dd>
<dt> &lsquo;<samp>scthresh</samp>&rsquo;</dt>
<dd><p>Set scene change threshold. Default is <code>15</code>.
</p>
</dd>
<dt> &lsquo;<samp>blockx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>blocky</samp>&rsquo;</dt>
<dd><p>Set the size of the x and y-axis blocks used during metric calculations.
Larger blocks give better noise suppression, but also give worse detection of
small movements. Must be a power of two. Default is <code>32</code>.
</p>
</dd>
<dt> &lsquo;<samp>ppsrc</samp>&rsquo;</dt>
<dd><p>Mark main input as a pre-processed input and activate clean source input
stream. This allows the input to be pre-processed with various filters to help
the metrics calculation while keeping the frame selection lossless. When set to
<code>1</code>, the first stream is for the pre-processed input, and the second
stream is the clean source from where the kept frames are chosen. Default is
<code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
<dd><p>Set whether or not chroma is considered in the metric calculations. Default is
<code>1</code>.
</p></dd>
</dl>
<a name="dejudder"></a>
<h2 class="section"><a href="ffplay-all.html#toc-dejudder">28.18 dejudder</a></h2>
<p>Remove judder produced by partially interlaced telecined content.
</p>
<p>Judder can be introduced, for instance, by <a href="#pullup">pullup</a> filter. If the original
source was partially telecined content then the output of <code>pullup,dejudder</code>
will have a variable frame rate. May change the recorded frame rate of the
container. Aside from that change, this filter will not affect constant frame
rate video.
</p>
<p>The option available in this filter is:
</p><dl compact="compact">
<dt> &lsquo;<samp>cycle</samp>&rsquo;</dt>
<dd><p>Specify the length of the window over which the judder repeats.
</p>
<p>Accepts any interger greater than 1. Useful values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>4</samp>&rsquo;</dt>
<dd><p>If the original was telecined from 24 to 30 fps (Film to NTSC).
</p>
</dd>
<dt> &lsquo;<samp>5</samp>&rsquo;</dt>
<dd><p>If the original was telecined from 25 to 30 fps (PAL to NTSC).
</p>
</dd>
<dt> &lsquo;<samp>20</samp>&rsquo;</dt>
<dd><p>If a mixture of the two.
</p></dd>
</dl>
<p>The default is &lsquo;<samp>4</samp>&rsquo;.
</p></dd>
</dl>
<a name="delogo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-delogo">28.19 delogo</a></h2>
<p>Suppress a TV station logo by a simple interpolation of the surrounding
pixels. Just set a rectangle covering the logo and watch it disappear
(and sometimes something even uglier appear - your mileage may vary).
</p>
<p>This filter accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>Specify the top left corner coordinates of the logo. They must be
specified.
</p>
</dd>
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Specify the width and height of the logo to clear. They must be
specified.
</p>
</dd>
<dt> &lsquo;<samp>band, t</samp>&rsquo;</dt>
<dd><p>Specify the thickness of the fuzzy edge of the rectangle (added to
<var>w</var> and <var>h</var>). The default value is 4.
</p>
</dd>
<dt> &lsquo;<samp>show</samp>&rsquo;</dt>
<dd><p>When set to 1, a green rectangle is drawn on the screen to simplify
finding the right <var>x</var>, <var>y</var>, <var>w</var>, and <var>h</var> parameters.
The default value is 0.
</p>
<p>The rectangle is drawn on the outermost pixels which will be (partly)
replaced with interpolated values. The values of the next pixels
immediately outside this rectangle in each direction will be used to
compute the interpolated pixel values inside the rectangle.
</p>
</dd>
</dl>
<a name="Examples-49"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-49">28.19.1 Examples</a></h3>
<ul>
<li>
Set a rectangle covering the area with top left corner coordinates 0,0
and size 100x77, setting a band of size 10:
<table><tr><td>&nbsp;</td><td><pre class="example">delogo=x=0:y=0:w=100:h=77:band=10
</pre></td></tr></table>
</li></ul>
<a name="deshake"></a>
<h2 class="section"><a href="ffplay-all.html#toc-deshake">28.20 deshake</a></h2>
<p>Attempt to fix small changes in horizontal and/or vertical shift. This
filter helps remove camera shake from hand-holding a camera, bumping a
tripod, moving on a vehicle, etc.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Specify a rectangular area where to limit the search for motion
vectors.
If desired the search for motion vectors can be limited to a
rectangular area of the frame defined by its top left corner, width
and height. These parameters have the same meaning as the drawbox
filter which can be used to visualise the position of the bounding
box.
</p>
<p>This is useful when simultaneous movement of subjects within the frame
might be confused for camera motion by the motion vector search.
</p>
<p>If any or all of <var>x</var>, <var>y</var>, <var>w</var> and <var>h</var> are set to -1
then the full frame is used. This allows later options to be set
without specifying the bounding box for the motion vector search.
</p>
<p>Default - search the whole frame.
</p>
</dd>
<dt> &lsquo;<samp>rx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ry</samp>&rsquo;</dt>
<dd><p>Specify the maximum extent of movement in x and y directions in the
range 0-64 pixels. Default 16.
</p>
</dd>
<dt> &lsquo;<samp>edge</samp>&rsquo;</dt>
<dd><p>Specify how to generate pixels to fill blanks at the edge of the
frame. Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>blank, 0</samp>&rsquo;</dt>
<dd><p>Fill zeroes at blank locations
</p></dd>
<dt> &lsquo;<samp>original, 1</samp>&rsquo;</dt>
<dd><p>Original image at blank locations
</p></dd>
<dt> &lsquo;<samp>clamp, 2</samp>&rsquo;</dt>
<dd><p>Extruded edge value at blank locations
</p></dd>
<dt> &lsquo;<samp>mirror, 3</samp>&rsquo;</dt>
<dd><p>Mirrored edge at blank locations
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>mirror</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>blocksize</samp>&rsquo;</dt>
<dd><p>Specify the blocksize to use for motion search. Range 4-128 pixels,
default 8.
</p>
</dd>
<dt> &lsquo;<samp>contrast</samp>&rsquo;</dt>
<dd><p>Specify the contrast threshold for blocks. Only blocks with more than
the specified contrast (difference between darkest and lightest
pixels) will be considered. Range 1-255, default 125.
</p>
</dd>
<dt> &lsquo;<samp>search</samp>&rsquo;</dt>
<dd><p>Specify the search strategy. Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>exhaustive, 0</samp>&rsquo;</dt>
<dd><p>Set exhaustive search
</p></dd>
<dt> &lsquo;<samp>less, 1</samp>&rsquo;</dt>
<dd><p>Set less exhaustive search.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>exhaustive</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>filename</samp>&rsquo;</dt>
<dd><p>If set then a detailed log of the motion search is written to the
specified file.
</p>
</dd>
<dt> &lsquo;<samp>opencl</samp>&rsquo;</dt>
<dd><p>If set to 1, specify using OpenCL capabilities, only available if
FFmpeg was configured with <code>--enable-opencl</code>. Default value is 0.
</p>
</dd>
</dl>
<a name="drawbox"></a>
<h2 class="section"><a href="ffplay-all.html#toc-drawbox">28.21 drawbox</a></h2>
<p>Draw a colored box on the input image.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>The expressions which specify the top left corner coordinates of the box. Default to 0.
</p>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>height, h</samp>&rsquo;</dt>
<dd><p>The expressions which specify the width and height of the box, if 0 they are interpreted as
the input width and height. Default to 0.
</p>
</dd>
<dt> &lsquo;<samp>color, c</samp>&rsquo;</dt>
<dd><p>Specify the color of the box to write. For the general syntax of this option,
check the &quot;Color&quot; section in the ffmpeg-utils manual. If the special
value <code>invert</code> is used, the box edge color is the same as the
video with inverted luma.
</p>
</dd>
<dt> &lsquo;<samp>thickness, t</samp>&rsquo;</dt>
<dd><p>The expression which sets the thickness of the box edge. Default value is <code>3</code>.
</p>
<p>See below for the list of accepted constants.
</p></dd>
</dl>
<p>The parameters for <var>x</var>, <var>y</var>, <var>w</var> and <var>h</var> and <var>t</var> are expressions containing the
following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>dar</samp>&rsquo;</dt>
<dd><p>The input display aspect ratio, it is the same as (<var>w</var> / <var>h</var>) * <var>sar</var>.
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p>
</dd>
<dt> &lsquo;<samp>in_h, ih</samp>&rsquo;</dt>
<dt> &lsquo;<samp>in_w, iw</samp>&rsquo;</dt>
<dd><p>The input width and height.
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>The input sample aspect ratio.
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>The x and y offset coordinates where the box is drawn.
</p>
</dd>
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>The width and height of the drawn box.
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>The thickness of the drawn box.
</p>
<p>These constants allow the <var>x</var>, <var>y</var>, <var>w</var>, <var>h</var> and <var>t</var> expressions to refer to
each other, so you may for example specify <code>y=x/dar</code> or <code>h=w/dar</code>.
</p>
</dd>
</dl>
<a name="Examples-40"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-40">28.21.1 Examples</a></h3>
<ul>
<li>
Draw a black box around the edge of the input image:
<table><tr><td>&nbsp;</td><td><pre class="example">drawbox
</pre></td></tr></table>
</li><li>
Draw a box with color red and an opacity of 50%:
<table><tr><td>&nbsp;</td><td><pre class="example">drawbox=10:20:200:60:red@0.5
</pre></td></tr></table>
<p>The previous example can be specified as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">drawbox=x=10:y=20:w=200:h=60:color=red@0.5
</pre></td></tr></table>
</li><li>
Fill the box with pink color:
<table><tr><td>&nbsp;</td><td><pre class="example">drawbox=x=10:y=10:w=100:h=100:color=pink@0.5:t=max
</pre></td></tr></table>
</li><li>
Draw a 2-pixel red 2.40:1 mask:
<table><tr><td>&nbsp;</td><td><pre class="example">drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
</pre></td></tr></table>
</li></ul>
<a name="drawgrid"></a>
<h2 class="section"><a href="ffplay-all.html#toc-drawgrid">28.22 drawgrid</a></h2>
<p>Draw a grid on the input image.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
</p>
</dd>
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>height, h</samp>&rsquo;</dt>
<dd><p>The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
input width and height, respectively, minus <code>thickness</code>, so image gets
framed. Default to 0.
</p>
</dd>
<dt> &lsquo;<samp>color, c</samp>&rsquo;</dt>
<dd><p>Specify the color of the grid. For the general syntax of this option,
check the &quot;Color&quot; section in the ffmpeg-utils manual. If the special
value <code>invert</code> is used, the grid color is the same as the
video with inverted luma.
</p>
</dd>
<dt> &lsquo;<samp>thickness, t</samp>&rsquo;</dt>
<dd><p>The expression which sets the thickness of the grid line. Default value is <code>1</code>.
</p>
<p>See below for the list of accepted constants.
</p></dd>
</dl>
<p>The parameters for <var>x</var>, <var>y</var>, <var>w</var> and <var>h</var> and <var>t</var> are expressions containing the
following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>dar</samp>&rsquo;</dt>
<dd><p>The input display aspect ratio, it is the same as (<var>w</var> / <var>h</var>) * <var>sar</var>.
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p>
</dd>
<dt> &lsquo;<samp>in_h, ih</samp>&rsquo;</dt>
<dt> &lsquo;<samp>in_w, iw</samp>&rsquo;</dt>
<dd><p>The input grid cell width and height.
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>The input sample aspect ratio.
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>The x and y coordinates of some point of grid intersection (meant to configure offset).
</p>
</dd>
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>The width and height of the drawn cell.
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>The thickness of the drawn cell.
</p>
<p>These constants allow the <var>x</var>, <var>y</var>, <var>w</var>, <var>h</var> and <var>t</var> expressions to refer to
each other, so you may for example specify <code>y=x/dar</code> or <code>h=w/dar</code>.
</p>
</dd>
</dl>
<a name="Examples-37"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-37">28.22.1 Examples</a></h3>
<ul>
<li>
Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
<table><tr><td>&nbsp;</td><td><pre class="example">drawgrid=width=100:height=100:thickness=2:color=red@0.5
</pre></td></tr></table>
</li><li>
Draw a white 3x3 grid with an opacity of 50%:
<table><tr><td>&nbsp;</td><td><pre class="example">drawgrid=w=iw/3:h=ih/3:t=2:c=white@0.5
</pre></td></tr></table>
</li></ul>
<p><a name="drawtext"></a>
</p><a name="drawtext-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-drawtext-1">28.23 drawtext</a></h2>
<p>Draw text string or text from specified file on top of video using the
libfreetype library.
</p>
<p>To enable compilation of this filter you need to configure FFmpeg with
<code>--enable-libfreetype</code>.
</p>
<a name="Syntax-2"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Syntax-2">28.23.1 Syntax</a></h3>
<p>The description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>box</samp>&rsquo;</dt>
<dd><p>Used to draw a box around text using background color.
Value should be either 1 (enable) or 0 (disable).
The default value of <var>box</var> is 0.
</p>
</dd>
<dt> &lsquo;<samp>boxcolor</samp>&rsquo;</dt>
<dd><p>The color to be used for drawing box around text. For the syntax of this
option, check the &quot;Color&quot; section in the ffmpeg-utils manual.
</p>
<p>The default value of <var>boxcolor</var> is &quot;white&quot;.
</p>
</dd>
<dt> &lsquo;<samp>borderw</samp>&rsquo;</dt>
<dd><p>Set the width of the border to be drawn around the text using <var>bordercolor</var>.
The default value of <var>borderw</var> is 0.
</p>
</dd>
<dt> &lsquo;<samp>bordercolor</samp>&rsquo;</dt>
<dd><p>Set the color to be used for drawing border around text. For the syntax of this
option, check the &quot;Color&quot; section in the ffmpeg-utils manual.
</p>
<p>The default value of <var>bordercolor</var> is &quot;black&quot;.
</p>
</dd>
<dt> &lsquo;<samp>expansion</samp>&rsquo;</dt>
<dd><p>Select how the <var>text</var> is expanded. Can be either <code>none</code>,
<code>strftime</code> (deprecated) or
<code>normal</code> (default). See the <a href="#drawtext_005fexpansion">Text expansion</a> section
below for details.
</p>
</dd>
<dt> &lsquo;<samp>fix_bounds</samp>&rsquo;</dt>
<dd><p>If true, check and fix text coords to avoid clipping.
</p>
</dd>
<dt> &lsquo;<samp>fontcolor</samp>&rsquo;</dt>
<dd><p>The color to be used for drawing fonts. For the syntax of this option, check
the &quot;Color&quot; section in the ffmpeg-utils manual.
</p>
<p>The default value of <var>fontcolor</var> is &quot;black&quot;.
</p>
</dd>
<dt> &lsquo;<samp>fontfile</samp>&rsquo;</dt>
<dd><p>The font file to be used for drawing text. Path must be included.
This parameter is mandatory.
</p>
</dd>
<dt> &lsquo;<samp>fontsize</samp>&rsquo;</dt>
<dd><p>The font size to be used for drawing text.
The default value of <var>fontsize</var> is 16.
</p>
</dd>
<dt> &lsquo;<samp>ft_load_flags</samp>&rsquo;</dt>
<dd><p>Flags to be used for loading the fonts.
</p>
<p>The flags map the corresponding flags supported by libfreetype, and are
a combination of the following values:
</p><dl compact="compact">
<dt> <var>default</var></dt>
<dt> <var>no_scale</var></dt>
<dt> <var>no_hinting</var></dt>
<dt> <var>render</var></dt>
<dt> <var>no_bitmap</var></dt>
<dt> <var>vertical_layout</var></dt>
<dt> <var>force_autohint</var></dt>
<dt> <var>crop_bitmap</var></dt>
<dt> <var>pedantic</var></dt>
<dt> <var>ignore_global_advance_width</var></dt>
<dt> <var>no_recurse</var></dt>
<dt> <var>ignore_transform</var></dt>
<dt> <var>monochrome</var></dt>
<dt> <var>linear_design</var></dt>
<dt> <var>no_autohint</var></dt>
</dl>
<p>Default value is &quot;default&quot;.
</p>
<p>For more information consult the documentation for the FT_LOAD_*
libfreetype flags.
</p>
</dd>
<dt> &lsquo;<samp>shadowcolor</samp>&rsquo;</dt>
<dd><p>The color to be used for drawing a shadow behind the drawn text. For the
syntax of this option, check the &quot;Color&quot; section in the ffmpeg-utils manual.
</p>
<p>The default value of <var>shadowcolor</var> is &quot;black&quot;.
</p>
</dd>
<dt> &lsquo;<samp>shadowx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>shadowy</samp>&rsquo;</dt>
<dd><p>The x and y offsets for the text shadow position with respect to the
position of the text. They can be either positive or negative
values. Default value for both is &quot;0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>start_number</samp>&rsquo;</dt>
<dd><p>The starting frame number for the n/frame_num variable. The default value
is &quot;0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>tabsize</samp>&rsquo;</dt>
<dd><p>The size in number of spaces to use for rendering the tab.
Default value is 4.
</p>
</dd>
<dt> &lsquo;<samp>timecode</samp>&rsquo;</dt>
<dd><p>Set the initial timecode representation in &quot;hh:mm:ss[:;.]ff&quot;
format. It can be used with or without text parameter. <var>timecode_rate</var>
option must be specified.
</p>
</dd>
<dt> &lsquo;<samp>timecode_rate, rate, r</samp>&rsquo;</dt>
<dd><p>Set the timecode frame rate (timecode only).
</p>
</dd>
<dt> &lsquo;<samp>text</samp>&rsquo;</dt>
<dd><p>The text string to be drawn. The text must be a sequence of UTF-8
encoded characters.
This parameter is mandatory if no file is specified with the parameter
<var>textfile</var>.
</p>
</dd>
<dt> &lsquo;<samp>textfile</samp>&rsquo;</dt>
<dd><p>A text file containing text to be drawn. The text must be a sequence
of UTF-8 encoded characters.
</p>
<p>This parameter is mandatory if no text string is specified with the
parameter <var>text</var>.
</p>
<p>If both <var>text</var> and <var>textfile</var> are specified, an error is thrown.
</p>
</dd>
<dt> &lsquo;<samp>reload</samp>&rsquo;</dt>
<dd><p>If set to 1, the <var>textfile</var> will be reloaded before each frame.
Be sure to update it atomically, or it may be read partially, or even fail.
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>The expressions which specify the offsets where text will be drawn
within the video frame. They are relative to the top/left border of the
output image.
</p>
<p>The default value of <var>x</var> and <var>y</var> is &quot;0&quot;.
</p>
<p>See below for the list of accepted constants and functions.
</p></dd>
</dl>
<p>The parameters for <var>x</var> and <var>y</var> are expressions containing the
following constants and functions:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>dar</samp>&rsquo;</dt>
<dd><p>input display aspect ratio, it is the same as (<var>w</var> / <var>h</var>) * <var>sar</var>
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p>
</dd>
<dt> &lsquo;<samp>line_h, lh</samp>&rsquo;</dt>
<dd><p>the height of each text line
</p>
</dd>
<dt> &lsquo;<samp>main_h, h, H</samp>&rsquo;</dt>
<dd><p>the input height
</p>
</dd>
<dt> &lsquo;<samp>main_w, w, W</samp>&rsquo;</dt>
<dd><p>the input width
</p>
</dd>
<dt> &lsquo;<samp>max_glyph_a, ascent</samp>&rsquo;</dt>
<dd><p>the maximum distance from the baseline to the highest/upper grid
coordinate used to place a glyph outline point, for all the rendered
glyphs.
It is a positive value, due to the grid&rsquo;s orientation with the Y axis
upwards.
</p>
</dd>
<dt> &lsquo;<samp>max_glyph_d, descent</samp>&rsquo;</dt>
<dd><p>the maximum distance from the baseline to the lowest grid coordinate
used to place a glyph outline point, for all the rendered glyphs.
This is a negative value, due to the grid&rsquo;s orientation, with the Y axis
upwards.
</p>
</dd>
<dt> &lsquo;<samp>max_glyph_h</samp>&rsquo;</dt>
<dd><p>maximum glyph height, that is the maximum height for all the glyphs
contained in the rendered text, it is equivalent to <var>ascent</var> -
<var>descent</var>.
</p>
</dd>
<dt> &lsquo;<samp>max_glyph_w</samp>&rsquo;</dt>
<dd><p>maximum glyph width, that is the maximum width for all the glyphs
contained in the rendered text
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>the number of input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>rand(min, max)</samp>&rsquo;</dt>
<dd><p>return a random number included between <var>min</var> and <var>max</var>
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>input sample aspect ratio
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>timestamp expressed in seconds, NAN if the input timestamp is unknown
</p>
</dd>
<dt> &lsquo;<samp>text_h, th</samp>&rsquo;</dt>
<dd><p>the height of the rendered text
</p>
</dd>
<dt> &lsquo;<samp>text_w, tw</samp>&rsquo;</dt>
<dd><p>the width of the rendered text
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>the x and y offset coordinates where the text is drawn.
</p>
<p>These parameters allow the <var>x</var> and <var>y</var> expressions to refer
each other, so you can for example specify <code>y=x/dar</code>.
</p></dd>
</dl>
<p>If libavfilter was built with <code>--enable-fontconfig</code>, then
&lsquo;<samp>fontfile</samp>&rsquo; can be a fontconfig pattern or omitted.
</p>
<p><a name="drawtext_005fexpansion"></a>
</p><a name="Text-expansion"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Text-expansion">28.23.2 Text expansion</a></h3>
<p>If &lsquo;<samp>expansion</samp>&rsquo; is set to <code>strftime</code>,
the filter recognizes strftime() sequences in the provided text and
expands them accordingly. Check the documentation of strftime(). This
feature is deprecated.
</p>
<p>If &lsquo;<samp>expansion</samp>&rsquo; is set to <code>none</code>, the text is printed verbatim.
</p>
<p>If &lsquo;<samp>expansion</samp>&rsquo; is set to <code>normal</code> (which is the default),
the following expansion mechanism is used.
</p>
<p>The backslash character &rsquo;\&rsquo;, followed by any character, always expands to
the second character.
</p>
<p>Sequence of the form <code>%{...}</code> are expanded. The text between the
braces is a function name, possibly followed by arguments separated by &rsquo;:&rsquo;.
If the arguments contain special characters or delimiters (&rsquo;:&rsquo; or &rsquo;}&rsquo;),
they should be escaped.
</p>
<p>Note that they probably must also be escaped as the value for the
&lsquo;<samp>text</samp>&rsquo; option in the filter argument string and as the filter
argument in the filtergraph description, and possibly also for the shell,
that makes up to four levels of escaping; using a text file avoids these
problems.
</p>
<p>The following functions are available:
</p>
<dl compact="compact">
<dt> <code>expr, e</code></dt>
<dd><p>The expression evaluation result.
</p>
<p>It must take one argument specifying the expression to be evaluated,
which accepts the same constants and functions as the <var>x</var> and
<var>y</var> values. Note that not all constants should be used, for
example the text size is not known when evaluating the expression, so
the constants <var>text_w</var> and <var>text_h</var> will have an undefined
value.
</p>
</dd>
<dt> <code>gmtime</code></dt>
<dd><p>The time at which the filter is running, expressed in UTC.
It can accept an argument: a strftime() format string.
</p>
</dd>
<dt> <code>localtime</code></dt>
<dd><p>The time at which the filter is running, expressed in the local time zone.
It can accept an argument: a strftime() format string.
</p>
</dd>
<dt> <code>metadata</code></dt>
<dd><p>Frame metadata. It must take one argument specifying metadata key.
</p>
</dd>
<dt> <code>n, frame_num</code></dt>
<dd><p>The frame number, starting from 0.
</p>
</dd>
<dt> <code>pict_type</code></dt>
<dd><p>A 1 character description of the current picture type.
</p>
</dd>
<dt> <code>pts</code></dt>
<dd><p>The timestamp of the current frame, in seconds, with microsecond accuracy.
</p>
</dd>
</dl>
<a name="Examples-22"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-22">28.23.3 Examples</a></h3>
<ul>
<li>
Draw &quot;Test Text&quot; with font FreeSerif, using the default values for the
optional parameters.
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'&quot;
</pre></td></tr></table>
</li><li>
Draw &rsquo;Test Text&rsquo; with font FreeSerif of size 24 at position x=100
and y=50 (counting from the top-left corner of the screen), text is
yellow with a red box around it. Both the text and the box have an
opacity of 20%.
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
x=100: y=50: fontsize=24: fontcolor=yellow@0.2: box=1: boxcolor=red@0.2&quot;
</pre></td></tr></table>
<p>Note that the double quotes are not necessary if spaces are not used
within the parameter list.
</p>
</li><li>
Show the text at the center of the video frame:
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2&quot;
</pre></td></tr></table>
</li><li>
Show a text line sliding from right to left in the last row of the video
frame. The file &lsquo;<tt>LONG_LINE</tt>&rsquo; is assumed to contain a single line
with no newlines.
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t&quot;
</pre></td></tr></table>
</li><li>
Show the content of file &lsquo;<tt>CREDITS</tt>&rsquo; off the bottom of the frame and scroll up.
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t&quot;
</pre></td></tr></table>
</li><li>
Draw a single green letter &quot;g&quot;, at the center of the input video.
The glyph baseline is placed at half screen height.
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent&quot;
</pre></td></tr></table>
</li><li>
Show text for 1 second every 3 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext=&quot;fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'&quot;
</pre></td></tr></table>
</li><li>
Use fontconfig to set the font. Note that the colons need to be escaped.
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
</pre></td></tr></table>
</li><li>
Print the date of a real-time encoding (see strftime(3)):
<table><tr><td>&nbsp;</td><td><pre class="example">drawtext='fontfile=FreeSans.ttf:text=%{localtime:%a %b %d %Y}'
</pre></td></tr></table>
</li></ul>
<p>For more information about libfreetype, check:
<a href="http://www.freetype.org/">http://www.freetype.org/</a>.
</p>
<p>For more information about fontconfig, check:
<a href="http://freedesktop.org/software/fontconfig/fontconfig-user.html">http://freedesktop.org/software/fontconfig/fontconfig-user.html</a>.
</p>
<a name="edgedetect"></a>
<h2 class="section"><a href="ffplay-all.html#toc-edgedetect">28.24 edgedetect</a></h2>
<p>Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>low</samp>&rsquo;</dt>
<dt> &lsquo;<samp>high</samp>&rsquo;</dt>
<dd><p>Set low and high threshold values used by the Canny thresholding
algorithm.
</p>
<p>The high threshold selects the &quot;strong&quot; edge pixels, which are then
connected through 8-connectivity with the &quot;weak&quot; edge pixels selected
by the low threshold.
</p>
<p><var>low</var> and <var>high</var> threshold values must be chosen in the range
[0,1], and <var>low</var> should be lesser or equal to <var>high</var>.
</p>
<p>Default value for <var>low</var> is <code>20/255</code>, and default value for <var>high</var>
is <code>50/255</code>.
</p></dd>
</dl>
<p>Example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">edgedetect=low=0.1:high=0.4
</pre></td></tr></table>
<a name="extractplanes"></a>
<h2 class="section"><a href="ffplay-all.html#toc-extractplanes">28.25 extractplanes</a></h2>
<p>Extract color channel components from input video stream into
separate grayscale video streams.
</p>
<p>The filter accepts the following option:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>planes</samp>&rsquo;</dt>
<dd><p>Set plane(s) to extract.
</p>
<p>Available values for planes are:
</p><dl compact="compact">
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dt> &lsquo;<samp>u</samp>&rsquo;</dt>
<dt> &lsquo;<samp>v</samp>&rsquo;</dt>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dt> &lsquo;<samp>r</samp>&rsquo;</dt>
<dt> &lsquo;<samp>g</samp>&rsquo;</dt>
<dt> &lsquo;<samp>b</samp>&rsquo;</dt>
</dl>
<p>Choosing planes not available in the input will result in an error.
That means you cannot select <code>r</code>, <code>g</code>, <code>b</code> planes
with <code>y</code>, <code>u</code>, <code>v</code> planes at same time.
</p></dd>
</dl>
<a name="Examples-25"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-25">28.25.1 Examples</a></h3>
<ul>
<li>
Extract luma, u and v color channel component from input video frame
into 3 grayscale outputs:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi
</pre></td></tr></table>
</li></ul>
<a name="elbg"></a>
<h2 class="section"><a href="ffplay-all.html#toc-elbg">28.26 elbg</a></h2>
<p>Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
</p>
<p>For each input image, the filter will compute the optimal mapping from
the input to the output given the codebook length, that is the number
of distinct output colors.
</p>
<p>This filter accepts the following options.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>codebook_length, l</samp>&rsquo;</dt>
<dd><p>Set codebook length. The value must be a positive integer, and
represents the number of distinct output colors. Default value is 256.
</p>
</dd>
<dt> &lsquo;<samp>nb_steps, n</samp>&rsquo;</dt>
<dd><p>Set the maximum number of iterations to apply for computing the optimal
mapping. The higher the value the better the result and the higher the
computation time. Default value is 1.
</p>
</dd>
<dt> &lsquo;<samp>seed, s</samp>&rsquo;</dt>
<dd><p>Set a random seed, must be an integer included between 0 and
UINT32_MAX. If not specified, or if explicitly set to -1, the filter
will try to use a good random seed on a best effort basis.
</p></dd>
</dl>
<a name="fade"></a>
<h2 class="section"><a href="ffplay-all.html#toc-fade">28.27 fade</a></h2>
<p>Apply fade-in/out effect to input video.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>type, t</samp>&rsquo;</dt>
<dd><p>The effect type &ndash; can be either &quot;in&quot; for fade-in, or &quot;out&quot; for a fade-out
effect.
Default is <code>in</code>.
</p>
</dd>
<dt> &lsquo;<samp>start_frame, s</samp>&rsquo;</dt>
<dd><p>Specify the number of the start frame for starting to apply the fade
effect. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>nb_frames, n</samp>&rsquo;</dt>
<dd><p>The number of frames for which the fade effect has to last. At the end of the
fade-in effect the output video will have the same intensity as the input video,
at the end of the fade-out transition the output video will be filled with the
selected &lsquo;<samp>color</samp>&rsquo;.
Default is 25.
</p>
</dd>
<dt> &lsquo;<samp>alpha</samp>&rsquo;</dt>
<dd><p>If set to 1, fade only alpha channel, if one exists on the input.
Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>start_time, st</samp>&rsquo;</dt>
<dd><p>Specify the timestamp (in seconds) of the frame to start to apply the fade
effect. If both start_frame and start_time are specified, the fade will start at
whichever comes last. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>The number of seconds for which the fade effect has to last. At the end of the
fade-in effect the output video will have the same intensity as the input video,
at the end of the fade-out transition the output video will be filled with the
selected &lsquo;<samp>color</samp>&rsquo;.
If both duration and nb_frames are specified, duration is used. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>color, c</samp>&rsquo;</dt>
<dd><p>Specify the color of the fade. Default is &quot;black&quot;.
</p></dd>
</dl>
<a name="Examples-68"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-68">28.27.1 Examples</a></h3>
<ul>
<li>
Fade in first 30 frames of video:
<table><tr><td>&nbsp;</td><td><pre class="example">fade=in:0:30
</pre></td></tr></table>
<p>The command above is equivalent to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">fade=t=in:s=0:n=30
</pre></td></tr></table>
</li><li>
Fade out last 45 frames of a 200-frame video:
<table><tr><td>&nbsp;</td><td><pre class="example">fade=out:155:45
fade=type=out:start_frame=155:nb_frames=45
</pre></td></tr></table>
</li><li>
Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
<table><tr><td>&nbsp;</td><td><pre class="example">fade=in:0:25, fade=out:975:25
</pre></td></tr></table>
</li><li>
Make first 5 frames yellow, then fade in from frame 5-24:
<table><tr><td>&nbsp;</td><td><pre class="example">fade=in:5:20:color=yellow
</pre></td></tr></table>
</li><li>
Fade in alpha over first 25 frames of video:
<table><tr><td>&nbsp;</td><td><pre class="example">fade=in:0:25:alpha=1
</pre></td></tr></table>
</li><li>
Make first 5.5 seconds black, then fade in for 0.5 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">fade=t=in:st=5.5:d=0.5
</pre></td></tr></table>
</li></ul>
<a name="field"></a>
<h2 class="section"><a href="ffplay-all.html#toc-field">28.28 field</a></h2>
<p>Extract a single field from an interlaced image using stride
arithmetic to avoid wasting CPU time. The output frames are marked as
non-interlaced.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>type</samp>&rsquo;</dt>
<dd><p>Specify whether to extract the top (if the value is <code>0</code> or
<code>top</code>) or the bottom field (if the value is <code>1</code> or
<code>bottom</code>).
</p></dd>
</dl>
<a name="fieldmatch"></a>
<h2 class="section"><a href="ffplay-all.html#toc-fieldmatch">28.29 fieldmatch</a></h2>
<p>Field matching filter for inverse telecine. It is meant to reconstruct the
progressive frames from a telecined stream. The filter does not drop duplicated
frames, so to achieve a complete inverse telecine <code>fieldmatch</code> needs to be
followed by a decimation filter such as <a href="#decimate">decimate</a> in the filtergraph.
</p>
<p>The separation of the field matching and the decimation is notably motivated by
the possibility of inserting a de-interlacing filter fallback between the two.
If the source has mixed telecined and real interlaced content,
<code>fieldmatch</code> will not be able to match fields for the interlaced parts.
But these remaining combed frames will be marked as interlaced, and thus can be
de-interlaced by a later filter such as <a href="#yadif">yadif</a> before decimation.
</p>
<p>In addition to the various configuration options, <code>fieldmatch</code> can take an
optional second stream, activated through the &lsquo;<samp>ppsrc</samp>&rsquo; option. If
enabled, the frames reconstruction will be based on the fields and frames from
this second stream. This allows the first input to be pre-processed in order to
help the various algorithms of the filter, while keeping the output lossless
(assuming the fields are matched properly). Typically, a field-aware denoiser,
or brightness/contrast adjustments can help.
</p>
<p>Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
which <code>fieldmatch</code> is based on. While the semantic and usage are very
close, some behaviour and options names can differ.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>order</samp>&rsquo;</dt>
<dd><p>Specify the assumed field order of the input stream. Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>Auto detect parity (use FFmpeg&rsquo;s internal parity value).
</p></dd>
<dt> &lsquo;<samp>bff</samp>&rsquo;</dt>
<dd><p>Assume bottom field first.
</p></dd>
<dt> &lsquo;<samp>tff</samp>&rsquo;</dt>
<dd><p>Assume top field first.
</p></dd>
</dl>
<p>Note that it is sometimes recommended not to trust the parity announced by the
stream.
</p>
<p>Default value is <var>auto</var>.
</p>
</dd>
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set the matching mode or strategy to use. &lsquo;<samp>pc</samp>&rsquo; mode is the safest in the
sense that it won&rsquo;t risk creating jerkiness due to duplicate frames when
possible, but if there are bad edits or blended fields it will end up
outputting combed frames when a good match might actually exist. On the other
hand, &lsquo;<samp>pcn_ub</samp>&rsquo; mode is the most risky in terms of creating jerkiness,
but will almost always find a good frame if there is one. The other values are
all somewhere in between &lsquo;<samp>pc</samp>&rsquo; and &lsquo;<samp>pcn_ub</samp>&rsquo; in terms of risking
jerkiness and creating duplicate frames versus finding good matches in sections
with bad edits, orphaned fields, blended fields, etc.
</p>
<p>More details about p/c/n/u/b are available in <a href="#p_002fc_002fn_002fu_002fb-meaning">p/c/n/u/b meaning</a> section.
</p>
<p>Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>pc</samp>&rsquo;</dt>
<dd><p>2-way matching (p/c)
</p></dd>
<dt> &lsquo;<samp>pc_n</samp>&rsquo;</dt>
<dd><p>2-way matching, and trying 3rd match if still combed (p/c + n)
</p></dd>
<dt> &lsquo;<samp>pc_u</samp>&rsquo;</dt>
<dd><p>2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
</p></dd>
<dt> &lsquo;<samp>pc_n_ub</samp>&rsquo;</dt>
<dd><p>2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
still combed (p/c + n + u/b)
</p></dd>
<dt> &lsquo;<samp>pcn</samp>&rsquo;</dt>
<dd><p>3-way matching (p/c/n)
</p></dd>
<dt> &lsquo;<samp>pcn_ub</samp>&rsquo;</dt>
<dd><p>3-way matching, and trying 4th/5th matches if all 3 of the original matches are
detected as combed (p/c/n + u/b)
</p></dd>
</dl>
<p>The parenthesis at the end indicate the matches that would be used for that
mode assuming &lsquo;<samp>order</samp>&rsquo;=<var>tff</var> (and &lsquo;<samp>field</samp>&rsquo; on <var>auto</var> or
<var>top</var>).
</p>
<p>In terms of speed &lsquo;<samp>pc</samp>&rsquo; mode is by far the fastest and &lsquo;<samp>pcn_ub</samp>&rsquo; is
the slowest.
</p>
<p>Default value is <var>pc_n</var>.
</p>
</dd>
<dt> &lsquo;<samp>ppsrc</samp>&rsquo;</dt>
<dd><p>Mark the main input stream as a pre-processed input, and enable the secondary
input stream as the clean source to pick the fields from. See the filter
introduction for more details. It is similar to the &lsquo;<samp>clip2</samp>&rsquo; feature from
VFM/TFM.
</p>
<p>Default value is <code>0</code> (disabled).
</p>
</dd>
<dt> &lsquo;<samp>field</samp>&rsquo;</dt>
<dd><p>Set the field to match from. It is recommended to set this to the same value as
&lsquo;<samp>order</samp>&rsquo; unless you experience matching failures with that setting. In
certain circumstances changing the field that is used to match from can have a
large impact on matching performance. Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>Automatic (same value as &lsquo;<samp>order</samp>&rsquo;).
</p></dd>
<dt> &lsquo;<samp>bottom</samp>&rsquo;</dt>
<dd><p>Match from the bottom field.
</p></dd>
<dt> &lsquo;<samp>top</samp>&rsquo;</dt>
<dd><p>Match from the top field.
</p></dd>
</dl>
<p>Default value is <var>auto</var>.
</p>
</dd>
<dt> &lsquo;<samp>mchroma</samp>&rsquo;</dt>
<dd><p>Set whether or not chroma is included during the match comparisons. In most
cases it is recommended to leave this enabled. You should set this to <code>0</code>
only if your clip has bad chroma problems such as heavy rainbowing or other
artifacts. Setting this to <code>0</code> could also be used to speed things up at
the cost of some accuracy.
</p>
<p>Default value is <code>1</code>.
</p>
</dd>
<dt> &lsquo;<samp>y0</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y1</samp>&rsquo;</dt>
<dd><p>These define an exclusion band which excludes the lines between &lsquo;<samp>y0</samp>&rsquo; and
&lsquo;<samp>y1</samp>&rsquo; from being included in the field matching decision. An exclusion
band can be used to ignore subtitles, a logo, or other things that may
interfere with the matching. &lsquo;<samp>y0</samp>&rsquo; sets the starting scan line and
&lsquo;<samp>y1</samp>&rsquo; sets the ending line; all lines in between &lsquo;<samp>y0</samp>&rsquo; and
&lsquo;<samp>y1</samp>&rsquo; (including &lsquo;<samp>y0</samp>&rsquo; and &lsquo;<samp>y1</samp>&rsquo;) will be ignored. Setting
&lsquo;<samp>y0</samp>&rsquo; and &lsquo;<samp>y1</samp>&rsquo; to the same value will disable the feature.
&lsquo;<samp>y0</samp>&rsquo; and &lsquo;<samp>y1</samp>&rsquo; defaults to <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>scthresh</samp>&rsquo;</dt>
<dd><p>Set the scene change detection threshold as a percentage of maximum change on
the luma plane. Good values are in the <code>[8.0, 14.0]</code> range. Scene change
detection is only relevant in case &lsquo;<samp>combmatch</samp>&rsquo;=<var>sc</var>. The range for
&lsquo;<samp>scthresh</samp>&rsquo; is <code>[0.0, 100.0]</code>.
</p>
<p>Default value is <code>12.0</code>.
</p>
</dd>
<dt> &lsquo;<samp>combmatch</samp>&rsquo;</dt>
<dd><p>When &lsquo;<samp>combatch</samp>&rsquo; is not <var>none</var>, <code>fieldmatch</code> will take into
account the combed scores of matches when deciding what match to use as the
final match. Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>No final matching based on combed scores.
</p></dd>
<dt> &lsquo;<samp>sc</samp>&rsquo;</dt>
<dd><p>Combed scores are only used when a scene change is detected.
</p></dd>
<dt> &lsquo;<samp>full</samp>&rsquo;</dt>
<dd><p>Use combed scores all the time.
</p></dd>
</dl>
<p>Default is <var>sc</var>.
</p>
</dd>
<dt> &lsquo;<samp>combdbg</samp>&rsquo;</dt>
<dd><p>Force <code>fieldmatch</code> to calculate the combed metrics for certain matches and
print them. This setting is known as &lsquo;<samp>micout</samp>&rsquo; in TFM/VFM vocabulary.
Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>No forced calculation.
</p></dd>
<dt> &lsquo;<samp>pcn</samp>&rsquo;</dt>
<dd><p>Force p/c/n calculations.
</p></dd>
<dt> &lsquo;<samp>pcnub</samp>&rsquo;</dt>
<dd><p>Force p/c/n/u/b calculations.
</p></dd>
</dl>
<p>Default value is <var>none</var>.
</p>
</dd>
<dt> &lsquo;<samp>cthresh</samp>&rsquo;</dt>
<dd><p>This is the area combing threshold used for combed frame detection. This
essentially controls how &quot;strong&quot; or &quot;visible&quot; combing must be to be detected.
Larger values mean combing must be more visible and smaller values mean combing
can be less visible or strong and still be detected. Valid settings are from
<code>-1</code> (every pixel will be detected as combed) to <code>255</code> (no pixel will
be detected as combed). This is basically a pixel difference value. A good
range is <code>[8, 12]</code>.
</p>
<p>Default value is <code>9</code>.
</p>
</dd>
<dt> &lsquo;<samp>chroma</samp>&rsquo;</dt>
<dd><p>Sets whether or not chroma is considered in the combed frame decision. Only
disable this if your source has chroma problems (rainbowing, etc.) that are
causing problems for the combed frame detection with chroma enabled. Actually,
using &lsquo;<samp>chroma</samp>&rsquo;=<var>0</var> is usually more reliable, except for the case
where there is chroma only combing in the source.
</p>
<p>Default value is <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>blockx</samp>&rsquo;</dt>
<dt> &lsquo;<samp>blocky</samp>&rsquo;</dt>
<dd><p>Respectively set the x-axis and y-axis size of the window used during combed
frame detection. This has to do with the size of the area in which
&lsquo;<samp>combpel</samp>&rsquo; pixels are required to be detected as combed for a frame to be
declared combed. See the &lsquo;<samp>combpel</samp>&rsquo; parameter description for more info.
Possible values are any number that is a power of 2 starting at 4 and going up
to 512.
</p>
<p>Default value is <code>16</code>.
</p>
</dd>
<dt> &lsquo;<samp>combpel</samp>&rsquo;</dt>
<dd><p>The number of combed pixels inside any of the &lsquo;<samp>blocky</samp>&rsquo; by
&lsquo;<samp>blockx</samp>&rsquo; size blocks on the frame for the frame to be detected as
combed. While &lsquo;<samp>cthresh</samp>&rsquo; controls how &quot;visible&quot; the combing must be, this
setting controls &quot;how much&quot; combing there must be in any localized area (a
window defined by the &lsquo;<samp>blockx</samp>&rsquo; and &lsquo;<samp>blocky</samp>&rsquo; settings) on the
frame. Minimum value is <code>0</code> and maximum is <code>blocky x blockx</code> (at
which point no frames will ever be detected as combed). This setting is known
as &lsquo;<samp>MI</samp>&rsquo; in TFM/VFM vocabulary.
</p>
<p>Default value is <code>80</code>.
</p></dd>
</dl>
<p><a name="p_002fc_002fn_002fu_002fb-meaning"></a>
</p><a name="p_002fc_002fn_002fu_002fb-meaning-1"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-p_002fc_002fn_002fu_002fb-meaning-1">28.29.1 p/c/n/u/b meaning</a></h3>
<a name="p_002fc_002fn"></a>
<h4 class="subsubsection"><a href="ffplay-all.html#toc-p_002fc_002fn">28.29.1.1 p/c/n</a></h4>
<p>We assume the following telecined stream:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">Top fields: 1 2 2 3 4
Bottom fields: 1 2 3 4 4
</pre></td></tr></table>
<p>The numbers correspond to the progressive frame the fields relate to. Here, the
first two frames are progressive, the 3rd and 4th are combed, and so on.
</p>
<p>When <code>fieldmatch</code> is configured to run a matching from bottom
(&lsquo;<samp>field</samp>&rsquo;=<var>bottom</var>) this is how this input stream get transformed:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">Input stream:
T 1 2 2 3 4
B 1 2 3 4 4 &lt;-- matching reference
Matches: c c n n c
Output stream:
T 1 2 3 4 4
B 1 2 3 4 4
</pre></td></tr></table>
<p>As a result of the field matching, we can see that some frames get duplicated.
To perform a complete inverse telecine, you need to rely on a decimation filter
after this operation. See for instance the <a href="#decimate">decimate</a> filter.
</p>
<p>The same operation now matching from top fields (&lsquo;<samp>field</samp>&rsquo;=<var>top</var>)
looks like this:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">Input stream:
T 1 2 2 3 4 &lt;-- matching reference
B 1 2 3 4 4
Matches: c c p p c
Output stream:
T 1 2 2 3 4
B 1 2 2 3 4
</pre></td></tr></table>
<p>In these examples, we can see what <var>p</var>, <var>c</var> and <var>n</var> mean;
basically, they refer to the frame and field of the opposite parity:
</p>
<ul>
<li> <var>p</var> matches the field of the opposite parity in the previous frame
</li><li> <var>c</var> matches the field of the opposite parity in the current frame
</li><li> <var>n</var> matches the field of the opposite parity in the next frame
</li></ul>
<a name="u_002fb"></a>
<h4 class="subsubsection"><a href="ffplay-all.html#toc-u_002fb">28.29.1.2 u/b</a></h4>
<p>The <var>u</var> and <var>b</var> matching are a bit special in the sense that they match
from the opposite parity flag. In the following examples, we assume that we are
currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
&rsquo;x&rsquo; is placed above and below each matched fields.
</p>
<p>With bottom matching (&lsquo;<samp>field</samp>&rsquo;=<var>bottom</var>):
</p><table><tr><td>&nbsp;</td><td><pre class="example">Match: c p n b u
x x x x x
Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
x x x x x
Output frames:
2 1 2 2 2
2 2 2 1 3
</pre></td></tr></table>
<p>With top matching (&lsquo;<samp>field</samp>&rsquo;=<var>top</var>):
</p><table><tr><td>&nbsp;</td><td><pre class="example">Match: c p n b u
x x x x x
Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
x x x x x
Output frames:
2 2 2 1 2
2 1 3 2 2
</pre></td></tr></table>
<a name="Examples-57"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-57">28.29.2 Examples</a></h3>
<p>Simple IVTC of a top field first telecined stream:
</p><table><tr><td>&nbsp;</td><td><pre class="example">fieldmatch=order=tff:combmatch=none, decimate
</pre></td></tr></table>
<p>Advanced IVTC, with fallback on <a href="#yadif">yadif</a> for still combed frames:
</p><table><tr><td>&nbsp;</td><td><pre class="example">fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
</pre></td></tr></table>
<a name="fieldorder"></a>
<h2 class="section"><a href="ffplay-all.html#toc-fieldorder">28.30 fieldorder</a></h2>
<p>Transform the field order of the input video.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>order</samp>&rsquo;</dt>
<dd><p>Output field order. Valid values are <var>tff</var> for top field first or <var>bff</var>
for bottom field first.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>tff</samp>&rsquo;.
</p>
<p>Transformation is achieved by shifting the picture content up or down
by one line, and filling the remaining line with appropriate picture content.
This method is consistent with most broadcast field order converters.
</p>
<p>If the input video is not flagged as being interlaced, or it is already
flagged as being of the required output field order then this filter does
not alter the incoming video.
</p>
<p>This filter is very useful when converting to or from PAL DV material,
which is bottom field first.
</p>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.vob -vf &quot;fieldorder=bff&quot; out.dv
</pre></td></tr></table>
<a name="fifo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-fifo">28.31 fifo</a></h2>
<p>Buffer input images and send them when they are requested.
</p>
<p>This filter is mainly useful when auto-inserted by the libavfilter
framework.
</p>
<p>The filter does not take parameters.
</p>
<p><a name="format"></a>
</p><a name="format-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-format-1">28.32 format</a></h2>
<p>Convert the input video to one of the specified pixel formats.
Libavfilter will try to pick one that is supported for the input to
the next filter.
</p>
<p>This filter accepts the following parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>pix_fmts</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of pixel format names, for example
&quot;pix_fmts=yuv420p|monow|rgb24&quot;.
</p>
</dd>
</dl>
<a name="Examples-20"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-20">28.32.1 Examples</a></h3>
<ul>
<li>
Convert the input video to the format <var>yuv420p</var>
<table><tr><td>&nbsp;</td><td><pre class="example">format=pix_fmts=yuv420p
</pre></td></tr></table>
<p>Convert the input video to any of the formats in the list
</p><table><tr><td>&nbsp;</td><td><pre class="example">format=pix_fmts=yuv420p|yuv444p|yuv410p
</pre></td></tr></table>
</li></ul>
<p><a name="fps"></a>
</p><a name="fps-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-fps-1">28.33 fps</a></h2>
<p>Convert the video to specified constant frame rate by duplicating or dropping
frames as necessary.
</p>
<p>This filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>fps</samp>&rsquo;</dt>
<dd><p>Desired output frame rate. The default is <code>25</code>.
</p>
</dd>
<dt> &lsquo;<samp>round</samp>&rsquo;</dt>
<dd><p>Rounding method.
</p>
<p>Possible values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>zero</samp>&rsquo;</dt>
<dd><p>zero round towards 0
</p></dd>
<dt> &lsquo;<samp>inf</samp>&rsquo;</dt>
<dd><p>round away from 0
</p></dd>
<dt> &lsquo;<samp>down</samp>&rsquo;</dt>
<dd><p>round towards -infinity
</p></dd>
<dt> &lsquo;<samp>up</samp>&rsquo;</dt>
<dd><p>round towards +infinity
</p></dd>
<dt> &lsquo;<samp>near</samp>&rsquo;</dt>
<dd><p>round to nearest
</p></dd>
</dl>
<p>The default is <code>near</code>.
</p>
</dd>
<dt> &lsquo;<samp>start_time</samp>&rsquo;</dt>
<dd><p>Assume the first PTS should be the given value, in seconds. This allows for
padding/trimming at the start of stream. By default, no assumption is made
about the first frame&rsquo;s expected PTS, so no padding or trimming is done.
For example, this could be set to 0 to pad the beginning with duplicates of
the first frame if a video stream starts after the audio stream or to trim any
frames with a negative PTS.
</p>
</dd>
</dl>
<p>Alternatively, the options can be specified as a flat string:
<var>fps</var>[:<var>round</var>].
</p>
<p>See also the <a href="#setpts">setpts</a> filter.
</p>
<a name="Examples-32"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-32">28.33.1 Examples</a></h3>
<ul>
<li>
A typical usage in order to set the fps to 25:
<table><tr><td>&nbsp;</td><td><pre class="example">fps=fps=25
</pre></td></tr></table>
</li><li>
Sets the fps to 24, using abbreviation and rounding method to round to nearest:
<table><tr><td>&nbsp;</td><td><pre class="example">fps=fps=film:round=near
</pre></td></tr></table>
</li></ul>
<a name="framepack"></a>
<h2 class="section"><a href="ffplay-all.html#toc-framepack">28.34 framepack</a></h2>
<p>Pack two different video streams into a stereoscopic video, setting proper
metadata on supported codecs. The two views should have the same size and
framerate and processing will stop when the shorter video ends. Please note
that you may conveniently adjust view properties with the <a href="#scale">scale</a> and
<a href="#fps">fps</a> filters.
</p>
<p>This filter accepts the following named parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>format</samp>&rsquo;</dt>
<dd><p>Desired packing format. Supported values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>sbs</samp>&rsquo;</dt>
<dd><p>Views are next to each other (default).
</p>
</dd>
<dt> &lsquo;<samp>tab</samp>&rsquo;</dt>
<dd><p>Views are on top of each other.
</p>
</dd>
<dt> &lsquo;<samp>lines</samp>&rsquo;</dt>
<dd><p>Views are packed by line.
</p>
</dd>
<dt> &lsquo;<samp>columns</samp>&rsquo;</dt>
<dd><p>Views are eacked by column.
</p>
</dd>
<dt> &lsquo;<samp>frameseq</samp>&rsquo;</dt>
<dd><p>Views are temporally interleaved.
</p>
</dd>
</dl>
</dd>
</dl>
<p>Some examples follow:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example"># Convert left and right views into a frame sequential video.
ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
# Convert views into a side-by-side video with the same output resolution as the input.
ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
</pre></td></tr></table>
<a name="framestep"></a>
<h2 class="section"><a href="ffplay-all.html#toc-framestep">28.35 framestep</a></h2>
<p>Select one frame every N-th frame.
</p>
<p>This filter accepts the following option:
</p><dl compact="compact">
<dt> &lsquo;<samp>step</samp>&rsquo;</dt>
<dd><p>Select frame after every <code>step</code> frames.
Allowed values are positive integers higher than 0. Default value is <code>1</code>.
</p></dd>
</dl>
<p><a name="frei0r"></a>
</p><a name="frei0r-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-frei0r-1">28.36 frei0r</a></h2>
<p>Apply a frei0r effect to the input video.
</p>
<p>To enable compilation of this filter you need to install the frei0r
header and configure FFmpeg with <code>--enable-frei0r</code>.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filter_name</samp>&rsquo;</dt>
<dd><p>The name to the frei0r effect to load. If the environment variable
<code>FREI0R_PATH</code> is defined, the frei0r effect is searched in each one of the
directories specified by the colon separated list in <code>FREIOR_PATH</code>,
otherwise in the standard frei0r paths, which are in this order:
&lsquo;<tt>HOME/.frei0r-1/lib/</tt>&rsquo;, &lsquo;<tt>/usr/local/lib/frei0r-1/</tt>&rsquo;,
&lsquo;<tt>/usr/lib/frei0r-1/</tt>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>filter_params</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of parameters to pass to the frei0r effect.
</p>
</dd>
</dl>
<p>A frei0r effect parameter can be a boolean (whose values are specified
with &quot;y&quot; and &quot;n&quot;), a double, a color (specified by the syntax
<var>R</var>/<var>G</var>/<var>B</var>, (<var>R</var>, <var>G</var>, and <var>B</var> being float
numbers from 0.0 to 1.0) or by a color description specified in the &quot;Color&quot;
section in the ffmpeg-utils manual), a position (specified by the syntax <var>X</var>/<var>Y</var>,
<var>X</var> and <var>Y</var> being float numbers) and a string.
</p>
<p>The number and kind of parameters depend on the loaded effect. If an
effect parameter is not specified the default value is set.
</p>
<a name="Examples-6"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-6">28.36.1 Examples</a></h3>
<ul>
<li>
Apply the distort0r effect, set the first two double parameters:
<table><tr><td>&nbsp;</td><td><pre class="example">frei0r=filter_name=distort0r:filter_params=0.5|0.01
</pre></td></tr></table>
</li><li>
Apply the colordistance effect, take a color as first parameter:
<table><tr><td>&nbsp;</td><td><pre class="example">frei0r=colordistance:0.2/0.3/0.4
frei0r=colordistance:violet
frei0r=colordistance:0x112233
</pre></td></tr></table>
</li><li>
Apply the perspective effect, specify the top left and top right image
positions:
<table><tr><td>&nbsp;</td><td><pre class="example">frei0r=perspective:0.2/0.2|0.8/0.2
</pre></td></tr></table>
</li></ul>
<p>For more information see:
<a href="http://frei0r.dyne.org">http://frei0r.dyne.org</a>
</p>
<a name="geq"></a>
<h2 class="section"><a href="ffplay-all.html#toc-geq">28.37 geq</a></h2>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>lum_expr, lum</samp>&rsquo;</dt>
<dd><p>Set the luminance expression.
</p></dd>
<dt> &lsquo;<samp>cb_expr, cb</samp>&rsquo;</dt>
<dd><p>Set the chrominance blue expression.
</p></dd>
<dt> &lsquo;<samp>cr_expr, cr</samp>&rsquo;</dt>
<dd><p>Set the chrominance red expression.
</p></dd>
<dt> &lsquo;<samp>alpha_expr, a</samp>&rsquo;</dt>
<dd><p>Set the alpha expression.
</p></dd>
<dt> &lsquo;<samp>red_expr, r</samp>&rsquo;</dt>
<dd><p>Set the red expression.
</p></dd>
<dt> &lsquo;<samp>green_expr, g</samp>&rsquo;</dt>
<dd><p>Set the green expression.
</p></dd>
<dt> &lsquo;<samp>blue_expr, b</samp>&rsquo;</dt>
<dd><p>Set the blue expression.
</p></dd>
</dl>
<p>The colorspace is selected according to the specified options. If one
of the &lsquo;<samp>lum_expr</samp>&rsquo;, &lsquo;<samp>cb_expr</samp>&rsquo;, or &lsquo;<samp>cr_expr</samp>&rsquo;
options is specified, the filter will automatically select a YCbCr
colorspace. If one of the &lsquo;<samp>red_expr</samp>&rsquo;, &lsquo;<samp>green_expr</samp>&rsquo;, or
&lsquo;<samp>blue_expr</samp>&rsquo; options is specified, it will select an RGB
colorspace.
</p>
<p>If one of the chrominance expression is not defined, it falls back on the other
one. If no alpha expression is specified it will evaluate to opaque value.
If none of chrominance expressions are specified, they will evaluate
to the luminance expression.
</p>
<p>The expressions can use the following variables and functions:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>N</samp>&rsquo;</dt>
<dd><p>The sequential number of the filtered frame, starting from <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>X</samp>&rsquo;</dt>
<dt> &lsquo;<samp>Y</samp>&rsquo;</dt>
<dd><p>The coordinates of the current sample.
</p>
</dd>
<dt> &lsquo;<samp>W</samp>&rsquo;</dt>
<dt> &lsquo;<samp>H</samp>&rsquo;</dt>
<dd><p>The width and height of the image.
</p>
</dd>
<dt> &lsquo;<samp>SW</samp>&rsquo;</dt>
<dt> &lsquo;<samp>SH</samp>&rsquo;</dt>
<dd><p>Width and height scale depending on the currently filtered plane. It is the
ratio between the corresponding luma plane number of pixels and the current
plane ones. E.g. for YUV4:2:0 the values are <code>1,1</code> for the luma plane, and
<code>0.5,0.5</code> for chroma planes.
</p>
</dd>
<dt> &lsquo;<samp>T</samp>&rsquo;</dt>
<dd><p>Time of the current frame, expressed in seconds.
</p>
</dd>
<dt> &lsquo;<samp>p(x, y)</samp>&rsquo;</dt>
<dd><p>Return the value of the pixel at location (<var>x</var>,<var>y</var>) of the current
plane.
</p>
</dd>
<dt> &lsquo;<samp>lum(x, y)</samp>&rsquo;</dt>
<dd><p>Return the value of the pixel at location (<var>x</var>,<var>y</var>) of the luminance
plane.
</p>
</dd>
<dt> &lsquo;<samp>cb(x, y)</samp>&rsquo;</dt>
<dd><p>Return the value of the pixel at location (<var>x</var>,<var>y</var>) of the
blue-difference chroma plane. Return 0 if there is no such plane.
</p>
</dd>
<dt> &lsquo;<samp>cr(x, y)</samp>&rsquo;</dt>
<dd><p>Return the value of the pixel at location (<var>x</var>,<var>y</var>) of the
red-difference chroma plane. Return 0 if there is no such plane.
</p>
</dd>
<dt> &lsquo;<samp>r(x, y)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>g(x, y)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>b(x, y)</samp>&rsquo;</dt>
<dd><p>Return the value of the pixel at location (<var>x</var>,<var>y</var>) of the
red/green/blue component. Return 0 if there is no such component.
</p>
</dd>
<dt> &lsquo;<samp>alpha(x, y)</samp>&rsquo;</dt>
<dd><p>Return the value of the pixel at location (<var>x</var>,<var>y</var>) of the alpha
plane. Return 0 if there is no such plane.
</p></dd>
</dl>
<p>For functions, if <var>x</var> and <var>y</var> are outside the area, the value will be
automatically clipped to the closer edge.
</p>
<a name="Examples-1"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-1">28.37.1 Examples</a></h3>
<ul>
<li>
Flip the image horizontally:
<table><tr><td>&nbsp;</td><td><pre class="example">geq=p(W-X\,Y)
</pre></td></tr></table>
</li><li>
Generate a bidimensional sine wave, with angle <code>PI/3</code> and a
wavelength of 100 pixels:
<table><tr><td>&nbsp;</td><td><pre class="example">geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
</pre></td></tr></table>
</li><li>
Generate a fancy enigmatic moving light:
<table><tr><td>&nbsp;</td><td><pre class="example">nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
</pre></td></tr></table>
</li><li>
Generate a quick emboss effect:
<table><tr><td>&nbsp;</td><td><pre class="example">format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
</pre></td></tr></table>
</li><li>
Modify RGB components depending on pixel position:
<table><tr><td>&nbsp;</td><td><pre class="example">geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
</pre></td></tr></table>
</li></ul>
<a name="gradfun"></a>
<h2 class="section"><a href="ffplay-all.html#toc-gradfun">28.38 gradfun</a></h2>
<p>Fix the banding artifacts that are sometimes introduced into nearly flat
regions by truncation to 8bit color depth.
Interpolate the gradients that should go where the bands are, and
dither them.
</p>
<p>This filter is designed for playback only. Do not use it prior to
lossy compression, because compression tends to lose the dither and
bring back the bands.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>strength</samp>&rsquo;</dt>
<dd><p>The maximum amount by which the filter will change any one pixel. Also the
threshold for detecting nearly flat regions. Acceptable values range from .51 to
64, default value is 1.2, out-of-range values will be clipped to the valid
range.
</p>
</dd>
<dt> &lsquo;<samp>radius</samp>&rsquo;</dt>
<dd><p>The neighborhood to fit the gradient to. A larger radius makes for smoother
gradients, but also prevents the filter from modifying the pixels near detailed
regions. Acceptable values are 8-32, default value is 16, out-of-range values
will be clipped to the valid range.
</p>
</dd>
</dl>
<p>Alternatively, the options can be specified as a flat string:
<var>strength</var>[:<var>radius</var>]
</p>
<a name="Examples-27"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-27">28.38.1 Examples</a></h3>
<ul>
<li>
Apply the filter with a <code>3.5</code> strength and radius of <code>8</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">gradfun=3.5:8
</pre></td></tr></table>
</li><li>
Specify radius, omitting the strength (which will fall-back to the default
value):
<table><tr><td>&nbsp;</td><td><pre class="example">gradfun=radius=8
</pre></td></tr></table>
</li></ul>
<p><a name="haldclut"></a>
</p><a name="haldclut-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-haldclut-1">28.39 haldclut</a></h2>
<p>Apply a Hald CLUT to a video stream.
</p>
<p>First input is the video stream to process, and second one is the Hald CLUT.
The Hald CLUT input can be a simple picture or a complete video stream.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>shortest</samp>&rsquo;</dt>
<dd><p>Force termination when the shortest input terminates. Default is <code>0</code>.
</p></dd>
<dt> &lsquo;<samp>repeatlast</samp>&rsquo;</dt>
<dd><p>Continue applying the last CLUT after the end of the stream. A value of
<code>0</code> disable the filter after the last frame of the CLUT is reached.
Default is <code>1</code>.
</p></dd>
</dl>
<p><code>haldclut</code> also has the same interpolation options as <a href="#lut3d">lut3d</a> (both
filters share the same internals).
</p>
<p>More information about the Hald CLUT can be found on Eskil Steenberg&rsquo;s website
(Hald CLUT author) at <a href="http://www.quelsolaar.com/technology/clut.html">http://www.quelsolaar.com/technology/clut.html</a>.
</p>
<a name="Workflow-examples"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Workflow-examples">28.39.1 Workflow examples</a></h3>
<a name="Hald-CLUT-video-stream"></a>
<h4 class="subsubsection"><a href="ffplay-all.html#toc-Hald-CLUT-video-stream">28.39.1.1 Hald CLUT video stream</a></h4>
<p>Generate an identity Hald CLUT stream altered with various effects:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f lavfi -i <a href="#haldclutsrc">haldclutsrc</a>=8 -vf &quot;hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process&quot; -t 10 -c:v ffv1 clut.nut
</pre></td></tr></table>
<p>Note: make sure you use a lossless codec.
</p>
<p>Then use it with <code>haldclut</code> to apply it on some random stream:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
</pre></td></tr></table>
<p>The Hald CLUT will be applied to the 10 first seconds (duration of
&lsquo;<tt>clut.nut</tt>&rsquo;), then the latest picture of that CLUT stream will be applied
to the remaining frames of the <code>mandelbrot</code> stream.
</p>
<a name="Hald-CLUT-with-preview"></a>
<h4 class="subsubsection"><a href="ffplay-all.html#toc-Hald-CLUT-with-preview">28.39.1.2 Hald CLUT with preview</a></h4>
<p>A Hald CLUT is supposed to be a squared image of <code>Level*Level*Level</code> by
<code>Level*Level*Level</code> pixels. For a given Hald CLUT, FFmpeg will select the
biggest possible square starting at the top left of the picture. The remaining
padding pixels (bottom or right) will be ignored. This area can be used to add
a preview of the Hald CLUT.
</p>
<p>Typically, the following generated Hald CLUT will be supported by the
<code>haldclut</code> filter:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -f lavfi -i <a href="#haldclutsrc">haldclutsrc</a>=8 -vf &quot;
pad=iw+320 [padded_clut];
smptebars=s=320x256, split [a][b];
[padded_clut][a] overlay=W-320:h, curves=color_negative [main];
[main][b] overlay=W-320&quot; -frames:v 1 clut.png
</pre></td></tr></table>
<p>It contains the original and a preview of the effect of the CLUT: SMPTE color
bars are displayed on the right-top, and below the same color bars processed by
the color changes.
</p>
<p>Then, the effect of this Hald CLUT can be visualized with:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay input.mkv -vf &quot;movie=clut.png, [in] haldclut&quot;
</pre></td></tr></table>
<a name="hflip"></a>
<h2 class="section"><a href="ffplay-all.html#toc-hflip">28.40 hflip</a></h2>
<p>Flip the input video horizontally.
</p>
<p>For example to horizontally flip the input video with <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.avi -vf &quot;hflip&quot; out.avi
</pre></td></tr></table>
<a name="histeq"></a>
<h2 class="section"><a href="ffplay-all.html#toc-histeq">28.41 histeq</a></h2>
<p>This filter applies a global color histogram equalization on a
per-frame basis.
</p>
<p>It can be used to correct video that has a compressed range of pixel
intensities. The filter redistributes the pixel intensities to
equalize their distribution across the intensity range. It may be
viewed as an &quot;automatically adjusting contrast filter&quot;. This filter is
useful only for correcting degraded or poorly captured source
video.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>strength</samp>&rsquo;</dt>
<dd><p>Determine the amount of equalization to be applied. As the strength
is reduced, the distribution of pixel intensities more-and-more
approaches that of the input frame. The value must be a float number
in the range [0,1] and defaults to 0.200.
</p>
</dd>
<dt> &lsquo;<samp>intensity</samp>&rsquo;</dt>
<dd><p>Set the maximum intensity that can generated and scale the output
values appropriately. The strength should be set as desired and then
the intensity can be limited if needed to avoid washing-out. The value
must be a float number in the range [0,1] and defaults to 0.210.
</p>
</dd>
<dt> &lsquo;<samp>antibanding</samp>&rsquo;</dt>
<dd><p>Set the antibanding level. If enabled the filter will randomly vary
the luminance of output pixels by a small amount to avoid banding of
the histogram. Possible values are <code>none</code>, <code>weak</code> or
<code>strong</code>. It defaults to <code>none</code>.
</p></dd>
</dl>
<a name="histogram"></a>
<h2 class="section"><a href="ffplay-all.html#toc-histogram">28.42 histogram</a></h2>
<p>Compute and draw a color distribution histogram for the input video.
</p>
<p>The computed histogram is a representation of the color component
distribution in an image.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set histogram mode.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>levels</samp>&rsquo;</dt>
<dd><p>Standard histogram that displays the color components distribution in an
image. Displays color graph for each color component. Shows distribution of
the Y, U, V, A or R, G, B components, depending on input format, in the
current frame. Below each graph a color component scale meter is shown.
</p>
</dd>
<dt> &lsquo;<samp>color</samp>&rsquo;</dt>
<dd><p>Displays chroma values (U/V color placement) in a two dimensional
graph (which is called a vectorscope). The brighter a pixel in the
vectorscope, the more pixels of the input frame correspond to that pixel
(i.e., more pixels have this chroma value). The V component is displayed on
the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
side being V = 255. The U component is displayed on the vertical (Y) axis,
with the top representing U = 0 and the bottom representing U = 255.
</p>
<p>The position of a white pixel in the graph corresponds to the chroma value of
a pixel of the input clip. The graph can therefore be used to read the hue
(color flavor) and the saturation (the dominance of the hue in the color). As
the hue of a color changes, it moves around the square. At the center of the
square the saturation is zero, which means that the corresponding pixel has no
color. If the amount of a specific color is increased (while leaving the other
colors unchanged) the saturation increases, and the indicator moves towards
the edge of the square.
</p>
</dd>
<dt> &lsquo;<samp>color2</samp>&rsquo;</dt>
<dd><p>Chroma values in vectorscope, similar as <code>color</code> but actual chroma values
are displayed.
</p>
</dd>
<dt> &lsquo;<samp>waveform</samp>&rsquo;</dt>
<dd><p>Per row/column color component graph. In row mode, the graph on the left side
represents color component value 0 and the right side represents value = 255.
In column mode, the top side represents color component value = 0 and bottom
side represents value = 255.
</p></dd>
</dl>
<p>Default value is <code>levels</code>.
</p>
</dd>
<dt> &lsquo;<samp>level_height</samp>&rsquo;</dt>
<dd><p>Set height of level in <code>levels</code>. Default value is <code>200</code>.
Allowed range is [50, 2048].
</p>
</dd>
<dt> &lsquo;<samp>scale_height</samp>&rsquo;</dt>
<dd><p>Set height of color scale in <code>levels</code>. Default value is <code>12</code>.
Allowed range is [0, 40].
</p>
</dd>
<dt> &lsquo;<samp>step</samp>&rsquo;</dt>
<dd><p>Set step for <code>waveform</code> mode. Smaller values are useful to find out how
many values of the same luminance are distributed across input rows/columns.
Default value is <code>10</code>. Allowed range is [1, 255].
</p>
</dd>
<dt> &lsquo;<samp>waveform_mode</samp>&rsquo;</dt>
<dd><p>Set mode for <code>waveform</code>. Can be either <code>row</code>, or <code>column</code>.
Default is <code>row</code>.
</p>
</dd>
<dt> &lsquo;<samp>waveform_mirror</samp>&rsquo;</dt>
<dd><p>Set mirroring mode for <code>waveform</code>. <code>0</code> means unmirrored, <code>1</code>
means mirrored. In mirrored mode, higher values will be represented on the left
side for <code>row</code> mode and at the top for <code>column</code> mode. Default is
<code>0</code> (unmirrored).
</p>
</dd>
<dt> &lsquo;<samp>display_mode</samp>&rsquo;</dt>
<dd><p>Set display mode for <code>waveform</code> and <code>levels</code>.
It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>parade</samp>&rsquo;</dt>
<dd><p>Display separate graph for the color components side by side in
<code>row</code> waveform mode or one below the other in <code>column</code> waveform mode
for <code>waveform</code> histogram mode. For <code>levels</code> histogram mode,
per color component graphs are placed below each other.
</p>
<p>Using this display mode in <code>waveform</code> histogram mode makes it easy to
spot color casts in the highlights and shadows of an image, by comparing the
contours of the top and the bottom graphs of each waveform. Since whites,
grays, and blacks are characterized by exactly equal amounts of red, green,
and blue, neutral areas of the picture should display three waveforms of
roughly equal width/height. If not, the correction is easy to perform by
making level adjustments the three waveforms.
</p>
</dd>
<dt> &lsquo;<samp>overlay</samp>&rsquo;</dt>
<dd><p>Presents information identical to that in the <code>parade</code>, except
that the graphs representing color components are superimposed directly
over one another.
</p>
<p>This display mode in <code>waveform</code> histogram mode makes it easier to spot
relative differences or similarities in overlapping areas of the color
components that are supposed to be identical, such as neutral whites, grays,
or blacks.
</p></dd>
</dl>
<p>Default is <code>parade</code>.
</p>
</dd>
<dt> &lsquo;<samp>levels_mode</samp>&rsquo;</dt>
<dd><p>Set mode for <code>levels</code>. Can be either <code>linear</code>, or <code>logarithmic</code>.
Default is <code>linear</code>.
</p></dd>
</dl>
<a name="Examples-3"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-3">28.42.1 Examples</a></h3>
<ul>
<li>
Calculate and draw histogram:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -i input -vf histogram
</pre></td></tr></table>
</li></ul>
<p><a name="hqdn3d"></a>
</p><a name="hqdn3d-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-hqdn3d-1">28.43 hqdn3d</a></h2>
<p>High precision/quality 3d denoise filter. This filter aims to reduce
image noise producing smooth images and making still images really
still. It should enhance compressibility.
</p>
<p>It accepts the following optional parameters:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_spatial</samp>&rsquo;</dt>
<dd><p>a non-negative float number which specifies spatial luma strength,
defaults to 4.0
</p>
</dd>
<dt> &lsquo;<samp>chroma_spatial</samp>&rsquo;</dt>
<dd><p>a non-negative float number which specifies spatial chroma strength,
defaults to 3.0*<var>luma_spatial</var>/4.0
</p>
</dd>
<dt> &lsquo;<samp>luma_tmp</samp>&rsquo;</dt>
<dd><p>a float number which specifies luma temporal strength, defaults to
6.0*<var>luma_spatial</var>/4.0
</p>
</dd>
<dt> &lsquo;<samp>chroma_tmp</samp>&rsquo;</dt>
<dd><p>a float number which specifies chroma temporal strength, defaults to
<var>luma_tmp</var>*<var>chroma_spatial</var>/<var>luma_spatial</var>
</p></dd>
</dl>
<a name="hue"></a>
<h2 class="section"><a href="ffplay-all.html#toc-hue">28.44 hue</a></h2>
<p>Modify the hue and/or the saturation of the input.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>Specify the hue angle as a number of degrees. It accepts an expression,
and defaults to &quot;0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>Specify the saturation in the [-10,10] range. It accepts an expression and
defaults to &quot;1&quot;.
</p>
</dd>
<dt> &lsquo;<samp>H</samp>&rsquo;</dt>
<dd><p>Specify the hue angle as a number of radians. It accepts an
expression, and defaults to &quot;0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>b</samp>&rsquo;</dt>
<dd><p>Specify the brightness in the [-10,10] range. It accepts an expression and
defaults to &quot;0&quot;.
</p></dd>
</dl>
<p>&lsquo;<samp>h</samp>&rsquo; and &lsquo;<samp>H</samp>&rsquo; are mutually exclusive, and can&rsquo;t be
specified at the same time.
</p>
<p>The &lsquo;<samp>b</samp>&rsquo;, &lsquo;<samp>h</samp>&rsquo;, &lsquo;<samp>H</samp>&rsquo; and &lsquo;<samp>s</samp>&rsquo; option values are
expressions containing the following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>frame count of the input frame starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dd><p>presentation timestamp of the input frame expressed in time base units
</p>
</dd>
<dt> &lsquo;<samp>r</samp>&rsquo;</dt>
<dd><p>frame rate of the input video, NAN if the input frame rate is unknown
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>timestamp expressed in seconds, NAN if the input timestamp is unknown
</p>
</dd>
<dt> &lsquo;<samp>tb</samp>&rsquo;</dt>
<dd><p>time base of the input video
</p></dd>
</dl>
<a name="Examples-24"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-24">28.44.1 Examples</a></h3>
<ul>
<li>
Set the hue to 90 degrees and the saturation to 1.0:
<table><tr><td>&nbsp;</td><td><pre class="example">hue=h=90:s=1
</pre></td></tr></table>
</li><li>
Same command but expressing the hue in radians:
<table><tr><td>&nbsp;</td><td><pre class="example">hue=H=PI/2:s=1
</pre></td></tr></table>
</li><li>
Rotate hue and make the saturation swing between 0
and 2 over a period of 1 second:
<table><tr><td>&nbsp;</td><td><pre class="example">hue=&quot;H=2*PI*t: s=sin(2*PI*t)+1&quot;
</pre></td></tr></table>
</li><li>
Apply a 3 seconds saturation fade-in effect starting at 0:
<table><tr><td>&nbsp;</td><td><pre class="example">hue=&quot;s=min(t/3\,1)&quot;
</pre></td></tr></table>
<p>The general fade-in expression can be written as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">hue=&quot;s=min(0\, max((t-START)/DURATION\, 1))&quot;
</pre></td></tr></table>
</li><li>
Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">hue=&quot;s=max(0\, min(1\, (8-t)/3))&quot;
</pre></td></tr></table>
<p>The general fade-out expression can be written as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">hue=&quot;s=max(0\, min(1\, (START+DURATION-t)/DURATION))&quot;
</pre></td></tr></table>
</li></ul>
<a name="Commands-1"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands-1">28.44.2 Commands</a></h3>
<p>This filter supports the following commands:
</p><dl compact="compact">
<dt> &lsquo;<samp>b</samp>&rsquo;</dt>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dt> &lsquo;<samp>H</samp>&rsquo;</dt>
<dd><p>Modify the hue and/or the saturation and/or brightness of the input video.
The command accepts the same syntax of the corresponding option.
</p>
<p>If the specified expression is not valid, it is kept at its current
value.
</p></dd>
</dl>
<a name="idet"></a>
<h2 class="section"><a href="ffplay-all.html#toc-idet">28.45 idet</a></h2>
<p>Detect video interlacing type.
</p>
<p>This filter tries to detect if the input is interlaced or progressive,
top or bottom field first.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>intl_thres</samp>&rsquo;</dt>
<dd><p>Set interlacing threshold.
</p></dd>
<dt> &lsquo;<samp>prog_thres</samp>&rsquo;</dt>
<dd><p>Set progressive threshold.
</p></dd>
</dl>
<a name="il"></a>
<h2 class="section"><a href="ffplay-all.html#toc-il">28.46 il</a></h2>
<p>Deinterleave or interleave fields.
</p>
<p>This filter allows one to process interlaced images fields without
deinterlacing them. Deinterleaving splits the input frame into 2
fields (so called half pictures). Odd lines are moved to the top
half of the output image, even lines to the bottom half.
You can process (filter) them independently and then re-interleave them.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_mode, l</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_mode, c</samp>&rsquo;</dt>
<dt> &lsquo;<samp>alpha_mode, a</samp>&rsquo;</dt>
<dd><p>Available values for <var>luma_mode</var>, <var>chroma_mode</var> and
<var>alpha_mode</var> are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>Do nothing.
</p>
</dd>
<dt> &lsquo;<samp>deinterleave, d</samp>&rsquo;</dt>
<dd><p>Deinterleave fields, placing one above the other.
</p>
</dd>
<dt> &lsquo;<samp>interleave, i</samp>&rsquo;</dt>
<dd><p>Interleave fields. Reverse the effect of deinterleaving.
</p></dd>
</dl>
<p>Default value is <code>none</code>.
</p>
</dd>
<dt> &lsquo;<samp>luma_swap, ls</samp>&rsquo;</dt>
<dt> &lsquo;<samp>chroma_swap, cs</samp>&rsquo;</dt>
<dt> &lsquo;<samp>alpha_swap, as</samp>&rsquo;</dt>
<dd><p>Swap luma/chroma/alpha fields. Exchange even &amp; odd lines. Default value is <code>0</code>.
</p></dd>
</dl>
<a name="interlace"></a>
<h2 class="section"><a href="ffplay-all.html#toc-interlace">28.47 interlace</a></h2>
<p>Simple interlacing filter from progressive contents. This interleaves upper (or
lower) lines from odd frames with lower (or upper) lines from even frames,
halving the frame rate and preserving image height. A vertical lowpass filter
is always applied in order to avoid twitter effects and reduce moiré patterns.
</p>
<table><tr><td>&nbsp;</td><td><pre class="example"> Original Original New Frame
Frame 'j' Frame 'j+1' (tff)
========== =========== ==================
Line 0 --------------------&gt; Frame 'j' Line 0
Line 1 Line 1 ----&gt; Frame 'j+1' Line 1
Line 2 ---------------------&gt; Frame 'j' Line 2
Line 3 Line 3 ----&gt; Frame 'j+1' Line 3
... ... ...
New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
</pre></td></tr></table>
<p>It accepts the following optional parameters:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>scan</samp>&rsquo;</dt>
<dd><p>determines whether the interlaced frame is taken from the even (tff - default)
or odd (bff) lines of the progressive frame.
</p></dd>
</dl>
<a name="kerndeint"></a>
<h2 class="section"><a href="ffplay-all.html#toc-kerndeint">28.48 kerndeint</a></h2>
<p>Deinterlace input video by applying Donald Graft&rsquo;s adaptive kernel
deinterling. Work on interlaced parts of a video to produce
progressive frames.
</p>
<p>The description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>thresh</samp>&rsquo;</dt>
<dd><p>Set the threshold which affects the filter&rsquo;s tolerance when
determining if a pixel line must be processed. It must be an integer
in the range [0,255] and defaults to 10. A value of 0 will result in
applying the process on every pixels.
</p>
</dd>
<dt> &lsquo;<samp>map</samp>&rsquo;</dt>
<dd><p>Paint pixels exceeding the threshold value to white if set to 1.
Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>order</samp>&rsquo;</dt>
<dd><p>Set the fields order. Swap fields if set to 1, leave fields alone if
0. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>sharp</samp>&rsquo;</dt>
<dd><p>Enable additional sharpening if set to 1. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>twoway</samp>&rsquo;</dt>
<dd><p>Enable twoway sharpening if set to 1. Default is 0.
</p></dd>
</dl>
<a name="Examples-81"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-81">28.48.1 Examples</a></h3>
<ul>
<li>
Apply default values:
<table><tr><td>&nbsp;</td><td><pre class="example">kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
</pre></td></tr></table>
</li><li>
Enable additional sharpening:
<table><tr><td>&nbsp;</td><td><pre class="example">kerndeint=sharp=1
</pre></td></tr></table>
</li><li>
Paint processed pixels in white:
<table><tr><td>&nbsp;</td><td><pre class="example">kerndeint=map=1
</pre></td></tr></table>
</li></ul>
<p><a name="lut3d"></a>
</p><a name="lut3d-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-lut3d-1">28.49 lut3d</a></h2>
<p>Apply a 3D LUT to an input video.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>file</samp>&rsquo;</dt>
<dd><p>Set the 3D LUT file name.
</p>
<p>Currently supported formats:
</p><dl compact="compact">
<dt> &lsquo;<samp>3dl</samp>&rsquo;</dt>
<dd><p>AfterEffects
</p></dd>
<dt> &lsquo;<samp>cube</samp>&rsquo;</dt>
<dd><p>Iridas
</p></dd>
<dt> &lsquo;<samp>dat</samp>&rsquo;</dt>
<dd><p>DaVinci
</p></dd>
<dt> &lsquo;<samp>m3d</samp>&rsquo;</dt>
<dd><p>Pandora
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>interp</samp>&rsquo;</dt>
<dd><p>Select interpolation mode.
</p>
<p>Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>nearest</samp>&rsquo;</dt>
<dd><p>Use values from the nearest defined point.
</p></dd>
<dt> &lsquo;<samp>trilinear</samp>&rsquo;</dt>
<dd><p>Interpolate values using the 8 points defining a cube.
</p></dd>
<dt> &lsquo;<samp>tetrahedral</samp>&rsquo;</dt>
<dd><p>Interpolate values using a tetrahedron.
</p></dd>
</dl>
</dd>
</dl>
<a name="lut_002c-lutrgb_002c-lutyuv"></a>
<h2 class="section"><a href="ffplay-all.html#toc-lut_002c-lutrgb_002c-lutyuv">28.50 lut, lutrgb, lutyuv</a></h2>
<p>Compute a look-up table for binding each pixel component input value
to an output value, and apply it to input video.
</p>
<p><var>lutyuv</var> applies a lookup table to a YUV input video, <var>lutrgb</var>
to an RGB input video.
</p>
<p>These filters accept the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>c0</samp>&rsquo;</dt>
<dd><p>set first pixel component expression
</p></dd>
<dt> &lsquo;<samp>c1</samp>&rsquo;</dt>
<dd><p>set second pixel component expression
</p></dd>
<dt> &lsquo;<samp>c2</samp>&rsquo;</dt>
<dd><p>set third pixel component expression
</p></dd>
<dt> &lsquo;<samp>c3</samp>&rsquo;</dt>
<dd><p>set fourth pixel component expression, corresponds to the alpha component
</p>
</dd>
<dt> &lsquo;<samp>r</samp>&rsquo;</dt>
<dd><p>set red component expression
</p></dd>
<dt> &lsquo;<samp>g</samp>&rsquo;</dt>
<dd><p>set green component expression
</p></dd>
<dt> &lsquo;<samp>b</samp>&rsquo;</dt>
<dd><p>set blue component expression
</p></dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>alpha component expression
</p>
</dd>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>set Y/luminance component expression
</p></dd>
<dt> &lsquo;<samp>u</samp>&rsquo;</dt>
<dd><p>set U/Cb component expression
</p></dd>
<dt> &lsquo;<samp>v</samp>&rsquo;</dt>
<dd><p>set V/Cr component expression
</p></dd>
</dl>
<p>Each of them specifies the expression to use for computing the lookup table for
the corresponding pixel component values.
</p>
<p>The exact component associated to each of the <var>c*</var> options depends on the
format in input.
</p>
<p>The <var>lut</var> filter requires either YUV or RGB pixel formats in input,
<var>lutrgb</var> requires RGB pixel formats in input, and <var>lutyuv</var> requires YUV.
</p>
<p>The expressions can contain the following constants and functions:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>the input width and height
</p>
</dd>
<dt> &lsquo;<samp>val</samp>&rsquo;</dt>
<dd><p>input value for the pixel component
</p>
</dd>
<dt> &lsquo;<samp>clipval</samp>&rsquo;</dt>
<dd><p>the input value clipped in the <var>minval</var>-<var>maxval</var> range
</p>
</dd>
<dt> &lsquo;<samp>maxval</samp>&rsquo;</dt>
<dd><p>maximum value for the pixel component
</p>
</dd>
<dt> &lsquo;<samp>minval</samp>&rsquo;</dt>
<dd><p>minimum value for the pixel component
</p>
</dd>
<dt> &lsquo;<samp>negval</samp>&rsquo;</dt>
<dd><p>the negated value for the pixel component value clipped in the
<var>minval</var>-<var>maxval</var> range , it corresponds to the expression
&quot;maxval-clipval+minval&quot;
</p>
</dd>
<dt> &lsquo;<samp>clip(val)</samp>&rsquo;</dt>
<dd><p>the computed value in <var>val</var> clipped in the
<var>minval</var>-<var>maxval</var> range
</p>
</dd>
<dt> &lsquo;<samp>gammaval(gamma)</samp>&rsquo;</dt>
<dd><p>the computed gamma correction value of the pixel component value
clipped in the <var>minval</var>-<var>maxval</var> range, corresponds to the
expression
&quot;pow((clipval-minval)/(maxval-minval)\,<var>gamma</var>)*(maxval-minval)+minval&quot;
</p>
</dd>
</dl>
<p>All expressions default to &quot;val&quot;.
</p>
<a name="Examples-48"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-48">28.50.1 Examples</a></h3>
<ul>
<li>
Negate input video:
<table><tr><td>&nbsp;</td><td><pre class="example">lutrgb=&quot;r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val&quot;
lutyuv=&quot;y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val&quot;
</pre></td></tr></table>
<p>The above is the same as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">lutrgb=&quot;r=negval:g=negval:b=negval&quot;
lutyuv=&quot;y=negval:u=negval:v=negval&quot;
</pre></td></tr></table>
</li><li>
Negate luminance:
<table><tr><td>&nbsp;</td><td><pre class="example">lutyuv=y=negval
</pre></td></tr></table>
</li><li>
Remove chroma components, turns the video into a graytone image:
<table><tr><td>&nbsp;</td><td><pre class="example">lutyuv=&quot;u=128:v=128&quot;
</pre></td></tr></table>
</li><li>
Apply a luma burning effect:
<table><tr><td>&nbsp;</td><td><pre class="example">lutyuv=&quot;y=2*val&quot;
</pre></td></tr></table>
</li><li>
Remove green and blue components:
<table><tr><td>&nbsp;</td><td><pre class="example">lutrgb=&quot;g=0:b=0&quot;
</pre></td></tr></table>
</li><li>
Set a constant alpha channel value on input:
<table><tr><td>&nbsp;</td><td><pre class="example">format=rgba,lutrgb=a=&quot;maxval-minval/2&quot;
</pre></td></tr></table>
</li><li>
Correct luminance gamma by a 0.5 factor:
<table><tr><td>&nbsp;</td><td><pre class="example">lutyuv=y=gammaval(0.5)
</pre></td></tr></table>
</li><li>
Discard least significant bits of luma:
<table><tr><td>&nbsp;</td><td><pre class="example">lutyuv=y='bitand(val, 128+64+32)'
</pre></td></tr></table>
</li></ul>
<a name="mergeplanes"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mergeplanes">28.51 mergeplanes</a></h2>
<p>Merge color channel components from several video streams.
</p>
<p>The filter accepts up to 4 input streams, and merge selected input
planes to the output video.
</p>
<p>This filter accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>mapping</samp>&rsquo;</dt>
<dd><p>Set input to output plane mapping. Default is <code>0</code>.
</p>
<p>The mappings is specified as a bitmap. It should be specified as a
hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. &rsquo;Aa&rsquo; describes the
mapping for the first plane of the output stream. &rsquo;A&rsquo; sets the number of
the input stream to use (from 0 to 3), and &rsquo;a&rsquo; the plane number of the
corresponding input to use (from 0 to 3). The rest of the mappings is
similar, &rsquo;Bb&rsquo; describes the mapping for the output stream second
plane, &rsquo;Cc&rsquo; describes the mapping for the output stream third plane and
&rsquo;Dd&rsquo; describes the mapping for the output stream fourth plane.
</p>
</dd>
<dt> &lsquo;<samp>format</samp>&rsquo;</dt>
<dd><p>Set output pixel format. Default is <code>yuva444p</code>.
</p></dd>
</dl>
<a name="Examples-34"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-34">28.51.1 Examples</a></h3>
<ul>
<li>
Merge three gray video streams of same width and height into single video stream:
<table><tr><td>&nbsp;</td><td><pre class="example">[a0][a1][a2]mergeplanes=0x001020:yuv444p
</pre></td></tr></table>
</li><li>
Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
<table><tr><td>&nbsp;</td><td><pre class="example">[a0][a1]mergeplanes=0x00010210:yuva444p
</pre></td></tr></table>
</li><li>
Swap Y and A plane in yuva444p stream:
<table><tr><td>&nbsp;</td><td><pre class="example">format=yuva444p,mergeplanes=0x03010200:yuva444p
</pre></td></tr></table>
</li><li>
Swap U and V plane in yuv420p stream:
<table><tr><td>&nbsp;</td><td><pre class="example">format=yuv420p,mergeplanes=0x000201:yuv420p
</pre></td></tr></table>
</li><li>
Cast a rgb24 clip to yuv444p:
<table><tr><td>&nbsp;</td><td><pre class="example">format=rgb24,mergeplanes=0x000102:yuv444p
</pre></td></tr></table>
</li></ul>
<a name="mcdeint"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mcdeint">28.52 mcdeint</a></h2>
<p>Apply motion-compensation deinterlacing.
</p>
<p>It needs one field per frame as input and must thus be used together
with yadif=1/3 or equivalent.
</p>
<p>This filter accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set the deinterlacing mode.
</p>
<p>It accepts one of the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>fast</samp>&rsquo;</dt>
<dt> &lsquo;<samp>medium</samp>&rsquo;</dt>
<dt> &lsquo;<samp>slow</samp>&rsquo;</dt>
<dd><p>use iterative motion estimation
</p></dd>
<dt> &lsquo;<samp>extra_slow</samp>&rsquo;</dt>
<dd><p>like &lsquo;<samp>slow</samp>&rsquo;, but use multiple reference frames.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>fast</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>parity</samp>&rsquo;</dt>
<dd><p>Set the picture field parity assumed for the input video. It must be
one of the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>0, tff</samp>&rsquo;</dt>
<dd><p>assume top field first
</p></dd>
<dt> &lsquo;<samp>1, bff</samp>&rsquo;</dt>
<dd><p>assume bottom field first
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>bff</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>qp</samp>&rsquo;</dt>
<dd><p>Set per-block quantization parameter (QP) used by the internal
encoder.
</p>
<p>Higher values should result in a smoother motion vector field but less
optimal individual vectors. Default value is 1.
</p></dd>
</dl>
<a name="mp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mp">28.53 mp</a></h2>
<p>Apply an MPlayer filter to the input video.
</p>
<p>This filter provides a wrapper around some of the filters of
MPlayer/MEncoder.
</p>
<p>This wrapper is considered experimental. Some of the wrapped filters
may not work properly and we may drop support for them, as they will
be implemented natively into FFmpeg. Thus you should avoid
depending on them when writing portable scripts.
</p>
<p>The filter accepts the parameters:
<var>filter_name</var>[:=]<var>filter_params</var>
</p>
<p><var>filter_name</var> is the name of a supported MPlayer filter,
<var>filter_params</var> is a string containing the parameters accepted by
the named filter.
</p>
<p>The list of the currently supported filters follows:
</p><dl compact="compact">
<dt> <var>eq2</var></dt>
<dt> <var>eq</var></dt>
<dt> <var>fspp</var></dt>
<dt> <var>ilpack</var></dt>
<dt> <var>pp7</var></dt>
<dt> <var>softpulldown</var></dt>
<dt> <var>uspp</var></dt>
</dl>
<p>The parameter syntax and behavior for the listed filters are the same
of the corresponding MPlayer filters. For detailed instructions check
the &quot;VIDEO FILTERS&quot; section in the MPlayer manual.
</p>
<a name="Examples-58"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-58">28.53.1 Examples</a></h3>
<ul>
<li>
Adjust gamma, brightness, contrast:
<table><tr><td>&nbsp;</td><td><pre class="example">mp=eq2=1.0:2:0.5
</pre></td></tr></table>
</li></ul>
<p>See also mplayer(1), <a href="http://www.mplayerhq.hu/">http://www.mplayerhq.hu/</a>.
</p>
<a name="mpdecimate"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mpdecimate">28.54 mpdecimate</a></h2>
<p>Drop frames that do not differ greatly from the previous frame in
order to reduce frame rate.
</p>
<p>The main use of this filter is for very-low-bitrate encoding
(e.g. streaming over dialup modem), but it could in theory be used for
fixing movies that were inverse-telecined incorrectly.
</p>
<p>A description of the accepted options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>max</samp>&rsquo;</dt>
<dd><p>Set the maximum number of consecutive frames which can be dropped (if
positive), or the minimum interval between dropped frames (if
negative). If the value is 0, the frame is dropped unregarding the
number of previous sequentially dropped frames.
</p>
<p>Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>hi</samp>&rsquo;</dt>
<dt> &lsquo;<samp>lo</samp>&rsquo;</dt>
<dt> &lsquo;<samp>frac</samp>&rsquo;</dt>
<dd><p>Set the dropping threshold values.
</p>
<p>Values for &lsquo;<samp>hi</samp>&rsquo; and &lsquo;<samp>lo</samp>&rsquo; are for 8x8 pixel blocks and
represent actual pixel value differences, so a threshold of 64
corresponds to 1 unit of difference for each pixel, or the same spread
out differently over the block.
</p>
<p>A frame is a candidate for dropping if no 8x8 blocks differ by more
than a threshold of &lsquo;<samp>hi</samp>&rsquo;, and if no more than &lsquo;<samp>frac</samp>&rsquo; blocks (1
meaning the whole image) differ by more than a threshold of &lsquo;<samp>lo</samp>&rsquo;.
</p>
<p>Default value for &lsquo;<samp>hi</samp>&rsquo; is 64*12, default value for &lsquo;<samp>lo</samp>&rsquo; is
64*5, and default value for &lsquo;<samp>frac</samp>&rsquo; is 0.33.
</p></dd>
</dl>
<a name="negate"></a>
<h2 class="section"><a href="ffplay-all.html#toc-negate">28.55 negate</a></h2>
<p>Negate input video.
</p>
<p>This filter accepts an integer in input, if non-zero it negates the
alpha component (if available). The default value in input is 0.
</p>
<a name="noformat"></a>
<h2 class="section"><a href="ffplay-all.html#toc-noformat">28.56 noformat</a></h2>
<p>Force libavfilter not to use any of the specified pixel formats for the
input to the next filter.
</p>
<p>This filter accepts the following parameters:
</p><dl compact="compact">
<dt> &lsquo;<samp>pix_fmts</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of pixel format names, for example
&quot;pix_fmts=yuv420p|monow|rgb24&quot;.
</p>
</dd>
</dl>
<a name="Examples-39"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-39">28.56.1 Examples</a></h3>
<ul>
<li>
Force libavfilter to use a format different from <var>yuv420p</var> for the
input to the vflip filter:
<table><tr><td>&nbsp;</td><td><pre class="example">noformat=pix_fmts=yuv420p,vflip
</pre></td></tr></table>
</li><li>
Convert the input video to any of the formats not contained in the list:
<table><tr><td>&nbsp;</td><td><pre class="example">noformat=yuv420p|yuv444p|yuv410p
</pre></td></tr></table>
</li></ul>
<a name="noise"></a>
<h2 class="section"><a href="ffplay-all.html#toc-noise">28.57 noise</a></h2>
<p>Add noise on video input frame.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>all_seed</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c0_seed</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c1_seed</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c2_seed</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c3_seed</samp>&rsquo;</dt>
<dd><p>Set noise seed for specific pixel component or all pixel components in case
of <var>all_seed</var>. Default value is <code>123457</code>.
</p>
</dd>
<dt> &lsquo;<samp>all_strength, alls</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c0_strength, c0s</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c1_strength, c1s</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c2_strength, c2s</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c3_strength, c3s</samp>&rsquo;</dt>
<dd><p>Set noise strength for specific pixel component or all pixel components in case
<var>all_strength</var>. Default value is <code>0</code>. Allowed range is [0, 100].
</p>
</dd>
<dt> &lsquo;<samp>all_flags, allf</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c0_flags, c0f</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c1_flags, c1f</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c2_flags, c2f</samp>&rsquo;</dt>
<dt> &lsquo;<samp>c3_flags, c3f</samp>&rsquo;</dt>
<dd><p>Set pixel component flags or set flags for all components if <var>all_flags</var>.
Available values for component flags are:
</p><dl compact="compact">
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>averaged temporal noise (smoother)
</p></dd>
<dt> &lsquo;<samp>p</samp>&rsquo;</dt>
<dd><p>mix random noise with a (semi)regular pattern
</p></dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>temporal noise (noise pattern changes between frames)
</p></dd>
<dt> &lsquo;<samp>u</samp>&rsquo;</dt>
<dd><p>uniform noise (gaussian otherwise)
</p></dd>
</dl>
</dd>
</dl>
<a name="Examples-12"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-12">28.57.1 Examples</a></h3>
<p>Add temporal and uniform noise to input video:
</p><table><tr><td>&nbsp;</td><td><pre class="example">noise=alls=20:allf=t+u
</pre></td></tr></table>
<a name="null"></a>
<h2 class="section"><a href="ffplay-all.html#toc-null">28.58 null</a></h2>
<p>Pass the video source unchanged to the output.
</p>
<a name="ocv"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ocv">28.59 ocv</a></h2>
<p>Apply video transform using libopencv.
</p>
<p>To enable this filter install libopencv library and headers and
configure FFmpeg with <code>--enable-libopencv</code>.
</p>
<p>This filter accepts the following parameters:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filter_name</samp>&rsquo;</dt>
<dd><p>The name of the libopencv filter to apply.
</p>
</dd>
<dt> &lsquo;<samp>filter_params</samp>&rsquo;</dt>
<dd><p>The parameters to pass to the libopencv filter. If not specified the default
values are assumed.
</p>
</dd>
</dl>
<p>Refer to the official libopencv documentation for more precise
information:
<a href="http://opencv.willowgarage.com/documentation/c/image_filtering.html">http://opencv.willowgarage.com/documentation/c/image_filtering.html</a>
</p>
<p>Follows the list of supported libopencv filters.
</p>
<p><a name="dilate"></a>
</p><a name="dilate-1"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-dilate-1">28.59.1 dilate</a></h3>
<p>Dilate an image by using a specific structuring element.
This filter corresponds to the libopencv function <code>cvDilate</code>.
</p>
<p>It accepts the parameters: <var>struct_el</var>|<var>nb_iterations</var>.
</p>
<p><var>struct_el</var> represents a structuring element, and has the syntax:
<var>cols</var>x<var>rows</var>+<var>anchor_x</var>x<var>anchor_y</var>/<var>shape</var>
</p>
<p><var>cols</var> and <var>rows</var> represent the number of columns and rows of
the structuring element, <var>anchor_x</var> and <var>anchor_y</var> the anchor
point, and <var>shape</var> the shape for the structuring element, and
can be one of the values &quot;rect&quot;, &quot;cross&quot;, &quot;ellipse&quot;, &quot;custom&quot;.
</p>
<p>If the value for <var>shape</var> is &quot;custom&quot;, it must be followed by a
string of the form &quot;=<var>filename</var>&quot;. The file with name
<var>filename</var> is assumed to represent a binary image, with each
printable character corresponding to a bright pixel. When a custom
<var>shape</var> is used, <var>cols</var> and <var>rows</var> are ignored, the number
or columns and rows of the read file are assumed instead.
</p>
<p>The default value for <var>struct_el</var> is &quot;3x3+0x0/rect&quot;.
</p>
<p><var>nb_iterations</var> specifies the number of times the transform is
applied to the image, and defaults to 1.
</p>
<p>Follow some example:
</p><table><tr><td>&nbsp;</td><td><pre class="example"># use the default values
ocv=dilate
# dilate using a structuring element with a 5x5 cross, iterate two times
ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
# read the shape from the file diamond.shape, iterate two times
# the file diamond.shape may contain a pattern of characters like this:
# *
# ***
# *****
# ***
# *
# the specified cols and rows are ignored (but not the anchor point coordinates)
ocv=dilate:0x0+2x2/custom=diamond.shape|2
</pre></td></tr></table>
<a name="erode"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-erode">28.59.2 erode</a></h3>
<p>Erode an image by using a specific structuring element.
This filter corresponds to the libopencv function <code>cvErode</code>.
</p>
<p>The filter accepts the parameters: <var>struct_el</var>:<var>nb_iterations</var>,
with the same syntax and semantics as the <a href="#dilate">dilate</a> filter.
</p>
<a name="smooth"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-smooth">28.59.3 smooth</a></h3>
<p>Smooth the input video.
</p>
<p>The filter takes the following parameters:
<var>type</var>|<var>param1</var>|<var>param2</var>|<var>param3</var>|<var>param4</var>.
</p>
<p><var>type</var> is the type of smooth filter to apply, and can be one of
the following values: &quot;blur&quot;, &quot;blur_no_scale&quot;, &quot;median&quot;, &quot;gaussian&quot;,
&quot;bilateral&quot;. The default value is &quot;gaussian&quot;.
</p>
<p><var>param1</var>, <var>param2</var>, <var>param3</var>, and <var>param4</var> are
parameters whose meanings depend on smooth type. <var>param1</var> and
<var>param2</var> accept integer positive values or 0, <var>param3</var> and
<var>param4</var> accept float values.
</p>
<p>The default value for <var>param1</var> is 3, the default value for the
other parameters is 0.
</p>
<p>These parameters correspond to the parameters assigned to the
libopencv function <code>cvSmooth</code>.
</p>
<p><a name="overlay"></a>
</p><a name="overlay-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-overlay-1">28.60 overlay</a></h2>
<p>Overlay one video on top of another.
</p>
<p>It takes two inputs and one output, the first input is the &quot;main&quot;
video on which the second input is overlayed.
</p>
<p>This filter accepts the following parameters:
</p>
<p>A description of the accepted options follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>Set the expression for the x and y coordinates of the overlayed video
on the main video. Default value is &quot;0&quot; for both expressions. In case
the expression is invalid, it is set to a huge value (meaning that the
overlay will not be displayed within the output visible area).
</p>
</dd>
<dt> &lsquo;<samp>eof_action</samp>&rsquo;</dt>
<dd><p>The action to take when EOF is encountered on the secondary input, accepts one
of the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>repeat</samp>&rsquo;</dt>
<dd><p>repeat the last frame (the default)
</p></dd>
<dt> &lsquo;<samp>endall</samp>&rsquo;</dt>
<dd><p>end both streams
</p></dd>
<dt> &lsquo;<samp>pass</samp>&rsquo;</dt>
<dd><p>pass through the main input
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>eval</samp>&rsquo;</dt>
<dd><p>Set when the expressions for &lsquo;<samp>x</samp>&rsquo;, and &lsquo;<samp>y</samp>&rsquo; are evaluated.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>init</samp>&rsquo;</dt>
<dd><p>only evaluate expressions once during the filter initialization or
when a command is processed
</p>
</dd>
<dt> &lsquo;<samp>frame</samp>&rsquo;</dt>
<dd><p>evaluate expressions for each incoming frame
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>frame</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>shortest</samp>&rsquo;</dt>
<dd><p>If set to 1, force the output to terminate when the shortest input
terminates. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>format</samp>&rsquo;</dt>
<dd><p>Set the format for the output video.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>yuv420</samp>&rsquo;</dt>
<dd><p>force YUV420 output
</p>
</dd>
<dt> &lsquo;<samp>yuv422</samp>&rsquo;</dt>
<dd><p>force YUV422 output
</p>
</dd>
<dt> &lsquo;<samp>yuv444</samp>&rsquo;</dt>
<dd><p>force YUV444 output
</p>
</dd>
<dt> &lsquo;<samp>rgb</samp>&rsquo;</dt>
<dd><p>force RGB output
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>yuv420</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>rgb <em>(deprecated)</em></samp>&rsquo;</dt>
<dd><p>If set to 1, force the filter to accept inputs in the RGB
color space. Default value is 0. This option is deprecated, use
&lsquo;<samp>format</samp>&rsquo; instead.
</p>
</dd>
<dt> &lsquo;<samp>repeatlast</samp>&rsquo;</dt>
<dd><p>If set to 1, force the filter to draw the last overlay frame over the
main input until the end of the stream. A value of 0 disables this
behavior. Default value is 1.
</p></dd>
</dl>
<p>The &lsquo;<samp>x</samp>&rsquo;, and &lsquo;<samp>y</samp>&rsquo; expressions can contain the following
parameters.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>main_w, W</samp>&rsquo;</dt>
<dt> &lsquo;<samp>main_h, H</samp>&rsquo;</dt>
<dd><p>main input width and height
</p>
</dd>
<dt> &lsquo;<samp>overlay_w, w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>overlay_h, h</samp>&rsquo;</dt>
<dd><p>overlay input width and height
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>the computed values for <var>x</var> and <var>y</var>. They are evaluated for
each new frame.
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values of the output
format. For example for the pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and
<var>vsub</var> is 1.
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>the number of input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>the position in the file of the input frame, NAN if unknown
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>timestamp expressed in seconds, NAN if the input timestamp is unknown
</p>
</dd>
</dl>
<p>Note that the <var>n</var>, <var>pos</var>, <var>t</var> variables are available only
when evaluation is done <em>per frame</em>, and will evaluate to NAN
when &lsquo;<samp>eval</samp>&rsquo; is set to &lsquo;<samp>init</samp>&rsquo;.
</p>
<p>Be aware that frames are taken from each input video in timestamp
order, hence, if their initial timestamps differ, it is a good idea
to pass the two inputs through a <var>setpts=PTS-STARTPTS</var> filter to
have them begin in the same zero timestamp, as it does the example for
the <var>movie</var> filter.
</p>
<p>You can chain together more overlays but you should test the
efficiency of such approach.
</p>
<a name="Commands-2"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands-2">28.60.1 Commands</a></h3>
<p>This filter supports the following commands:
</p><dl compact="compact">
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>Modify the x and y of the overlay input.
The command accepts the same syntax of the corresponding option.
</p>
<p>If the specified expression is not valid, it is kept at its current
value.
</p></dd>
</dl>
<a name="Examples-11"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-11">28.60.2 Examples</a></h3>
<ul>
<li>
Draw the overlay at 10 pixels from the bottom right corner of the main
video:
<table><tr><td>&nbsp;</td><td><pre class="example">overlay=main_w-overlay_w-10:main_h-overlay_h-10
</pre></td></tr></table>
<p>Using named options the example above becomes:
</p><table><tr><td>&nbsp;</td><td><pre class="example">overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
</pre></td></tr></table>
</li><li>
Insert a transparent PNG logo in the bottom left corner of the input,
using the <code>ffmpeg</code> tool with the <code>-filter_complex</code> option:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
</pre></td></tr></table>
</li><li>
Insert 2 different transparent PNG logos (second logo on bottom
right corner) using the <code>ffmpeg</code> tool:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
</pre></td></tr></table>
</li><li>
Add a transparent color layer on top of the main video, <code>WxH</code>
must specify the size of the main input to the overlay filter:
<table><tr><td>&nbsp;</td><td><pre class="example">color=color=red@.3:size=WxH [over]; [in][over] overlay [out]
</pre></td></tr></table>
</li><li>
Play an original video and a filtered version (here with the deshake
filter) side by side using the <code>ffplay</code> tool:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
</pre></td></tr></table>
<p>The above command is the same as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
</pre></td></tr></table>
</li><li>
Make a sliding overlay appearing from the left to the right top part of the
screen starting since time 2:
<table><tr><td>&nbsp;</td><td><pre class="example">overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
</pre></td></tr></table>
</li><li>
Compose output by putting two input videos side to side:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i left.avi -i right.avi -filter_complex &quot;
nullsrc=size=200x100 [background];
[0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
[1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
[background][left] overlay=shortest=1 [background+left];
[background+left][right] overlay=shortest=1:x=100 [left+right]
&quot;
</pre></td></tr></table>
</li><li>
mask 10-20 seconds of a video by applying the delogo filter to a section
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
-vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
masked.avi
</pre></td></tr></table>
</li><li>
Chain several overlays in cascade:
<table><tr><td>&nbsp;</td><td><pre class="example">nullsrc=s=200x200 [bg];
testsrc=s=100x100, split=4 [in0][in1][in2][in3];
[in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
[in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
[in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
[in3] null, [mid2] overlay=100:100 [out0]
</pre></td></tr></table>
</li></ul>
<a name="owdenoise"></a>
<h2 class="section"><a href="ffplay-all.html#toc-owdenoise">28.61 owdenoise</a></h2>
<p>Apply Overcomplete Wavelet denoiser.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>depth</samp>&rsquo;</dt>
<dd><p>Set depth.
</p>
<p>Larger depth values will denoise lower frequency components more, but
slow down filtering.
</p>
<p>Must be an int in the range 8-16, default is <code>8</code>.
</p>
</dd>
<dt> &lsquo;<samp>luma_strength, ls</samp>&rsquo;</dt>
<dd><p>Set luma strength.
</p>
<p>Must be a double value in the range 0-1000, default is <code>1.0</code>.
</p>
</dd>
<dt> &lsquo;<samp>chroma_strength, cs</samp>&rsquo;</dt>
<dd><p>Set chroma strength.
</p>
<p>Must be a double value in the range 0-1000, default is <code>1.0</code>.
</p></dd>
</dl>
<a name="pad"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pad">28.62 pad</a></h2>
<p>Add paddings to the input image, and place the original input at the
given coordinates <var>x</var>, <var>y</var>.
</p>
<p>This filter accepts the following parameters:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>height, h</samp>&rsquo;</dt>
<dd><p>Specify an expression for the size of the output image with the
paddings added. If the value for <var>width</var> or <var>height</var> is 0, the
corresponding input size is used for the output.
</p>
<p>The <var>width</var> expression can reference the value set by the
<var>height</var> expression, and vice versa.
</p>
<p>The default value of <var>width</var> and <var>height</var> is 0.
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>Specify an expression for the offsets where to place the input image
in the padded area with respect to the top/left border of the output
image.
</p>
<p>The <var>x</var> expression can reference the value set by the <var>y</var>
expression, and vice versa.
</p>
<p>The default value of <var>x</var> and <var>y</var> is 0.
</p>
</dd>
<dt> &lsquo;<samp>color</samp>&rsquo;</dt>
<dd><p>Specify the color of the padded area. For the syntax of this option,
check the &quot;Color&quot; section in the ffmpeg-utils manual.
</p>
<p>The default value of <var>color</var> is &quot;black&quot;.
</p></dd>
</dl>
<p>The value for the <var>width</var>, <var>height</var>, <var>x</var>, and <var>y</var>
options are expressions containing the following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>in_w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>in_h</samp>&rsquo;</dt>
<dd><p>the input video width and height
</p>
</dd>
<dt> &lsquo;<samp>iw</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ih</samp>&rsquo;</dt>
<dd><p>same as <var>in_w</var> and <var>in_h</var>
</p>
</dd>
<dt> &lsquo;<samp>out_w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>out_h</samp>&rsquo;</dt>
<dd><p>the output width and height, that is the size of the padded area as
specified by the <var>width</var> and <var>height</var> expressions
</p>
</dd>
<dt> &lsquo;<samp>ow</samp>&rsquo;</dt>
<dt> &lsquo;<samp>oh</samp>&rsquo;</dt>
<dd><p>same as <var>out_w</var> and <var>out_h</var>
</p>
</dd>
<dt> &lsquo;<samp>x</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y</samp>&rsquo;</dt>
<dd><p>x and y offsets as specified by the <var>x</var> and <var>y</var>
expressions, or NAN if not yet specified
</p>
</dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>same as <var>iw</var> / <var>ih</var>
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>input sample aspect ratio
</p>
</dd>
<dt> &lsquo;<samp>dar</samp>&rsquo;</dt>
<dd><p>input display aspect ratio, it is the same as (<var>iw</var> / <var>ih</var>) * <var>sar</var>
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p></dd>
</dl>
<a name="Examples-36"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-36">28.62.1 Examples</a></h3>
<ul>
<li>
Add paddings with color &quot;violet&quot; to the input video. Output video
size is 640x480, the top-left corner of the input video is placed at
column 0, row 40:
<table><tr><td>&nbsp;</td><td><pre class="example">pad=640:480:0:40:violet
</pre></td></tr></table>
<p>The example above is equivalent to the following command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pad=width=640:height=480:x=0:y=40:color=violet
</pre></td></tr></table>
</li><li>
Pad the input to get an output with dimensions increased by 3/2,
and put the input video at the center of the padded area:
<table><tr><td>&nbsp;</td><td><pre class="example">pad=&quot;3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2&quot;
</pre></td></tr></table>
</li><li>
Pad the input to get a squared output with size equal to the maximum
value between the input width and height, and put the input video at
the center of the padded area:
<table><tr><td>&nbsp;</td><td><pre class="example">pad=&quot;max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2&quot;
</pre></td></tr></table>
</li><li>
Pad the input to get a final w/h ratio of 16:9:
<table><tr><td>&nbsp;</td><td><pre class="example">pad=&quot;ih*16/9:ih:(ow-iw)/2:(oh-ih)/2&quot;
</pre></td></tr></table>
</li><li>
In case of anamorphic video, in order to set the output display aspect
correctly, it is necessary to use <var>sar</var> in the expression,
according to the relation:
<table><tr><td>&nbsp;</td><td><pre class="example">(ih * X / ih) * sar = output_dar
X = output_dar / sar
</pre></td></tr></table>
<p>Thus the previous example needs to be modified to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">pad=&quot;ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2&quot;
</pre></td></tr></table>
</li><li>
Double output size and put the input video in the bottom-right
corner of the output padded area:
<table><tr><td>&nbsp;</td><td><pre class="example">pad=&quot;2*iw:2*ih:ow-iw:oh-ih&quot;
</pre></td></tr></table>
</li></ul>
<a name="perspective"></a>
<h2 class="section"><a href="ffplay-all.html#toc-perspective">28.63 perspective</a></h2>
<p>Correct perspective of video not recorded perpendicular to the screen.
</p>
<p>A description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>x0</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y0</samp>&rsquo;</dt>
<dt> &lsquo;<samp>x1</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y1</samp>&rsquo;</dt>
<dt> &lsquo;<samp>x2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>x3</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y3</samp>&rsquo;</dt>
<dd><p>Set coordinates expression for top left, top right, bottom left and bottom right corners.
Default values are <code>0:0:W:0:0:H:W:H</code> with which perspective will remain unchanged.
</p>
<p>The expressions can use the following variables:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>W</samp>&rsquo;</dt>
<dt> &lsquo;<samp>H</samp>&rsquo;</dt>
<dd><p>the width and height of video frame.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>interpolation</samp>&rsquo;</dt>
<dd><p>Set interpolation for perspective correction.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>linear</samp>&rsquo;</dt>
<dt> &lsquo;<samp>cubic</samp>&rsquo;</dt>
</dl>
<p>Default value is &lsquo;<samp>linear</samp>&rsquo;.
</p></dd>
</dl>
<a name="phase"></a>
<h2 class="section"><a href="ffplay-all.html#toc-phase">28.64 phase</a></h2>
<p>Delay interlaced video by one field time so that the field order changes.
</p>
<p>The intended use is to fix PAL movies that have been captured with the
opposite field order to the film-to-video transfer.
</p>
<p>A description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set phase mode.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>Capture field order top-first, transfer bottom-first.
Filter will delay the bottom field.
</p>
</dd>
<dt> &lsquo;<samp>b</samp>&rsquo;</dt>
<dd><p>Capture field order bottom-first, transfer top-first.
Filter will delay the top field.
</p>
</dd>
<dt> &lsquo;<samp>p</samp>&rsquo;</dt>
<dd><p>Capture and transfer with the same field order. This mode only exists
for the documentation of the other options to refer to, but if you
actually select it, the filter will faithfully do nothing.
</p>
</dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>Capture field order determined automatically by field flags, transfer
opposite.
Filter selects among &lsquo;<samp>t</samp>&rsquo; and &lsquo;<samp>b</samp>&rsquo; modes on a frame by frame
basis using field flags. If no field information is available,
then this works just like &lsquo;<samp>u</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>u</samp>&rsquo;</dt>
<dd><p>Capture unknown or varying, transfer opposite.
Filter selects among &lsquo;<samp>t</samp>&rsquo; and &lsquo;<samp>b</samp>&rsquo; on a frame by frame basis by
analyzing the images and selecting the alternative that produces best
match between the fields.
</p>
</dd>
<dt> &lsquo;<samp>T</samp>&rsquo;</dt>
<dd><p>Capture top-first, transfer unknown or varying.
Filter selects among &lsquo;<samp>t</samp>&rsquo; and &lsquo;<samp>p</samp>&rsquo; using image analysis.
</p>
</dd>
<dt> &lsquo;<samp>B</samp>&rsquo;</dt>
<dd><p>Capture bottom-first, transfer unknown or varying.
Filter selects among &lsquo;<samp>b</samp>&rsquo; and &lsquo;<samp>p</samp>&rsquo; using image analysis.
</p>
</dd>
<dt> &lsquo;<samp>A</samp>&rsquo;</dt>
<dd><p>Capture determined by field flags, transfer unknown or varying.
Filter selects among &lsquo;<samp>t</samp>&rsquo;, &lsquo;<samp>b</samp>&rsquo; and &lsquo;<samp>p</samp>&rsquo; using field flags and
image analysis. If no field information is available, then this works just
like &lsquo;<samp>U</samp>&rsquo;. This is the default mode.
</p>
</dd>
<dt> &lsquo;<samp>U</samp>&rsquo;</dt>
<dd><p>Both capture and transfer unknown or varying.
Filter selects among &lsquo;<samp>t</samp>&rsquo;, &lsquo;<samp>b</samp>&rsquo; and &lsquo;<samp>p</samp>&rsquo; using image analysis only.
</p></dd>
</dl>
</dd>
</dl>
<a name="pixdesctest"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pixdesctest">28.65 pixdesctest</a></h2>
<p>Pixel format descriptor test filter, mainly useful for internal
testing. The output video should be equal to the input video.
</p>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">format=monow, pixdesctest
</pre></td></tr></table>
<p>can be used to test the monowhite pixel format descriptor definition.
</p>
<a name="pp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pp">28.66 pp</a></h2>
<p>Enable the specified chain of postprocessing subfilters using libpostproc. This
library should be automatically selected with a GPL build (<code>--enable-gpl</code>).
Subfilters must be separated by &rsquo;/&rsquo; and can be disabled by prepending a &rsquo;-&rsquo;.
Each subfilter and some options have a short and a long name that can be used
interchangeably, i.e. dr/dering are the same.
</p>
<p>The filters accept the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>subfilters</samp>&rsquo;</dt>
<dd><p>Set postprocessing subfilters string.
</p></dd>
</dl>
<p>All subfilters share common options to determine their scope:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>a/autoq</samp>&rsquo;</dt>
<dd><p>Honor the quality commands for this subfilter.
</p>
</dd>
<dt> &lsquo;<samp>c/chrom</samp>&rsquo;</dt>
<dd><p>Do chrominance filtering, too (default).
</p>
</dd>
<dt> &lsquo;<samp>y/nochrom</samp>&rsquo;</dt>
<dd><p>Do luminance filtering only (no chrominance).
</p>
</dd>
<dt> &lsquo;<samp>n/noluma</samp>&rsquo;</dt>
<dd><p>Do chrominance filtering only (no luminance).
</p></dd>
</dl>
<p>These options can be appended after the subfilter name, separated by a &rsquo;|&rsquo;.
</p>
<p>Available subfilters are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>hb/hdeblock[|difference[|flatness]]</samp>&rsquo;</dt>
<dd><p>Horizontal deblocking filter
</p><dl compact="compact">
<dt> &lsquo;<samp>difference</samp>&rsquo;</dt>
<dd><p>Difference factor where higher values mean more deblocking (default: <code>32</code>).
</p></dd>
<dt> &lsquo;<samp>flatness</samp>&rsquo;</dt>
<dd><p>Flatness threshold where lower values mean more deblocking (default: <code>39</code>).
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>vb/vdeblock[|difference[|flatness]]</samp>&rsquo;</dt>
<dd><p>Vertical deblocking filter
</p><dl compact="compact">
<dt> &lsquo;<samp>difference</samp>&rsquo;</dt>
<dd><p>Difference factor where higher values mean more deblocking (default: <code>32</code>).
</p></dd>
<dt> &lsquo;<samp>flatness</samp>&rsquo;</dt>
<dd><p>Flatness threshold where lower values mean more deblocking (default: <code>39</code>).
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>ha/hadeblock[|difference[|flatness]]</samp>&rsquo;</dt>
<dd><p>Accurate horizontal deblocking filter
</p><dl compact="compact">
<dt> &lsquo;<samp>difference</samp>&rsquo;</dt>
<dd><p>Difference factor where higher values mean more deblocking (default: <code>32</code>).
</p></dd>
<dt> &lsquo;<samp>flatness</samp>&rsquo;</dt>
<dd><p>Flatness threshold where lower values mean more deblocking (default: <code>39</code>).
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>va/vadeblock[|difference[|flatness]]</samp>&rsquo;</dt>
<dd><p>Accurate vertical deblocking filter
</p><dl compact="compact">
<dt> &lsquo;<samp>difference</samp>&rsquo;</dt>
<dd><p>Difference factor where higher values mean more deblocking (default: <code>32</code>).
</p></dd>
<dt> &lsquo;<samp>flatness</samp>&rsquo;</dt>
<dd><p>Flatness threshold where lower values mean more deblocking (default: <code>39</code>).
</p></dd>
</dl>
</dd>
</dl>
<p>The horizontal and vertical deblocking filters share the difference and
flatness values so you cannot set different horizontal and vertical
thresholds.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>h1/x1hdeblock</samp>&rsquo;</dt>
<dd><p>Experimental horizontal deblocking filter
</p>
</dd>
<dt> &lsquo;<samp>v1/x1vdeblock</samp>&rsquo;</dt>
<dd><p>Experimental vertical deblocking filter
</p>
</dd>
<dt> &lsquo;<samp>dr/dering</samp>&rsquo;</dt>
<dd><p>Deringing filter
</p>
</dd>
<dt> &lsquo;<samp>tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>threshold1</samp>&rsquo;</dt>
<dd><p>larger -&gt; stronger filtering
</p></dd>
<dt> &lsquo;<samp>threshold2</samp>&rsquo;</dt>
<dd><p>larger -&gt; stronger filtering
</p></dd>
<dt> &lsquo;<samp>threshold3</samp>&rsquo;</dt>
<dd><p>larger -&gt; stronger filtering
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>al/autolevels[:f/fullyrange], automatic brightness / contrast correction</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>f/fullyrange</samp>&rsquo;</dt>
<dd><p>Stretch luminance to <code>0-255</code>.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>lb/linblenddeint</samp>&rsquo;</dt>
<dd><p>Linear blend deinterlacing filter that deinterlaces the given block by
filtering all lines with a <code>(1 2 1)</code> filter.
</p>
</dd>
<dt> &lsquo;<samp>li/linipoldeint</samp>&rsquo;</dt>
<dd><p>Linear interpolating deinterlacing filter that deinterlaces the given block by
linearly interpolating every second line.
</p>
</dd>
<dt> &lsquo;<samp>ci/cubicipoldeint</samp>&rsquo;</dt>
<dd><p>Cubic interpolating deinterlacing filter deinterlaces the given block by
cubically interpolating every second line.
</p>
</dd>
<dt> &lsquo;<samp>md/mediandeint</samp>&rsquo;</dt>
<dd><p>Median deinterlacing filter that deinterlaces the given block by applying a
median filter to every second line.
</p>
</dd>
<dt> &lsquo;<samp>fd/ffmpegdeint</samp>&rsquo;</dt>
<dd><p>FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
second line with a <code>(-1 4 2 4 -1)</code> filter.
</p>
</dd>
<dt> &lsquo;<samp>l5/lowpass5</samp>&rsquo;</dt>
<dd><p>Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
block by filtering all lines with a <code>(-1 2 6 2 -1)</code> filter.
</p>
</dd>
<dt> &lsquo;<samp>fq/forceQuant[|quantizer]</samp>&rsquo;</dt>
<dd><p>Overrides the quantizer table from the input with the constant quantizer you
specify.
</p><dl compact="compact">
<dt> &lsquo;<samp>quantizer</samp>&rsquo;</dt>
<dd><p>Quantizer to use
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>de/default</samp>&rsquo;</dt>
<dd><p>Default pp filter combination (<code>hb|a,vb|a,dr|a</code>)
</p>
</dd>
<dt> &lsquo;<samp>fa/fast</samp>&rsquo;</dt>
<dd><p>Fast pp filter combination (<code>h1|a,v1|a,dr|a</code>)
</p>
</dd>
<dt> &lsquo;<samp>ac</samp>&rsquo;</dt>
<dd><p>High quality pp filter combination (<code>ha|a|128|7,va|a,dr|a</code>)
</p></dd>
</dl>
<a name="Examples-35"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-35">28.66.1 Examples</a></h3>
<ul>
<li>
Apply horizontal and vertical deblocking, deringing and automatic
brightness/contrast:
<table><tr><td>&nbsp;</td><td><pre class="example">pp=hb/vb/dr/al
</pre></td></tr></table>
</li><li>
Apply default filters without brightness/contrast correction:
<table><tr><td>&nbsp;</td><td><pre class="example">pp=de/-al
</pre></td></tr></table>
</li><li>
Apply default filters and temporal denoiser:
<table><tr><td>&nbsp;</td><td><pre class="example">pp=default/tmpnoise|1|2|3
</pre></td></tr></table>
</li><li>
Apply deblocking on luminance only, and switch vertical deblocking on or off
automatically depending on available CPU time:
<table><tr><td>&nbsp;</td><td><pre class="example">pp=hb|y/vb|a
</pre></td></tr></table>
</li></ul>
<a name="psnr"></a>
<h2 class="section"><a href="ffplay-all.html#toc-psnr">28.67 psnr</a></h2>
<p>Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
Ratio) between two input videos.
</p>
<p>This filter takes in input two input videos, the first input is
considered the &quot;main&quot; source and is passed unchanged to the
output. The second input is used as a &quot;reference&quot; video for computing
the PSNR.
</p>
<p>Both video inputs must have the same resolution and pixel format for
this filter to work correctly. Also it assumes that both inputs
have the same number of frames, which are compared one by one.
</p>
<p>The obtained average PSNR is printed through the logging system.
</p>
<p>The filter stores the accumulated MSE (mean squared error) of each
frame, and at the end of the processing it is averaged across all frames
equally, and the following formula is applied to obtain the PSNR:
</p>
<table><tr><td>&nbsp;</td><td><pre class="example">PSNR = 10*log10(MAX^2/MSE)
</pre></td></tr></table>
<p>Where MAX is the average of the maximum values of each component of the
image.
</p>
<p>The description of the accepted parameters follows.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>stats_file, f</samp>&rsquo;</dt>
<dd><p>If specified the filter will use the named file to save the PSNR of
each individual frame.
</p></dd>
</dl>
<p>The file printed if <var>stats_file</var> is selected, contains a sequence of
key/value pairs of the form <var>key</var>:<var>value</var> for each compared
couple of frames.
</p>
<p>A description of each shown parameter follows:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>sequential number of the input frame, starting from 1
</p>
</dd>
<dt> &lsquo;<samp>mse_avg</samp>&rsquo;</dt>
<dd><p>Mean Square Error pixel-by-pixel average difference of the compared
frames, averaged over all the image components.
</p>
</dd>
<dt> &lsquo;<samp>mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a</samp>&rsquo;</dt>
<dd><p>Mean Square Error pixel-by-pixel average difference of the compared
frames for the component specified by the suffix.
</p>
</dd>
<dt> &lsquo;<samp>psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a</samp>&rsquo;</dt>
<dd><p>Peak Signal to Noise ratio of the compared frames for the component
specified by the suffix.
</p></dd>
</dl>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
[main][ref] psnr=&quot;stats_file=stats.log&quot; [out]
</pre></td></tr></table>
<p>On this example the input file being processed is compared with the
reference file &lsquo;<tt>ref_movie.mpg</tt>&rsquo;. The PSNR of each individual frame
is stored in &lsquo;<tt>stats.log</tt>&rsquo;.
</p>
<p><a name="pullup"></a>
</p><a name="pullup-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-pullup-1">28.68 pullup</a></h2>
<p>Pulldown reversal (inverse telecine) filter, capable of handling mixed
hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
content.
</p>
<p>The pullup filter is designed to take advantage of future context in making
its decisions. This filter is stateless in the sense that it does not lock
onto a pattern to follow, but it instead looks forward to the following
fields in order to identify matches and rebuild progressive frames.
</p>
<p>To produce content with an even framerate, insert the fps filter after
pullup, use <code>fps=24000/1001</code> if the input frame rate is 29.97fps,
<code>fps=24</code> for 30fps and the (rare) telecined 25fps input.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>jl</samp>&rsquo;</dt>
<dt> &lsquo;<samp>jr</samp>&rsquo;</dt>
<dt> &lsquo;<samp>jt</samp>&rsquo;</dt>
<dt> &lsquo;<samp>jb</samp>&rsquo;</dt>
<dd><p>These options set the amount of &quot;junk&quot; to ignore at the left, right, top, and
bottom of the image, respectively. Left and right are in units of 8 pixels,
while top and bottom are in units of 2 lines.
The default is 8 pixels on each side.
</p>
</dd>
<dt> &lsquo;<samp>sb</samp>&rsquo;</dt>
<dd><p>Set the strict breaks. Setting this option to 1 will reduce the chances of
filter generating an occasional mismatched frame, but it may also cause an
excessive number of frames to be dropped during high motion sequences.
Conversely, setting it to -1 will make filter match fields more easily.
This may help processing of video where there is slight blurring between
the fields, but may also cause there to be interlaced frames in the output.
Default value is <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>mp</samp>&rsquo;</dt>
<dd><p>Set the metric plane to use. It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>l</samp>&rsquo;</dt>
<dd><p>Use luma plane.
</p>
</dd>
<dt> &lsquo;<samp>u</samp>&rsquo;</dt>
<dd><p>Use chroma blue plane.
</p>
</dd>
<dt> &lsquo;<samp>v</samp>&rsquo;</dt>
<dd><p>Use chroma red plane.
</p></dd>
</dl>
<p>This option may be set to use chroma plane instead of the default luma plane
for doing filter&rsquo;s computations. This may improve accuracy on very clean
source material, but more likely will decrease accuracy, especially if there
is chroma noise (rainbow effect) or any grayscale video.
The main purpose of setting &lsquo;<samp>mp</samp>&rsquo; to a chroma plane is to reduce CPU
load and make pullup usable in realtime on slow machines.
</p></dd>
</dl>
<p>For best results (without duplicated frames in the output file) it is
necessary to change the output frame rate. For example, to inverse
telecine NTSC input:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i input -vf pullup -r 24000/1001 ...
</pre></td></tr></table>
<a name="removelogo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-removelogo">28.69 removelogo</a></h2>
<p>Suppress a TV station logo, using an image file to determine which
pixels comprise the logo. It works by filling in the pixels that
comprise the logo with neighboring pixels.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filename, f</samp>&rsquo;</dt>
<dd><p>Set the filter bitmap file, which can be any image format supported by
libavformat. The width and height of the image file must match those of the
video stream being processed.
</p></dd>
</dl>
<p>Pixels in the provided bitmap image with a value of zero are not
considered part of the logo, non-zero pixels are considered part of
the logo. If you use white (255) for the logo and black (0) for the
rest, you will be safe. For making the filter bitmap, it is
recommended to take a screen capture of a black frame with the logo
visible, and then using a threshold filter followed by the erode
filter once or twice.
</p>
<p>If needed, little splotches can be fixed manually. Remember that if
logo pixels are not covered, the filter quality will be much
reduced. Marking too many pixels as part of the logo does not hurt as
much, but it will increase the amount of blurring needed to cover over
the image and will destroy more information than necessary, and extra
pixels will slow things down on a large logo.
</p>
<a name="rotate"></a>
<h2 class="section"><a href="ffplay-all.html#toc-rotate">28.70 rotate</a></h2>
<p>Rotate video by an arbitrary angle expressed in radians.
</p>
<p>The filter accepts the following options:
</p>
<p>A description of the optional parameters follows.
</p><dl compact="compact">
<dt> &lsquo;<samp>angle, a</samp>&rsquo;</dt>
<dd><p>Set an expression for the angle by which to rotate the input video
clockwise, expressed as a number of radians. A negative value will
result in a counter-clockwise rotation. By default it is set to &quot;0&quot;.
</p>
<p>This expression is evaluated for each frame.
</p>
</dd>
<dt> &lsquo;<samp>out_w, ow</samp>&rsquo;</dt>
<dd><p>Set the output width expression, default value is &quot;iw&quot;.
This expression is evaluated just once during configuration.
</p>
</dd>
<dt> &lsquo;<samp>out_h, oh</samp>&rsquo;</dt>
<dd><p>Set the output height expression, default value is &quot;ih&quot;.
This expression is evaluated just once during configuration.
</p>
</dd>
<dt> &lsquo;<samp>bilinear</samp>&rsquo;</dt>
<dd><p>Enable bilinear interpolation if set to 1, a value of 0 disables
it. Default value is 1.
</p>
</dd>
<dt> &lsquo;<samp>fillcolor, c</samp>&rsquo;</dt>
<dd><p>Set the color used to fill the output area not covered by the rotated
image. For the generalsyntax of this option, check the &quot;Color&quot; section in the
ffmpeg-utils manual. If the special value &quot;none&quot; is selected then no
background is printed (useful for example if the background is never shown).
</p>
<p>Default value is &quot;black&quot;.
</p></dd>
</dl>
<p>The expressions for the angle and the output size can contain the
following constants and functions:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>sequential number of the input frame, starting from 0. It is always NAN
before the first frame is filtered.
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>time in seconds of the input frame, it is set to 0 when the filter is
configured. It is always NAN before the first frame is filtered.
</p>
</dd>
<dt> &lsquo;<samp>hsub</samp>&rsquo;</dt>
<dt> &lsquo;<samp>vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p>
</dd>
<dt> &lsquo;<samp>in_w, iw</samp>&rsquo;</dt>
<dt> &lsquo;<samp>in_h, ih</samp>&rsquo;</dt>
<dd><p>the input video width and height
</p>
</dd>
<dt> &lsquo;<samp>out_w, ow</samp>&rsquo;</dt>
<dt> &lsquo;<samp>out_h, oh</samp>&rsquo;</dt>
<dd><p>the output width and height, that is the size of the padded area as
specified by the <var>width</var> and <var>height</var> expressions
</p>
</dd>
<dt> &lsquo;<samp>rotw(a)</samp>&rsquo;</dt>
<dt> &lsquo;<samp>roth(a)</samp>&rsquo;</dt>
<dd><p>the minimal width/height required for completely containing the input
video rotated by <var>a</var> radians.
</p>
<p>These are only available when computing the &lsquo;<samp>out_w</samp>&rsquo; and
&lsquo;<samp>out_h</samp>&rsquo; expressions.
</p></dd>
</dl>
<a name="Examples-63"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-63">28.70.1 Examples</a></h3>
<ul>
<li>
Rotate the input by PI/6 radians clockwise:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate=PI/6
</pre></td></tr></table>
</li><li>
Rotate the input by PI/6 radians counter-clockwise:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate=-PI/6
</pre></td></tr></table>
</li><li>
Rotate the input by 45 degrees clockwise:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate=45*PI/180
</pre></td></tr></table>
</li><li>
Apply a constant rotation with period T, starting from an angle of PI/3:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate=PI/3+2*PI*t/T
</pre></td></tr></table>
</li><li>
Make the input video rotation oscillating with a period of T
seconds and an amplitude of A radians:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate=A*sin(2*PI/T*t)
</pre></td></tr></table>
</li><li>
Rotate the video, output size is chosen so that the whole rotating
input video is always completely contained in the output:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
</pre></td></tr></table>
</li><li>
Rotate the video, reduce the output size so that no background is ever
shown:
<table><tr><td>&nbsp;</td><td><pre class="example">rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
</pre></td></tr></table>
</li></ul>
<a name="Commands-5"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands-5">28.70.2 Commands</a></h3>
<p>The filter supports the following commands:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>a, angle</samp>&rsquo;</dt>
<dd><p>Set the angle expression.
The command accepts the same syntax of the corresponding option.
</p>
<p>If the specified expression is not valid, it is kept at its current
value.
</p></dd>
</dl>
<a name="sab"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sab">28.71 sab</a></h2>
<p>Apply Shape Adaptive Blur.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_radius, lr</samp>&rsquo;</dt>
<dd><p>Set luma blur filter strength, must be a value in range 0.1-4.0, default
value is 1.0. A greater value will result in a more blurred image, and
in slower processing.
</p>
</dd>
<dt> &lsquo;<samp>luma_pre_filter_radius, lpfr</samp>&rsquo;</dt>
<dd><p>Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>luma_strength, ls</samp>&rsquo;</dt>
<dd><p>Set luma maximum difference between pixels to still be considered, must
be a value in the 0.1-100.0 range, default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>chroma_radius, cr</samp>&rsquo;</dt>
<dd><p>Set chroma blur filter strength, must be a value in range 0.1-4.0. A
greater value will result in a more blurred image, and in slower
processing.
</p>
</dd>
<dt> &lsquo;<samp>chroma_pre_filter_radius, cpfr</samp>&rsquo;</dt>
<dd><p>Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
</p>
</dd>
<dt> &lsquo;<samp>chroma_strength, cs</samp>&rsquo;</dt>
<dd><p>Set chroma maximum difference between pixels to still be considered,
must be a value in the 0.1-100.0 range.
</p></dd>
</dl>
<p>Each chroma option value, if not explicitly specified, is set to the
corresponding luma option value.
</p>
<p><a name="scale"></a>
</p><a name="scale-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-scale-1">28.72 scale</a></h2>
<p>Scale (resize) the input video, using the libswscale library.
</p>
<p>The scale filter forces the output display aspect ratio to be the same
of the input, by changing the output sample aspect ratio.
</p>
<p>If the input image format is different from the format requested by
the next filter, the scale filter will convert the input to the
requested format.
</p>
<a name="Options-5"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-5">28.72.1 Options</a></h3>
<p>The filter accepts the following options, or any of the options
supported by the libswscale scaler.
</p>
<p>See <a href="ffmpeg-scaler.html#scaler_005foptions">(ffmpeg-scaler)scaler_options</a> for
the complete list of scaler options.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>width, w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>height, h</samp>&rsquo;</dt>
<dd><p>Set the output video dimension expression. Default value is the input
dimension.
</p>
<p>If the value is 0, the input width is used for the output.
</p>
<p>If one of the values is -1, the scale filter will use a value that
maintains the aspect ratio of the input image, calculated from the
other specified dimension. If both of them are -1, the input size is
used
</p>
<p>If one of the values is -n with n &gt; 1, the scale filter will also use a value
that maintains the aspect ratio of the input image, calculated from the other
specified dimension. After that it will, however, make sure that the calculated
dimension is divisible by n and adjust the value if necessary.
</p>
<p>See below for the list of accepted constants for use in the dimension
expression.
</p>
</dd>
<dt> &lsquo;<samp>interl</samp>&rsquo;</dt>
<dd><p>Set the interlacing mode. It accepts the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>1</samp>&rsquo;</dt>
<dd><p>Force interlaced aware scaling.
</p>
</dd>
<dt> &lsquo;<samp>0</samp>&rsquo;</dt>
<dd><p>Do not apply interlaced scaling.
</p>
</dd>
<dt> &lsquo;<samp>-1</samp>&rsquo;</dt>
<dd><p>Select interlaced aware scaling depending on whether the source frames
are flagged as interlaced or not.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>0</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>flags</samp>&rsquo;</dt>
<dd><p>Set libswscale scaling flags. See
<a href="ffmpeg-scaler.html#sws_005fflags">(ffmpeg-scaler)sws_flags</a> for the
complete list of values. If not explicitly specified the filter applies
the default flags.
</p>
</dd>
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Set the video size. For the syntax of this option, check the &quot;Video size&quot;
section in the ffmpeg-utils manual.
</p>
</dd>
<dt> &lsquo;<samp>in_color_matrix</samp>&rsquo;</dt>
<dt> &lsquo;<samp>out_color_matrix</samp>&rsquo;</dt>
<dd><p>Set in/output YCbCr color space type.
</p>
<p>This allows the autodetected value to be overridden as well as allows forcing
a specific value used for the output and encoder.
</p>
<p>If not specified, the color space type depends on the pixel format.
</p>
<p>Possible values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>Choose automatically.
</p>
</dd>
<dt> &lsquo;<samp>bt709</samp>&rsquo;</dt>
<dd><p>Format conforming to International Telecommunication Union (ITU)
Recommendation BT.709.
</p>
</dd>
<dt> &lsquo;<samp>fcc</samp>&rsquo;</dt>
<dd><p>Set color space conforming to the United States Federal Communications
Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
</p>
</dd>
<dt> &lsquo;<samp>bt601</samp>&rsquo;</dt>
<dd><p>Set color space conforming to:
</p>
<ul>
<li>
ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
</li><li>
ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
</li><li>
Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
</li></ul>
</dd>
<dt> &lsquo;<samp>smpte240m</samp>&rsquo;</dt>
<dd><p>Set color space conforming to SMPTE ST 240:1999.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>in_range</samp>&rsquo;</dt>
<dt> &lsquo;<samp>out_range</samp>&rsquo;</dt>
<dd><p>Set in/output YCbCr sample range.
</p>
<p>This allows the autodetected value to be overridden as well as allows forcing
a specific value used for the output and encoder. If not specified, the
range depends on the pixel format. Possible values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>Choose automatically.
</p>
</dd>
<dt> &lsquo;<samp>jpeg/full/pc</samp>&rsquo;</dt>
<dd><p>Set full range (0-255 in case of 8-bit luma).
</p>
</dd>
<dt> &lsquo;<samp>mpeg/tv</samp>&rsquo;</dt>
<dd><p>Set &quot;MPEG&quot; range (16-235 in case of 8-bit luma).
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>force_original_aspect_ratio</samp>&rsquo;</dt>
<dd><p>Enable decreasing or increasing output video width or height if necessary to
keep the original aspect ratio. Possible values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>disable</samp>&rsquo;</dt>
<dd><p>Scale the video as specified and disable this feature.
</p>
</dd>
<dt> &lsquo;<samp>decrease</samp>&rsquo;</dt>
<dd><p>The output video dimensions will automatically be decreased if needed.
</p>
</dd>
<dt> &lsquo;<samp>increase</samp>&rsquo;</dt>
<dd><p>The output video dimensions will automatically be increased if needed.
</p>
</dd>
</dl>
<p>One useful instance of this option is that when you know a specific device&rsquo;s
maximum allowed resolution, you can use this to limit the output video to
that, while retaining the aspect ratio. For example, device A allows
1280x720 playback, and your video is 1920x800. Using this option (set it to
decrease) and specifying 1280x720 to the command line makes the output
1280x533.
</p>
<p>Please note that this is a different thing than specifying -1 for &lsquo;<samp>w</samp>&rsquo;
or &lsquo;<samp>h</samp>&rsquo;, you still need to specify the output resolution for this option
to work.
</p>
</dd>
</dl>
<p>The values of the &lsquo;<samp>w</samp>&rsquo; and &lsquo;<samp>h</samp>&rsquo; options are expressions
containing the following constants:
</p>
<dl compact="compact">
<dt> <var>in_w</var></dt>
<dt> <var>in_h</var></dt>
<dd><p>the input width and height
</p>
</dd>
<dt> <var>iw</var></dt>
<dt> <var>ih</var></dt>
<dd><p>same as <var>in_w</var> and <var>in_h</var>
</p>
</dd>
<dt> <var>out_w</var></dt>
<dt> <var>out_h</var></dt>
<dd><p>the output (scaled) width and height
</p>
</dd>
<dt> <var>ow</var></dt>
<dt> <var>oh</var></dt>
<dd><p>same as <var>out_w</var> and <var>out_h</var>
</p>
</dd>
<dt> <var>a</var></dt>
<dd><p>same as <var>iw</var> / <var>ih</var>
</p>
</dd>
<dt> <var>sar</var></dt>
<dd><p>input sample aspect ratio
</p>
</dd>
<dt> <var>dar</var></dt>
<dd><p>input display aspect ratio. Calculated from <code>(iw / ih) * sar</code>.
</p>
</dd>
<dt> <var>hsub</var></dt>
<dt> <var>vsub</var></dt>
<dd><p>horizontal and vertical input chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p>
</dd>
<dt> <var>ohsub</var></dt>
<dt> <var>ovsub</var></dt>
<dd><p>horizontal and vertical output chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p></dd>
</dl>
<a name="Examples-41"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-41">28.72.2 Examples</a></h3>
<ul>
<li>
Scale the input video to a size of 200x100:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=w=200:h=100
</pre></td></tr></table>
<p>This is equivalent to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">scale=200:100
</pre></td></tr></table>
<p>or:
</p><table><tr><td>&nbsp;</td><td><pre class="example">scale=200x100
</pre></td></tr></table>
</li><li>
Specify a size abbreviation for the output size:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=qcif
</pre></td></tr></table>
<p>which can also be written as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">scale=size=qcif
</pre></td></tr></table>
</li><li>
Scale the input to 2x:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=w=2*iw:h=2*ih
</pre></td></tr></table>
</li><li>
The above is the same as:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=2*in_w:2*in_h
</pre></td></tr></table>
</li><li>
Scale the input to 2x with forced interlaced scaling:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=2*iw:2*ih:interl=1
</pre></td></tr></table>
</li><li>
Scale the input to half size:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=w=iw/2:h=ih/2
</pre></td></tr></table>
</li><li>
Increase the width, and set the height to the same size:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=3/2*iw:ow
</pre></td></tr></table>
</li><li>
Seek for Greek harmony:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=iw:1/PHI*iw
scale=ih*PHI:ih
</pre></td></tr></table>
</li><li>
Increase the height, and set the width to 3/2 of the height:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=w=3/2*oh:h=3/5*ih
</pre></td></tr></table>
</li><li>
Increase the size, but make the size a multiple of the chroma
subsample values:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=&quot;trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub&quot;
</pre></td></tr></table>
</li><li>
Increase the width to a maximum of 500 pixels, keep the same input
aspect ratio:
<table><tr><td>&nbsp;</td><td><pre class="example">scale=w='min(500\, iw*3/2):h=-1'
</pre></td></tr></table>
</li></ul>
<a name="separatefields"></a>
<h2 class="section"><a href="ffplay-all.html#toc-separatefields">28.73 separatefields</a></h2>
<p>The <code>separatefields</code> takes a frame-based video input and splits
each frame into its components fields, producing a new half height clip
with twice the frame rate and twice the frame count.
</p>
<p>This filter use field-dominance information in frame to decide which
of each pair of fields to place first in the output.
If it gets it wrong use <a href="#setfield">setfield</a> filter before <code>separatefields</code> filter.
</p>
<a name="setdar_002c-setsar"></a>
<h2 class="section"><a href="ffplay-all.html#toc-setdar_002c-setsar">28.74 setdar, setsar</a></h2>
<p>The <code>setdar</code> filter sets the Display Aspect Ratio for the filter
output video.
</p>
<p>This is done by changing the specified Sample (aka Pixel) Aspect
Ratio, according to the following equation:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>DAR</var> = <var>HORIZONTAL_RESOLUTION</var> / <var>VERTICAL_RESOLUTION</var> * <var>SAR</var>
</pre></td></tr></table>
<p>Keep in mind that the <code>setdar</code> filter does not modify the pixel
dimensions of the video frame. Also the display aspect ratio set by
this filter may be changed by later filters in the filterchain,
e.g. in case of scaling or if another &quot;setdar&quot; or a &quot;setsar&quot; filter is
applied.
</p>
<p>The <code>setsar</code> filter sets the Sample (aka Pixel) Aspect Ratio for
the filter output video.
</p>
<p>Note that as a consequence of the application of this filter, the
output display aspect ratio will change according to the equation
above.
</p>
<p>Keep in mind that the sample aspect ratio set by the <code>setsar</code>
filter may be changed by later filters in the filterchain, e.g. if
another &quot;setsar&quot; or a &quot;setdar&quot; filter is applied.
</p>
<p>The filters accept the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>r, ratio, dar (<code>setdar</code> only), sar (<code>setsar</code> only)</samp>&rsquo;</dt>
<dd><p>Set the aspect ratio used by the filter.
</p>
<p>The parameter can be a floating point number string, an expression, or
a string of the form <var>num</var>:<var>den</var>, where <var>num</var> and
<var>den</var> are the numerator and denominator of the aspect ratio. If
the parameter is not specified, it is assumed the value &quot;0&quot;.
In case the form &quot;<var>num</var>:<var>den</var>&quot; is used, the <code>:</code> character
should be escaped.
</p>
</dd>
<dt> &lsquo;<samp>max</samp>&rsquo;</dt>
<dd><p>Set the maximum integer value to use for expressing numerator and
denominator when reducing the expressed aspect ratio to a rational.
Default value is <code>100</code>.
</p>
</dd>
</dl>
<p>The parameter <var>sar</var> is an expression containing
the following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>E, PI, PHI</samp>&rsquo;</dt>
<dd><p>the corresponding mathematical approximated values for e
(euler number), pi (greek PI), phi (golden ratio)
</p>
</dd>
<dt> &lsquo;<samp>w, h</samp>&rsquo;</dt>
<dd><p>the input width and height
</p>
</dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>same as <var>w</var> / <var>h</var>
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>input sample aspect ratio
</p>
</dd>
<dt> &lsquo;<samp>dar</samp>&rsquo;</dt>
<dd><p>input display aspect ratio, it is the same as (<var>w</var> / <var>h</var>) * <var>sar</var>
</p>
</dd>
<dt> &lsquo;<samp>hsub, vsub</samp>&rsquo;</dt>
<dd><p>horizontal and vertical chroma subsample values. For example for the
pixel format &quot;yuv422p&quot; <var>hsub</var> is 2 and <var>vsub</var> is 1.
</p></dd>
</dl>
<a name="Examples-43"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-43">28.74.1 Examples</a></h3>
<ul>
<li>
To change the display aspect ratio to 16:9, specify one of the following:
<table><tr><td>&nbsp;</td><td><pre class="example">setdar=dar=1.77777
setdar=dar=16/9
setdar=dar=1.77777
</pre></td></tr></table>
</li><li>
To change the sample aspect ratio to 10:11, specify:
<table><tr><td>&nbsp;</td><td><pre class="example">setsar=sar=10/11
</pre></td></tr></table>
</li><li>
To set a display aspect ratio of 16:9, and specify a maximum integer value of
1000 in the aspect ratio reduction, use the command:
<table><tr><td>&nbsp;</td><td><pre class="example">setdar=ratio=16/9:max=1000
</pre></td></tr></table>
</li></ul>
<p><a name="setfield"></a>
</p><a name="setfield-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-setfield-1">28.75 setfield</a></h2>
<p>Force field for the output video frame.
</p>
<p>The <code>setfield</code> filter marks the interlace type field for the
output frames. It does not change the input frame, but only sets the
corresponding property, which affects how the frame is treated by
following filters (e.g. <code>fieldorder</code> or <code>yadif</code>).
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>auto</samp>&rsquo;</dt>
<dd><p>Keep the same field property.
</p>
</dd>
<dt> &lsquo;<samp>bff</samp>&rsquo;</dt>
<dd><p>Mark the frame as bottom-field-first.
</p>
</dd>
<dt> &lsquo;<samp>tff</samp>&rsquo;</dt>
<dd><p>Mark the frame as top-field-first.
</p>
</dd>
<dt> &lsquo;<samp>prog</samp>&rsquo;</dt>
<dd><p>Mark the frame as progressive.
</p></dd>
</dl>
</dd>
</dl>
<a name="showinfo"></a>
<h2 class="section"><a href="ffplay-all.html#toc-showinfo">28.76 showinfo</a></h2>
<p>Show a line containing various information for each input video frame.
The input video is not modified.
</p>
<p>The shown line contains a sequence of key/value pairs of the form
<var>key</var>:<var>value</var>.
</p>
<p>A description of each shown parameter follows:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>sequential number of the input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dd><p>Presentation TimeStamp of the input frame, expressed as a number of
time base units. The time base unit depends on the filter input pad.
</p>
</dd>
<dt> &lsquo;<samp>pts_time</samp>&rsquo;</dt>
<dd><p>Presentation TimeStamp of the input frame, expressed as a number of
seconds
</p>
</dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>position of the frame in the input stream, -1 if this information in
unavailable and/or meaningless (for example in case of synthetic video)
</p>
</dd>
<dt> &lsquo;<samp>fmt</samp>&rsquo;</dt>
<dd><p>pixel format name
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>sample aspect ratio of the input frame, expressed in the form
<var>num</var>/<var>den</var>
</p>
</dd>
<dt> &lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>size of the input frame. For the syntax of this option, check the &quot;Video size&quot;
section in the ffmpeg-utils manual.
</p>
</dd>
<dt> &lsquo;<samp>i</samp>&rsquo;</dt>
<dd><p>interlaced mode (&quot;P&quot; for &quot;progressive&quot;, &quot;T&quot; for top field first, &quot;B&quot;
for bottom field first)
</p>
</dd>
<dt> &lsquo;<samp>iskey</samp>&rsquo;</dt>
<dd><p>1 if the frame is a key frame, 0 otherwise
</p>
</dd>
<dt> &lsquo;<samp>type</samp>&rsquo;</dt>
<dd><p>picture type of the input frame (&quot;I&quot; for an I-frame, &quot;P&quot; for a
P-frame, &quot;B&quot; for a B-frame, &quot;?&quot; for unknown type).
Check also the documentation of the <code>AVPictureType</code> enum and of
the <code>av_get_picture_type_char</code> function defined in
&lsquo;<tt>libavutil/avutil.h</tt>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>checksum</samp>&rsquo;</dt>
<dd><p>Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
</p>
</dd>
<dt> &lsquo;<samp>plane_checksum</samp>&rsquo;</dt>
<dd><p>Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
expressed in the form &quot;[<var>c0</var> <var>c1</var> <var>c2</var> <var>c3</var>]&quot;
</p></dd>
</dl>
<a name="shuffleplanes"></a>
<h2 class="section"><a href="ffplay-all.html#toc-shuffleplanes">28.77 shuffleplanes</a></h2>
<p>Reorder and/or duplicate video planes.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>map0</samp>&rsquo;</dt>
<dd><p>The index of the input plane to be used as the first output plane.
</p>
</dd>
<dt> &lsquo;<samp>map1</samp>&rsquo;</dt>
<dd><p>The index of the input plane to be used as the second output plane.
</p>
</dd>
<dt> &lsquo;<samp>map2</samp>&rsquo;</dt>
<dd><p>The index of the input plane to be used as the third output plane.
</p>
</dd>
<dt> &lsquo;<samp>map3</samp>&rsquo;</dt>
<dd><p>The index of the input plane to be used as the fourth output plane.
</p>
</dd>
</dl>
<p>The first plane has the index 0. The default is to keep the input unchanged.
</p>
<p>E.g.
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
</pre></td></tr></table>
<p>swaps the second and third planes of the input.
</p>
<p><a name="smartblur"></a>
</p><a name="smartblur-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-smartblur-1">28.78 smartblur</a></h2>
<p>Blur the input video without impacting the outlines.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_radius, lr</samp>&rsquo;</dt>
<dd><p>Set the luma radius. The option value must be a float number in
the range [0.1,5.0] that specifies the variance of the gaussian filter
used to blur the image (slower if larger). Default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>luma_strength, ls</samp>&rsquo;</dt>
<dd><p>Set the luma strength. The option value must be a float number
in the range [-1.0,1.0] that configures the blurring. A value included
in [0.0,1.0] will blur the image whereas a value included in
[-1.0,0.0] will sharpen the image. Default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>luma_threshold, lt</samp>&rsquo;</dt>
<dd><p>Set the luma threshold used as a coefficient to determine
whether a pixel should be blurred or not. The option value must be an
integer in the range [-30,30]. A value of 0 will filter all the image,
a value included in [0,30] will filter flat areas and a value included
in [-30,0] will filter edges. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>chroma_radius, cr</samp>&rsquo;</dt>
<dd><p>Set the chroma radius. The option value must be a float number in
the range [0.1,5.0] that specifies the variance of the gaussian filter
used to blur the image (slower if larger). Default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>chroma_strength, cs</samp>&rsquo;</dt>
<dd><p>Set the chroma strength. The option value must be a float number
in the range [-1.0,1.0] that configures the blurring. A value included
in [0.0,1.0] will blur the image whereas a value included in
[-1.0,0.0] will sharpen the image. Default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>chroma_threshold, ct</samp>&rsquo;</dt>
<dd><p>Set the chroma threshold used as a coefficient to determine
whether a pixel should be blurred or not. The option value must be an
integer in the range [-30,30]. A value of 0 will filter all the image,
a value included in [0,30] will filter flat areas and a value included
in [-30,0] will filter edges. Default value is 0.
</p></dd>
</dl>
<p>If a chroma option is not explicitly set, the corresponding luma value
is set.
</p>
<a name="stereo3d"></a>
<h2 class="section"><a href="ffplay-all.html#toc-stereo3d">28.79 stereo3d</a></h2>
<p>Convert between different stereoscopic image formats.
</p>
<p>The filters accept the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>in</samp>&rsquo;</dt>
<dd><p>Set stereoscopic image format of input.
</p>
<p>Available values for input image formats are:
</p><dl compact="compact">
<dt> &lsquo;<samp>sbsl</samp>&rsquo;</dt>
<dd><p>side by side parallel (left eye left, right eye right)
</p>
</dd>
<dt> &lsquo;<samp>sbsr</samp>&rsquo;</dt>
<dd><p>side by side crosseye (right eye left, left eye right)
</p>
</dd>
<dt> &lsquo;<samp>sbs2l</samp>&rsquo;</dt>
<dd><p>side by side parallel with half width resolution
(left eye left, right eye right)
</p>
</dd>
<dt> &lsquo;<samp>sbs2r</samp>&rsquo;</dt>
<dd><p>side by side crosseye with half width resolution
(right eye left, left eye right)
</p>
</dd>
<dt> &lsquo;<samp>abl</samp>&rsquo;</dt>
<dd><p>above-below (left eye above, right eye below)
</p>
</dd>
<dt> &lsquo;<samp>abr</samp>&rsquo;</dt>
<dd><p>above-below (right eye above, left eye below)
</p>
</dd>
<dt> &lsquo;<samp>ab2l</samp>&rsquo;</dt>
<dd><p>above-below with half height resolution
(left eye above, right eye below)
</p>
</dd>
<dt> &lsquo;<samp>ab2r</samp>&rsquo;</dt>
<dd><p>above-below with half height resolution
(right eye above, left eye below)
</p>
</dd>
<dt> &lsquo;<samp>al</samp>&rsquo;</dt>
<dd><p>alternating frames (left eye first, right eye second)
</p>
</dd>
<dt> &lsquo;<samp>ar</samp>&rsquo;</dt>
<dd><p>alternating frames (right eye first, left eye second)
</p>
<p>Default value is &lsquo;<samp>sbsl</samp>&rsquo;.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>out</samp>&rsquo;</dt>
<dd><p>Set stereoscopic image format of output.
</p>
<p>Available values for output image formats are all the input formats as well as:
</p><dl compact="compact">
<dt> &lsquo;<samp>arbg</samp>&rsquo;</dt>
<dd><p>anaglyph red/blue gray
(red filter on left eye, blue filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>argg</samp>&rsquo;</dt>
<dd><p>anaglyph red/green gray
(red filter on left eye, green filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>arcg</samp>&rsquo;</dt>
<dd><p>anaglyph red/cyan gray
(red filter on left eye, cyan filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>arch</samp>&rsquo;</dt>
<dd><p>anaglyph red/cyan half colored
(red filter on left eye, cyan filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>arcc</samp>&rsquo;</dt>
<dd><p>anaglyph red/cyan color
(red filter on left eye, cyan filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>arcd</samp>&rsquo;</dt>
<dd><p>anaglyph red/cyan color optimized with the least squares projection of dubois
(red filter on left eye, cyan filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>agmg</samp>&rsquo;</dt>
<dd><p>anaglyph green/magenta gray
(green filter on left eye, magenta filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>agmh</samp>&rsquo;</dt>
<dd><p>anaglyph green/magenta half colored
(green filter on left eye, magenta filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>agmc</samp>&rsquo;</dt>
<dd><p>anaglyph green/magenta colored
(green filter on left eye, magenta filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>agmd</samp>&rsquo;</dt>
<dd><p>anaglyph green/magenta color optimized with the least squares projection of dubois
(green filter on left eye, magenta filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>aybg</samp>&rsquo;</dt>
<dd><p>anaglyph yellow/blue gray
(yellow filter on left eye, blue filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>aybh</samp>&rsquo;</dt>
<dd><p>anaglyph yellow/blue half colored
(yellow filter on left eye, blue filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>aybc</samp>&rsquo;</dt>
<dd><p>anaglyph yellow/blue colored
(yellow filter on left eye, blue filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>aybd</samp>&rsquo;</dt>
<dd><p>anaglyph yellow/blue color optimized with the least squares projection of dubois
(yellow filter on left eye, blue filter on right eye)
</p>
</dd>
<dt> &lsquo;<samp>irl</samp>&rsquo;</dt>
<dd><p>interleaved rows (left eye has top row, right eye starts on next row)
</p>
</dd>
<dt> &lsquo;<samp>irr</samp>&rsquo;</dt>
<dd><p>interleaved rows (right eye has top row, left eye starts on next row)
</p>
</dd>
<dt> &lsquo;<samp>ml</samp>&rsquo;</dt>
<dd><p>mono output (left eye only)
</p>
</dd>
<dt> &lsquo;<samp>mr</samp>&rsquo;</dt>
<dd><p>mono output (right eye only)
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>arcd</samp>&rsquo;.
</p></dd>
</dl>
<a name="Examples-83"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-83">28.79.1 Examples</a></h3>
<ul>
<li>
Convert input video from side by side parallel to anaglyph yellow/blue dubois:
<table><tr><td>&nbsp;</td><td><pre class="example">stereo3d=sbsl:aybd
</pre></td></tr></table>
</li><li>
Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
<table><tr><td>&nbsp;</td><td><pre class="example">stereo3d=abl:sbsr
</pre></td></tr></table>
</li></ul>
<a name="spp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-spp">28.80 spp</a></h2>
<p>Apply a simple postprocessing filter that compresses and decompresses the image
at several (or - in the case of &lsquo;<samp>quality</samp>&rsquo; level <code>6</code> - all) shifts
and average the results.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>quality</samp>&rsquo;</dt>
<dd><p>Set quality. This option defines the number of levels for averaging. It accepts
an integer in the range 0-6. If set to <code>0</code>, the filter will have no
effect. A value of <code>6</code> means the higher quality. For each increment of
that value the speed drops by a factor of approximately 2. Default value is
<code>3</code>.
</p>
</dd>
<dt> &lsquo;<samp>qp</samp>&rsquo;</dt>
<dd><p>Force a constant quantization parameter. If not set, the filter will use the QP
from the video stream (if available).
</p>
</dd>
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set thresholding mode. Available modes are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>hard</samp>&rsquo;</dt>
<dd><p>Set hard thresholding (default).
</p></dd>
<dt> &lsquo;<samp>soft</samp>&rsquo;</dt>
<dd><p>Set soft thresholding (better de-ringing effect, but likely blurrier).
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>use_bframe_qp</samp>&rsquo;</dt>
<dd><p>Enable the use of the QP from the B-Frames if set to <code>1</code>. Using this
option may cause flicker since the B-Frames have often larger QP. Default is
<code>0</code> (not enabled).
</p></dd>
</dl>
<p><a name="subtitles"></a>
</p><a name="subtitles-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-subtitles-1">28.81 subtitles</a></h2>
<p>Draw subtitles on top of input video using the libass library.
</p>
<p>To enable compilation of this filter you need to configure FFmpeg with
<code>--enable-libass</code>. This filter also requires a build with libavcodec and
libavformat to convert the passed subtitles file to ASS (Advanced Substation
Alpha) subtitles format.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filename, f</samp>&rsquo;</dt>
<dd><p>Set the filename of the subtitle file to read. It must be specified.
</p>
</dd>
<dt> &lsquo;<samp>original_size</samp>&rsquo;</dt>
<dd><p>Specify the size of the original video, the video for which the ASS file
was composed. For the syntax of this option, check the &quot;Video size&quot; section in
the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
this is necessary to correctly scale the fonts if the aspect ratio has been
changed.
</p>
</dd>
<dt> &lsquo;<samp>charenc</samp>&rsquo;</dt>
<dd><p>Set subtitles input character encoding. <code>subtitles</code> filter only. Only
useful if not UTF-8.
</p></dd>
</dl>
<p>If the first key is not specified, it is assumed that the first value
specifies the &lsquo;<samp>filename</samp>&rsquo;.
</p>
<p>For example, to render the file &lsquo;<tt>sub.srt</tt>&rsquo; on top of the input
video, use the command:
</p><table><tr><td>&nbsp;</td><td><pre class="example">subtitles=sub.srt
</pre></td></tr></table>
<p>which is equivalent to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">subtitles=filename=sub.srt
</pre></td></tr></table>
<a name="super2xsai"></a>
<h2 class="section"><a href="ffplay-all.html#toc-super2xsai">28.82 super2xsai</a></h2>
<p>Scale the input by 2x and smooth using the Super2xSaI (Scale and
Interpolate) pixel art scaling algorithm.
</p>
<p>Useful for enlarging pixel art images without reducing sharpness.
</p>
<a name="swapuv"></a>
<h2 class="section"><a href="ffplay-all.html#toc-swapuv">28.83 swapuv</a></h2>
<p>Swap U &amp; V plane.
</p>
<a name="telecine"></a>
<h2 class="section"><a href="ffplay-all.html#toc-telecine">28.84 telecine</a></h2>
<p>Apply telecine process to the video.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>first_field</samp>&rsquo;</dt>
<dd><dl compact="compact">
<dt> &lsquo;<samp>top, t</samp>&rsquo;</dt>
<dd><p>top field first
</p></dd>
<dt> &lsquo;<samp>bottom, b</samp>&rsquo;</dt>
<dd><p>bottom field first
The default value is <code>top</code>.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>pattern</samp>&rsquo;</dt>
<dd><p>A string of numbers representing the pulldown pattern you wish to apply.
The default value is <code>23</code>.
</p></dd>
</dl>
<table><tr><td>&nbsp;</td><td><pre class="example">Some typical patterns:
NTSC output (30i):
27.5p: 32222
24p: 23 (classic)
24p: 2332 (preferred)
20p: 33
18p: 334
16p: 3444
PAL output (25i):
27.5p: 12222
24p: 222222222223 (&quot;Euro pulldown&quot;)
16.67p: 33
16p: 33333334
</pre></td></tr></table>
<a name="thumbnail"></a>
<h2 class="section"><a href="ffplay-all.html#toc-thumbnail">28.85 thumbnail</a></h2>
<p>Select the most representative frame in a given sequence of consecutive frames.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>Set the frames batch size to analyze; in a set of <var>n</var> frames, the filter
will pick one of them, and then handle the next batch of <var>n</var> frames until
the end. Default is <code>100</code>.
</p></dd>
</dl>
<p>Since the filter keeps track of the whole frames sequence, a bigger <var>n</var>
value will result in a higher memory usage, so a high value is not recommended.
</p>
<a name="Examples-60"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-60">28.85.1 Examples</a></h3>
<ul>
<li>
Extract one picture each 50 frames:
<table><tr><td>&nbsp;</td><td><pre class="example">thumbnail=50
</pre></td></tr></table>
</li><li>
Complete example of a thumbnail creation with <code>ffmpeg</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
</pre></td></tr></table>
</li></ul>
<a name="tile"></a>
<h2 class="section"><a href="ffplay-all.html#toc-tile">28.86 tile</a></h2>
<p>Tile several successive frames together.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>layout</samp>&rsquo;</dt>
<dd><p>Set the grid size (i.e. the number of lines and columns). For the syntax of
this option, check the &quot;Video size&quot; section in the ffmpeg-utils manual.
</p>
</dd>
<dt> &lsquo;<samp>nb_frames</samp>&rsquo;</dt>
<dd><p>Set the maximum number of frames to render in the given area. It must be less
than or equal to <var>w</var>x<var>h</var>. The default value is <code>0</code>, meaning all
the area will be used.
</p>
</dd>
<dt> &lsquo;<samp>margin</samp>&rsquo;</dt>
<dd><p>Set the outer border margin in pixels.
</p>
</dd>
<dt> &lsquo;<samp>padding</samp>&rsquo;</dt>
<dd><p>Set the inner border thickness (i.e. the number of pixels between frames). For
more advanced padding options (such as having different values for the edges),
refer to the pad video filter.
</p>
</dd>
<dt> &lsquo;<samp>color</samp>&rsquo;</dt>
<dd><p>Specify the color of the unused areaFor the syntax of this option, check the
&quot;Color&quot; section in the ffmpeg-utils manual. The default value of <var>color</var>
is &quot;black&quot;.
</p></dd>
</dl>
<a name="Examples-75"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-75">28.86.1 Examples</a></h3>
<ul>
<li>
Produce 8x8 PNG tiles of all keyframes (&lsquo;<samp>-skip_frame nokey</samp>&rsquo;) in a movie:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
</pre></td></tr></table>
<p>The &lsquo;<samp>-vsync 0</samp>&rsquo; is necessary to prevent <code>ffmpeg</code> from
duplicating each output frame to accommodate the originally detected frame
rate.
</p>
</li><li>
Display <code>5</code> pictures in an area of <code>3x2</code> frames,
with <code>7</code> pixels between them, and <code>2</code> pixels of initial margin, using
mixed flat and named options:
<table><tr><td>&nbsp;</td><td><pre class="example">tile=3x2:nb_frames=5:padding=7:margin=2
</pre></td></tr></table>
</li></ul>
<a name="tinterlace"></a>
<h2 class="section"><a href="ffplay-all.html#toc-tinterlace">28.87 tinterlace</a></h2>
<p>Perform various types of temporal field interlacing.
</p>
<p>Frames are counted starting from 1, so the first input frame is
considered odd.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Specify the mode of the interlacing. This option can also be specified
as a value alone. See below for a list of values for this option.
</p>
<p>Available values are:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>merge, 0</samp>&rsquo;</dt>
<dd><p>Move odd frames into the upper field, even into the lower field,
generating a double height frame at half frame rate.
</p>
</dd>
<dt> &lsquo;<samp>drop_odd, 1</samp>&rsquo;</dt>
<dd><p>Only output even frames, odd frames are dropped, generating a frame with
unchanged height at half frame rate.
</p>
</dd>
<dt> &lsquo;<samp>drop_even, 2</samp>&rsquo;</dt>
<dd><p>Only output odd frames, even frames are dropped, generating a frame with
unchanged height at half frame rate.
</p>
</dd>
<dt> &lsquo;<samp>pad, 3</samp>&rsquo;</dt>
<dd><p>Expand each frame to full height, but pad alternate lines with black,
generating a frame with double height at the same input frame rate.
</p>
</dd>
<dt> &lsquo;<samp>interleave_top, 4</samp>&rsquo;</dt>
<dd><p>Interleave the upper field from odd frames with the lower field from
even frames, generating a frame with unchanged height at half frame rate.
</p>
</dd>
<dt> &lsquo;<samp>interleave_bottom, 5</samp>&rsquo;</dt>
<dd><p>Interleave the lower field from odd frames with the upper field from
even frames, generating a frame with unchanged height at half frame rate.
</p>
</dd>
<dt> &lsquo;<samp>interlacex2, 6</samp>&rsquo;</dt>
<dd><p>Double frame rate with unchanged height. Frames are inserted each
containing the second temporal field from the previous input frame and
the first temporal field from the next input frame. This mode relies on
the top_field_first flag. Useful for interlaced video displays with no
field synchronisation.
</p></dd>
</dl>
<p>Numeric values are deprecated but are accepted for backward
compatibility reasons.
</p>
<p>Default mode is <code>merge</code>.
</p>
</dd>
<dt> &lsquo;<samp>flags</samp>&rsquo;</dt>
<dd><p>Specify flags influencing the filter process.
</p>
<p>Available value for <var>flags</var> is:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>low_pass_filter, vlfp</samp>&rsquo;</dt>
<dd><p>Enable vertical low-pass filtering in the filter.
Vertical low-pass filtering is required when creating an interlaced
destination from a progressive source which contains high-frequency
vertical detail. Filtering will reduce interlace &rsquo;twitter&rsquo; and Moire
patterning.
</p>
<p>Vertical low-pass filtering can only be enabled for &lsquo;<samp>mode</samp>&rsquo;
<var>interleave_top</var> and <var>interleave_bottom</var>.
</p>
</dd>
</dl>
</dd>
</dl>
<a name="transpose"></a>
<h2 class="section"><a href="ffplay-all.html#toc-transpose">28.88 transpose</a></h2>
<p>Transpose rows with columns in the input video and optionally flip it.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>dir</samp>&rsquo;</dt>
<dd><p>Specify the transposition direction.
</p>
<p>Can assume the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>0, 4, cclock_flip</samp>&rsquo;</dt>
<dd><p>Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">L.R L.l
. . -&gt; . .
l.r R.r
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>1, 5, clock</samp>&rsquo;</dt>
<dd><p>Rotate by 90 degrees clockwise, that is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">L.R l.L
. . -&gt; . .
l.r r.R
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>2, 6, cclock</samp>&rsquo;</dt>
<dd><p>Rotate by 90 degrees counterclockwise, that is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">L.R R.r
. . -&gt; . .
l.r L.l
</pre></td></tr></table>
</dd>
<dt> &lsquo;<samp>3, 7, clock_flip</samp>&rsquo;</dt>
<dd><p>Rotate by 90 degrees clockwise and vertically flip, that is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">L.R r.R
. . -&gt; . .
l.r l.L
</pre></td></tr></table>
</dd>
</dl>
<p>For values between 4-7, the transposition is only done if the input
video geometry is portrait and not landscape. These values are
deprecated, the <code>passthrough</code> option should be used instead.
</p>
<p>Numerical values are deprecated, and should be dropped in favor of
symbolic constants.
</p>
</dd>
<dt> &lsquo;<samp>passthrough</samp>&rsquo;</dt>
<dd><p>Do not apply the transposition if the input geometry matches the one
specified by the specified value. It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>Always apply transposition.
</p></dd>
<dt> &lsquo;<samp>portrait</samp>&rsquo;</dt>
<dd><p>Preserve portrait geometry (when <var>height</var> &gt;= <var>width</var>).
</p></dd>
<dt> &lsquo;<samp>landscape</samp>&rsquo;</dt>
<dd><p>Preserve landscape geometry (when <var>width</var> &gt;= <var>height</var>).
</p></dd>
</dl>
<p>Default value is <code>none</code>.
</p></dd>
</dl>
<p>For example to rotate by 90 degrees clockwise and preserve portrait
layout:
</p><table><tr><td>&nbsp;</td><td><pre class="example">transpose=dir=1:passthrough=portrait
</pre></td></tr></table>
<p>The command above can also be specified as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">transpose=1:portrait
</pre></td></tr></table>
<a name="trim"></a>
<h2 class="section"><a href="ffplay-all.html#toc-trim">28.89 trim</a></h2>
<p>Trim the input so that the output contains one continuous subpart of the input.
</p>
<p>This filter accepts the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>start</samp>&rsquo;</dt>
<dd><p>Specify time of the start of the kept section, i.e. the frame with the
timestamp <var>start</var> will be the first frame in the output.
</p>
</dd>
<dt> &lsquo;<samp>end</samp>&rsquo;</dt>
<dd><p>Specify time of the first frame that will be dropped, i.e. the frame
immediately preceding the one with the timestamp <var>end</var> will be the last
frame in the output.
</p>
</dd>
<dt> &lsquo;<samp>start_pts</samp>&rsquo;</dt>
<dd><p>Same as <var>start</var>, except this option sets the start timestamp in timebase
units instead of seconds.
</p>
</dd>
<dt> &lsquo;<samp>end_pts</samp>&rsquo;</dt>
<dd><p>Same as <var>end</var>, except this option sets the end timestamp in timebase units
instead of seconds.
</p>
</dd>
<dt> &lsquo;<samp>duration</samp>&rsquo;</dt>
<dd><p>Specify maximum duration of the output.
</p>
</dd>
<dt> &lsquo;<samp>start_frame</samp>&rsquo;</dt>
<dd><p>Number of the first frame that should be passed to output.
</p>
</dd>
<dt> &lsquo;<samp>end_frame</samp>&rsquo;</dt>
<dd><p>Number of the first frame that should be dropped.
</p></dd>
</dl>
<p>&lsquo;<samp>start</samp>&rsquo;, &lsquo;<samp>end</samp>&rsquo;, &lsquo;<samp>duration</samp>&rsquo; are expressed as time
duration specifications, check the &quot;Time duration&quot; section in the
ffmpeg-utils manual.
</p>
<p>Note that the first two sets of the start/end options and the &lsquo;<samp>duration</samp>&rsquo;
option look at the frame timestamp, while the _frame variants simply count the
frames that pass through the filter. Also note that this filter does not modify
the timestamps. If you wish that the output timestamps start at zero, insert a
setpts filter after the trim filter.
</p>
<p>If multiple start or end options are set, this filter tries to be greedy and
keep all the frames that match at least one of the specified constraints. To keep
only the part that matches all the constraints at once, chain multiple trim
filters.
</p>
<p>The defaults are such that all the input is kept. So it is possible to set e.g.
just the end values to keep everything before the specified time.
</p>
<p>Examples:
</p><ul>
<li>
drop everything except the second minute of input
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -vf trim=60:120
</pre></td></tr></table>
</li><li>
keep only the first second
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -vf trim=duration=1
</pre></td></tr></table>
</li></ul>
<a name="unsharp"></a>
<h2 class="section"><a href="ffplay-all.html#toc-unsharp">28.90 unsharp</a></h2>
<p>Sharpen or blur the input video.
</p>
<p>It accepts the following parameters:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>luma_msize_x, lx</samp>&rsquo;</dt>
<dd><p>Set the luma matrix horizontal size. It must be an odd integer between
3 and 63, default value is 5.
</p>
</dd>
<dt> &lsquo;<samp>luma_msize_y, ly</samp>&rsquo;</dt>
<dd><p>Set the luma matrix vertical size. It must be an odd integer between 3
and 63, default value is 5.
</p>
</dd>
<dt> &lsquo;<samp>luma_amount, la</samp>&rsquo;</dt>
<dd><p>Set the luma effect strength. It can be a float number, reasonable
values lay between -1.5 and 1.5.
</p>
<p>Negative values will blur the input video, while positive values will
sharpen it, a value of zero will disable the effect.
</p>
<p>Default value is 1.0.
</p>
</dd>
<dt> &lsquo;<samp>chroma_msize_x, cx</samp>&rsquo;</dt>
<dd><p>Set the chroma matrix horizontal size. It must be an odd integer
between 3 and 63, default value is 5.
</p>
</dd>
<dt> &lsquo;<samp>chroma_msize_y, cy</samp>&rsquo;</dt>
<dd><p>Set the chroma matrix vertical size. It must be an odd integer
between 3 and 63, default value is 5.
</p>
</dd>
<dt> &lsquo;<samp>chroma_amount, ca</samp>&rsquo;</dt>
<dd><p>Set the chroma effect strength. It can be a float number, reasonable
values lay between -1.5 and 1.5.
</p>
<p>Negative values will blur the input video, while positive values will
sharpen it, a value of zero will disable the effect.
</p>
<p>Default value is 0.0.
</p>
</dd>
<dt> &lsquo;<samp>opencl</samp>&rsquo;</dt>
<dd><p>If set to 1, specify using OpenCL capabilities, only available if
FFmpeg was configured with <code>--enable-opencl</code>. Default value is 0.
</p>
</dd>
</dl>
<p>All parameters are optional and default to the equivalent of the
string &rsquo;5:5:1.0:5:5:0.0&rsquo;.
</p>
<a name="Examples-15"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-15">28.90.1 Examples</a></h3>
<ul>
<li>
Apply strong luma sharpen effect:
<table><tr><td>&nbsp;</td><td><pre class="example">unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
</pre></td></tr></table>
</li><li>
Apply strong blur of both luma and chroma parameters:
<table><tr><td>&nbsp;</td><td><pre class="example">unsharp=7:7:-2:7:7:-2
</pre></td></tr></table>
</li></ul>
<p><a name="vidstabdetect"></a>
</p><a name="vidstabdetect-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-vidstabdetect-1">28.91 vidstabdetect</a></h2>
<p>Analyze video stabilization/deshaking. Perform pass 1 of 2, see
<a href="#vidstabtransform">vidstabtransform</a> for pass 2.
</p>
<p>This filter generates a file with relative translation and rotation
transform information about subsequent frames, which is then used by
the <a href="#vidstabtransform">vidstabtransform</a> filter.
</p>
<p>To enable compilation of this filter you need to configure FFmpeg with
<code>--enable-libvidstab</code>.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>result</samp>&rsquo;</dt>
<dd><p>Set the path to the file used to write the transforms information.
Default value is &lsquo;<tt>transforms.trf</tt>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>shakiness</samp>&rsquo;</dt>
<dd><p>Set how shaky the video is and how quick the camera is. It accepts an
integer in the range 1-10, a value of 1 means little shakiness, a
value of 10 means strong shakiness. Default value is 5.
</p>
</dd>
<dt> &lsquo;<samp>accuracy</samp>&rsquo;</dt>
<dd><p>Set the accuracy of the detection process. It must be a value in the
range 1-15. A value of 1 means low accuracy, a value of 15 means high
accuracy. Default value is 15.
</p>
</dd>
<dt> &lsquo;<samp>stepsize</samp>&rsquo;</dt>
<dd><p>Set stepsize of the search process. The region around minimum is
scanned with 1 pixel resolution. Default value is 6.
</p>
</dd>
<dt> &lsquo;<samp>mincontrast</samp>&rsquo;</dt>
<dd><p>Set minimum contrast. Below this value a local measurement field is
discarded. Must be a floating point value in the range 0-1. Default
value is 0.3.
</p>
</dd>
<dt> &lsquo;<samp>tripod</samp>&rsquo;</dt>
<dd><p>Set reference frame number for tripod mode.
</p>
<p>If enabled, the motion of the frames is compared to a reference frame
in the filtered stream, identified by the specified number. The idea
is to compensate all movements in a more-or-less static scene and keep
the camera view absolutely still.
</p>
<p>If set to 0, it is disabled. The frames are counted starting from 1.
</p>
</dd>
<dt> &lsquo;<samp>show</samp>&rsquo;</dt>
<dd><p>Show fields and transforms in the resulting frames. It accepts an
integer in the range 0-2. Default value is 0, which disables any
visualization.
</p></dd>
</dl>
<a name="Examples-64"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-64">28.91.1 Examples</a></h3>
<ul>
<li>
Use default values:
<table><tr><td>&nbsp;</td><td><pre class="example">vidstabdetect
</pre></td></tr></table>
</li><li>
Analyze strongly shaky movie and put the results in file
&lsquo;<tt>mytransforms.trf</tt>&rsquo;:
<table><tr><td>&nbsp;</td><td><pre class="example">vidstabdetect=shakiness=10:accuracy=15:result=&quot;mytransforms.trf&quot;
</pre></td></tr></table>
</li><li>
Visualize the result of internal transformations in the resulting
video:
<table><tr><td>&nbsp;</td><td><pre class="example">vidstabdetect=show=1
</pre></td></tr></table>
</li><li>
Analyze a video with medium shakiness using <code>ffmpeg</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
</pre></td></tr></table>
</li></ul>
<p><a name="vidstabtransform"></a>
</p><a name="vidstabtransform-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-vidstabtransform-1">28.92 vidstabtransform</a></h2>
<p>Video stabilization/deshaking: pass 2 of 2,
see <a href="#vidstabdetect">vidstabdetect</a> for pass 1.
</p>
<p>Read a file with transform information for each frame and
apply/compensate them. Together with the <a href="#vidstabdetect">vidstabdetect</a>
filter this can be used to deshake videos. See also
<a href="http://public.hronopik.de/vid.stab">http://public.hronopik.de/vid.stab</a>. It is important to also use
the unsharp filter, see below.
</p>
<p>To enable compilation of this filter you need to configure FFmpeg with
<code>--enable-libvidstab</code>.
</p>
<a name="Options-10"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Options-10">28.92.1 Options</a></h3>
<dl compact="compact">
<dt> &lsquo;<samp>input</samp>&rsquo;</dt>
<dd><p>Set path to the file used to read the transforms. Default value is
&lsquo;<tt>transforms.trf</tt>&rsquo;).
</p>
</dd>
<dt> &lsquo;<samp>smoothing</samp>&rsquo;</dt>
<dd><p>Set the number of frames (value*2 + 1) used for lowpass filtering the
camera movements. Default value is 10.
</p>
<p>For example a number of 10 means that 21 frames are used (10 in the
past and 10 in the future) to smoothen the motion in the video. A
larger values leads to a smoother video, but limits the acceleration
of the camera (pan/tilt movements). 0 is a special case where a
static camera is simulated.
</p>
</dd>
<dt> &lsquo;<samp>optalgo</samp>&rsquo;</dt>
<dd><p>Set the camera path optimization algorithm.
</p>
<p>Accepted values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>gauss</samp>&rsquo;</dt>
<dd><p>gaussian kernel low-pass filter on camera motion (default)
</p></dd>
<dt> &lsquo;<samp>avg</samp>&rsquo;</dt>
<dd><p>averaging on transformations
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>maxshift</samp>&rsquo;</dt>
<dd><p>Set maximal number of pixels to translate frames. Default value is -1,
meaning no limit.
</p>
</dd>
<dt> &lsquo;<samp>maxangle</samp>&rsquo;</dt>
<dd><p>Set maximal angle in radians (degree*PI/180) to rotate frames. Default
value is -1, meaning no limit.
</p>
</dd>
<dt> &lsquo;<samp>crop</samp>&rsquo;</dt>
<dd><p>Specify how to deal with borders that may be visible due to movement
compensation.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>keep</samp>&rsquo;</dt>
<dd><p>keep image information from previous frame (default)
</p></dd>
<dt> &lsquo;<samp>black</samp>&rsquo;</dt>
<dd><p>fill the border black
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>invert</samp>&rsquo;</dt>
<dd><p>Invert transforms if set to 1. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>relative</samp>&rsquo;</dt>
<dd><p>Consider transforms as relative to previsou frame if set to 1,
absolute if set to 0. Default value is 0.
</p>
</dd>
<dt> &lsquo;<samp>zoom</samp>&rsquo;</dt>
<dd><p>Set percentage to zoom. A positive value will result in a zoom-in
effect, a negative value in a zoom-out effect. Default value is 0 (no
zoom).
</p>
</dd>
<dt> &lsquo;<samp>optzoom</samp>&rsquo;</dt>
<dd><p>Set optimal zooming to avoid borders.
</p>
<p>Accepted values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>0</samp>&rsquo;</dt>
<dd><p>disabled
</p></dd>
<dt> &lsquo;<samp>1</samp>&rsquo;</dt>
<dd><p>optimal static zoom value is determined (only very strong movements
will lead to visible borders) (default)
</p></dd>
<dt> &lsquo;<samp>2</samp>&rsquo;</dt>
<dd><p>optimal adaptive zoom value is determined (no borders will be
visible), see &lsquo;<samp>zoomspeed</samp>&rsquo;
</p></dd>
</dl>
<p>Note that the value given at zoom is added to the one calculated here.
</p>
</dd>
<dt> &lsquo;<samp>zoomspeed</samp>&rsquo;</dt>
<dd><p>Set percent to zoom maximally each frame (enabled when
&lsquo;<samp>optzoom</samp>&rsquo; is set to 2). Range is from 0 to 5, default value is
0.25.
</p>
</dd>
<dt> &lsquo;<samp>interpol</samp>&rsquo;</dt>
<dd><p>Specify type of interpolation.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>no</samp>&rsquo;</dt>
<dd><p>no interpolation
</p></dd>
<dt> &lsquo;<samp>linear</samp>&rsquo;</dt>
<dd><p>linear only horizontal
</p></dd>
<dt> &lsquo;<samp>bilinear</samp>&rsquo;</dt>
<dd><p>linear in both directions (default)
</p></dd>
<dt> &lsquo;<samp>bicubic</samp>&rsquo;</dt>
<dd><p>cubic in both directions (slow)
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>tripod</samp>&rsquo;</dt>
<dd><p>Enable virtual tripod mode if set to 1, which is equivalent to
<code>relative=0:smoothing=0</code>. Default value is 0.
</p>
<p>Use also <code>tripod</code> option of <a href="#vidstabdetect">vidstabdetect</a>.
</p>
</dd>
<dt> &lsquo;<samp>debug</samp>&rsquo;</dt>
<dd><p>Increase log verbosity if set to 1. Also the detected global motions
are written to the temporary file &lsquo;<tt>global_motions.trf</tt>&rsquo;. Default
value is 0.
</p></dd>
</dl>
<a name="Examples-14"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-14">28.92.2 Examples</a></h3>
<ul>
<li>
Use <code>ffmpeg</code> for a typical stabilization with default values:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
</pre></td></tr></table>
<p>Note the use of the unsharp filter which is always recommended.
</p>
</li><li>
Zoom in a bit more and load transform data from a given file:
<table><tr><td>&nbsp;</td><td><pre class="example">vidstabtransform=zoom=5:input=&quot;mytransforms.trf&quot;
</pre></td></tr></table>
</li><li>
Smoothen the video even more:
<table><tr><td>&nbsp;</td><td><pre class="example">vidstabtransform=smoothing=30
</pre></td></tr></table>
</li></ul>
<a name="vflip"></a>
<h2 class="section"><a href="ffplay-all.html#toc-vflip">28.93 vflip</a></h2>
<p>Flip the input video vertically.
</p>
<p>For example, to vertically flip a video with <code>ffmpeg</code>:
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i in.avi -vf &quot;vflip&quot; out.avi
</pre></td></tr></table>
<a name="vignette"></a>
<h2 class="section"><a href="ffplay-all.html#toc-vignette">28.94 vignette</a></h2>
<p>Make or reverse a natural vignetting effect.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>angle, a</samp>&rsquo;</dt>
<dd><p>Set lens angle expression as a number of radians.
</p>
<p>The value is clipped in the <code>[0,PI/2]</code> range.
</p>
<p>Default value: <code>&quot;PI/5&quot;</code>
</p>
</dd>
<dt> &lsquo;<samp>x0</samp>&rsquo;</dt>
<dt> &lsquo;<samp>y0</samp>&rsquo;</dt>
<dd><p>Set center coordinates expressions. Respectively <code>&quot;w/2&quot;</code> and <code>&quot;h/2&quot;</code>
by default.
</p>
</dd>
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set forward/backward mode.
</p>
<p>Available modes are:
</p><dl compact="compact">
<dt> &lsquo;<samp>forward</samp>&rsquo;</dt>
<dd><p>The larger the distance from the central point, the darker the image becomes.
</p>
</dd>
<dt> &lsquo;<samp>backward</samp>&rsquo;</dt>
<dd><p>The larger the distance from the central point, the brighter the image becomes.
This can be used to reverse a vignette effect, though there is no automatic
detection to extract the lens &lsquo;<samp>angle</samp>&rsquo; and other settings (yet). It can
also be used to create a burning effect.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>forward</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>eval</samp>&rsquo;</dt>
<dd><p>Set evaluation mode for the expressions (&lsquo;<samp>angle</samp>&rsquo;, &lsquo;<samp>x0</samp>&rsquo;, &lsquo;<samp>y0</samp>&rsquo;).
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>init</samp>&rsquo;</dt>
<dd><p>Evaluate expressions only once during the filter initialization.
</p>
</dd>
<dt> &lsquo;<samp>frame</samp>&rsquo;</dt>
<dd><p>Evaluate expressions for each incoming frame. This is way slower than the
&lsquo;<samp>init</samp>&rsquo; mode since it requires all the scalers to be re-computed, but it
allows advanced dynamic expressions.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>init</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>dither</samp>&rsquo;</dt>
<dd><p>Set dithering to reduce the circular banding effects. Default is <code>1</code>
(enabled).
</p>
</dd>
<dt> &lsquo;<samp>aspect</samp>&rsquo;</dt>
<dd><p>Set vignette aspect. This setting allows one to adjust the shape of the vignette.
Setting this value to the SAR of the input will make a rectangular vignetting
following the dimensions of the video.
</p>
<p>Default is <code>1/1</code>.
</p></dd>
</dl>
<a name="Expressions"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Expressions">28.94.1 Expressions</a></h3>
<p>The &lsquo;<samp>alpha</samp>&rsquo;, &lsquo;<samp>x0</samp>&rsquo; and &lsquo;<samp>y0</samp>&rsquo; expressions can contain the
following parameters.
</p>
<dl compact="compact">
<dt> &lsquo;<samp>w</samp>&rsquo;</dt>
<dt> &lsquo;<samp>h</samp>&rsquo;</dt>
<dd><p>input width and height
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>the number of input frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dd><p>the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
<var>TB</var> units, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>r</samp>&rsquo;</dt>
<dd><p>frame rate of the input video, NAN if the input frame rate is unknown
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>the PTS (Presentation TimeStamp) of the filtered video frame,
expressed in seconds, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>tb</samp>&rsquo;</dt>
<dd><p>time base of the input video
</p></dd>
</dl>
<a name="Examples-80"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-80">28.94.2 Examples</a></h3>
<ul>
<li>
Apply simple strong vignetting effect:
<table><tr><td>&nbsp;</td><td><pre class="example">vignette=PI/4
</pre></td></tr></table>
</li><li>
Make a flickering vignetting:
<table><tr><td>&nbsp;</td><td><pre class="example">vignette='PI/4+random(1)*PI/50':eval=frame
</pre></td></tr></table>
</li></ul>
<a name="w3fdif"></a>
<h2 class="section"><a href="ffplay-all.html#toc-w3fdif">28.95 w3fdif</a></h2>
<p>Deinterlace the input video (&quot;w3fdif&quot; stands for &quot;Weston 3 Field
Deinterlacing Filter&quot;).
</p>
<p>Based on the process described by Martin Weston for BBC R&amp;D, and
implemented based on the de-interlace algorithm written by Jim
Easterbrook for BBC R&amp;D, the Weston 3 field deinterlacing filter
uses filter coefficients calculated by BBC R&amp;D.
</p>
<p>There are two sets of filter coefficients, so called &quot;simple&quot;:
and &quot;complex&quot;. Which set of filter coefficients is used can
be set by passing an optional parameter:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filter</samp>&rsquo;</dt>
<dd><p>Set the interlacing filter coefficients. Accepts one of the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>simple</samp>&rsquo;</dt>
<dd><p>Simple filter coefficient set.
</p></dd>
<dt> &lsquo;<samp>complex</samp>&rsquo;</dt>
<dd><p>More-complex filter coefficient set.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>complex</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>deint</samp>&rsquo;</dt>
<dd><p>Specify which frames to deinterlace. Accept one of the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Deinterlace all frames,
</p></dd>
<dt> &lsquo;<samp>interlaced</samp>&rsquo;</dt>
<dd><p>Only deinterlace frames marked as interlaced.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>all</samp>&rsquo;.
</p></dd>
</dl>
<p><a name="yadif"></a>
</p><a name="yadif-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-yadif-1">28.96 yadif</a></h2>
<p>Deinterlace the input video (&quot;yadif&quot; means &quot;yet another deinterlacing
filter&quot;).
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>The interlacing mode to adopt, accepts one of the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>0, send_frame</samp>&rsquo;</dt>
<dd><p>output 1 frame for each frame
</p></dd>
<dt> &lsquo;<samp>1, send_field</samp>&rsquo;</dt>
<dd><p>output 1 frame for each field
</p></dd>
<dt> &lsquo;<samp>2, send_frame_nospatial</samp>&rsquo;</dt>
<dd><p>like <code>send_frame</code> but skip spatial interlacing check
</p></dd>
<dt> &lsquo;<samp>3, send_field_nospatial</samp>&rsquo;</dt>
<dd><p>like <code>send_field</code> but skip spatial interlacing check
</p></dd>
</dl>
<p>Default value is <code>send_frame</code>.
</p>
</dd>
<dt> &lsquo;<samp>parity</samp>&rsquo;</dt>
<dd><p>The picture field parity assumed for the input interlaced video, accepts one of
the following values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>0, tff</samp>&rsquo;</dt>
<dd><p>assume top field first
</p></dd>
<dt> &lsquo;<samp>1, bff</samp>&rsquo;</dt>
<dd><p>assume bottom field first
</p></dd>
<dt> &lsquo;<samp>-1, auto</samp>&rsquo;</dt>
<dd><p>enable automatic detection
</p></dd>
</dl>
<p>Default value is <code>auto</code>.
If interlacing is unknown or decoder does not export this information,
top field first will be assumed.
</p>
</dd>
<dt> &lsquo;<samp>deint</samp>&rsquo;</dt>
<dd><p>Specify which frames to deinterlace. Accept one of the following
values:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>0, all</samp>&rsquo;</dt>
<dd><p>deinterlace all frames
</p></dd>
<dt> &lsquo;<samp>1, interlaced</samp>&rsquo;</dt>
<dd><p>only deinterlace frames marked as interlaced
</p></dd>
</dl>
<p>Default value is <code>all</code>.
</p></dd>
</dl>
<a name="Video-Sources"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Video-Sources">29. Video Sources</a></h1>
<p>Below is a description of the currently available video sources.
</p>
<a name="buffer"></a>
<h2 class="section"><a href="ffplay-all.html#toc-buffer">29.1 buffer</a></h2>
<p>Buffer video frames, and make them available to the filter chain.
</p>
<p>This source is mainly intended for a programmatic use, in particular
through the interface defined in &lsquo;<tt>libavfilter/vsrc_buffer.h</tt>&rsquo;.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>video_size</samp>&rsquo;</dt>
<dd><p>Specify the size (width and height) of the buffered video frames. For the
syntax of this option, check the &quot;Video size&quot; section in the ffmpeg-utils
manual.
</p>
</dd>
<dt> &lsquo;<samp>width</samp>&rsquo;</dt>
<dd><p>Input video width.
</p>
</dd>
<dt> &lsquo;<samp>height</samp>&rsquo;</dt>
<dd><p>Input video height.
</p>
</dd>
<dt> &lsquo;<samp>pix_fmt</samp>&rsquo;</dt>
<dd><p>A string representing the pixel format of the buffered video frames.
It may be a number corresponding to a pixel format, or a pixel format
name.
</p>
</dd>
<dt> &lsquo;<samp>time_base</samp>&rsquo;</dt>
<dd><p>Specify the timebase assumed by the timestamps of the buffered frames.
</p>
</dd>
<dt> &lsquo;<samp>frame_rate</samp>&rsquo;</dt>
<dd><p>Specify the frame rate expected for the video stream.
</p>
</dd>
<dt> &lsquo;<samp>pixel_aspect, sar</samp>&rsquo;</dt>
<dd><p>Specify the sample aspect ratio assumed by the video frames.
</p>
</dd>
<dt> &lsquo;<samp>sws_param</samp>&rsquo;</dt>
<dd><p>Specify the optional parameters to be used for the scale filter which
is automatically inserted when an input change is detected in the
input size or format.
</p></dd>
</dl>
<p>For example:
</p><table><tr><td>&nbsp;</td><td><pre class="example">buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
</pre></td></tr></table>
<p>will instruct the source to accept video frames with size 320x240 and
with format &quot;yuv410p&quot;, assuming 1/24 as the timestamps timebase and
square pixels (1:1 sample aspect ratio).
Since the pixel format with name &quot;yuv410p&quot; corresponds to the number 6
(check the enum AVPixelFormat definition in &lsquo;<tt>libavutil/pixfmt.h</tt>&rsquo;),
this example corresponds to:
</p><table><tr><td>&nbsp;</td><td><pre class="example">buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
</pre></td></tr></table>
<p>Alternatively, the options can be specified as a flat string, but this
syntax is deprecated:
</p>
<p><var>width</var>:<var>height</var>:<var>pix_fmt</var>:<var>time_base.num</var>:<var>time_base.den</var>:<var>pixel_aspect.num</var>:<var>pixel_aspect.den</var>[:<var>sws_param</var>]
</p>
<a name="cellauto"></a>
<h2 class="section"><a href="ffplay-all.html#toc-cellauto">29.2 cellauto</a></h2>
<p>Create a pattern generated by an elementary cellular automaton.
</p>
<p>The initial state of the cellular automaton can be defined through the
&lsquo;<samp>filename</samp>&rsquo;, and &lsquo;<samp>pattern</samp>&rsquo; options. If such options are
not specified an initial state is created randomly.
</p>
<p>At each new frame a new row in the video is filled with the result of
the cellular automaton next generation. The behavior when the whole
frame is filled is defined by the &lsquo;<samp>scroll</samp>&rsquo; option.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filename, f</samp>&rsquo;</dt>
<dd><p>Read the initial cellular automaton state, i.e. the starting row, from
the specified file.
In the file, each non-whitespace character is considered an alive
cell, a newline will terminate the row, and further characters in the
file will be ignored.
</p>
</dd>
<dt> &lsquo;<samp>pattern, p</samp>&rsquo;</dt>
<dd><p>Read the initial cellular automaton state, i.e. the starting row, from
the specified string.
</p>
<p>Each non-whitespace character in the string is considered an alive
cell, a newline will terminate the row, and further characters in the
string will be ignored.
</p>
</dd>
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Set the video rate, that is the number of frames generated per second.
Default is 25.
</p>
</dd>
<dt> &lsquo;<samp>random_fill_ratio, ratio</samp>&rsquo;</dt>
<dd><p>Set the random fill ratio for the initial cellular automaton row. It
is a floating point number value ranging from 0 to 1, defaults to
1/PHI.
</p>
<p>This option is ignored when a file or a pattern is specified.
</p>
</dd>
<dt> &lsquo;<samp>random_seed, seed</samp>&rsquo;</dt>
<dd><p>Set the seed for filling randomly the initial row, must be an integer
included between 0 and UINT32_MAX. If not specified, or if explicitly
set to -1, the filter will try to use a good random seed on a best
effort basis.
</p>
</dd>
<dt> &lsquo;<samp>rule</samp>&rsquo;</dt>
<dd><p>Set the cellular automaton rule, it is a number ranging from 0 to 255.
Default value is 110.
</p>
</dd>
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Set the size of the output video. For the syntax of this option, check
the &quot;Video size&quot; section in the ffmpeg-utils manual.
</p>
<p>If &lsquo;<samp>filename</samp>&rsquo; or &lsquo;<samp>pattern</samp>&rsquo; is specified, the size is set
by default to the width of the specified initial state row, and the
height is set to <var>width</var> * PHI.
</p>
<p>If &lsquo;<samp>size</samp>&rsquo; is set, it must contain the width of the specified
pattern string, and the specified pattern will be centered in the
larger row.
</p>
<p>If a filename or a pattern string is not specified, the size value
defaults to &quot;320x518&quot; (used for a randomly generated initial state).
</p>
</dd>
<dt> &lsquo;<samp>scroll</samp>&rsquo;</dt>
<dd><p>If set to 1, scroll the output upward when all the rows in the output
have been already filled. If set to 0, the new generated row will be
written over the top row just after the bottom row is filled.
Defaults to 1.
</p>
</dd>
<dt> &lsquo;<samp>start_full, full</samp>&rsquo;</dt>
<dd><p>If set to 1, completely fill the output with generated rows before
outputting the first frame.
This is the default behavior, for disabling set the value to 0.
</p>
</dd>
<dt> &lsquo;<samp>stitch</samp>&rsquo;</dt>
<dd><p>If set to 1, stitch the left and right row edges together.
This is the default behavior, for disabling set the value to 0.
</p></dd>
</dl>
<a name="Examples-38"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-38">29.2.1 Examples</a></h3>
<ul>
<li>
Read the initial state from &lsquo;<tt>pattern</tt>&rsquo;, and specify an output of
size 200x400.
<table><tr><td>&nbsp;</td><td><pre class="example">cellauto=f=pattern:s=200x400
</pre></td></tr></table>
</li><li>
Generate a random initial row with a width of 200 cells, with a fill
ratio of 2/3:
<table><tr><td>&nbsp;</td><td><pre class="example">cellauto=ratio=2/3:s=200x200
</pre></td></tr></table>
</li><li>
Create a pattern generated by rule 18 starting by a single alive cell
centered on an initial row with width 100:
<table><tr><td>&nbsp;</td><td><pre class="example">cellauto=p=@:s=100x400:full=0:rule=18
</pre></td></tr></table>
</li><li>
Specify a more elaborated initial pattern:
<table><tr><td>&nbsp;</td><td><pre class="example">cellauto=p='@@ @ @@':s=100x400:full=0:rule=18
</pre></td></tr></table>
</li></ul>
<a name="mandelbrot"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mandelbrot">29.3 mandelbrot</a></h2>
<p>Generate a Mandelbrot set fractal, and progressively zoom towards the
point specified with <var>start_x</var> and <var>start_y</var>.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>end_pts</samp>&rsquo;</dt>
<dd><p>Set the terminal pts value. Default value is 400.
</p>
</dd>
<dt> &lsquo;<samp>end_scale</samp>&rsquo;</dt>
<dd><p>Set the terminal scale value.
Must be a floating point value. Default value is 0.3.
</p>
</dd>
<dt> &lsquo;<samp>inner</samp>&rsquo;</dt>
<dd><p>Set the inner coloring mode, that is the algorithm used to draw the
Mandelbrot fractal internal region.
</p>
<p>It shall assume one of the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>black</samp>&rsquo;</dt>
<dd><p>Set black mode.
</p></dd>
<dt> &lsquo;<samp>convergence</samp>&rsquo;</dt>
<dd><p>Show time until convergence.
</p></dd>
<dt> &lsquo;<samp>mincol</samp>&rsquo;</dt>
<dd><p>Set color based on point closest to the origin of the iterations.
</p></dd>
<dt> &lsquo;<samp>period</samp>&rsquo;</dt>
<dd><p>Set period mode.
</p></dd>
</dl>
<p>Default value is <var>mincol</var>.
</p>
</dd>
<dt> &lsquo;<samp>bailout</samp>&rsquo;</dt>
<dd><p>Set the bailout value. Default value is 10.0.
</p>
</dd>
<dt> &lsquo;<samp>maxiter</samp>&rsquo;</dt>
<dd><p>Set the maximum of iterations performed by the rendering
algorithm. Default value is 7189.
</p>
</dd>
<dt> &lsquo;<samp>outer</samp>&rsquo;</dt>
<dd><p>Set outer coloring mode.
It shall assume one of following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>iteration_count</samp>&rsquo;</dt>
<dd><p>Set iteration cound mode.
</p></dd>
<dt> &lsquo;<samp>normalized_iteration_count</samp>&rsquo;</dt>
<dd><p>set normalized iteration count mode.
</p></dd>
</dl>
<p>Default value is <var>normalized_iteration_count</var>.
</p>
</dd>
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Set frame rate, expressed as number of frames per second. Default
value is &quot;25&quot;.
</p>
</dd>
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Set frame size. For the syntax of this option, check the &quot;Video
size&quot; section in the ffmpeg-utils manual. Default value is &quot;640x480&quot;.
</p>
</dd>
<dt> &lsquo;<samp>start_scale</samp>&rsquo;</dt>
<dd><p>Set the initial scale value. Default value is 3.0.
</p>
</dd>
<dt> &lsquo;<samp>start_x</samp>&rsquo;</dt>
<dd><p>Set the initial x position. Must be a floating point value between
-100 and 100. Default value is -0.743643887037158704752191506114774.
</p>
</dd>
<dt> &lsquo;<samp>start_y</samp>&rsquo;</dt>
<dd><p>Set the initial y position. Must be a floating point value between
-100 and 100. Default value is -0.131825904205311970493132056385139.
</p></dd>
</dl>
<a name="mptestsrc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-mptestsrc">29.4 mptestsrc</a></h2>
<p>Generate various test patterns, as generated by the MPlayer test filter.
</p>
<p>The size of the generated video is fixed, and is 256x256.
This source is useful in particular for testing encoding features.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Specify the frame rate of the sourced video, as the number of frames
generated per second. It has to be a string in the format
<var>frame_rate_num</var>/<var>frame_rate_den</var>, an integer number, a float
number or a valid video frame rate abbreviation. The default value is
&quot;25&quot;.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Set the video duration of the sourced video. The accepted syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[-]HH:MM:SS[.m...]
[-]S+[.m...]
</pre></td></tr></table>
<p>See also the function <code>av_parse_time()</code>.
</p>
<p>If not specified, or the expressed duration is negative, the video is
supposed to be generated forever.
</p>
</dd>
<dt> &lsquo;<samp>test, t</samp>&rsquo;</dt>
<dd>
<p>Set the number or the name of the test to perform. Supported tests are:
</p><dl compact="compact">
<dt> &lsquo;<samp>dc_luma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>dc_chroma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>freq_luma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>freq_chroma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>amp_luma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>amp_chroma</samp>&rsquo;</dt>
<dt> &lsquo;<samp>cbp</samp>&rsquo;</dt>
<dt> &lsquo;<samp>mv</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ring1</samp>&rsquo;</dt>
<dt> &lsquo;<samp>ring2</samp>&rsquo;</dt>
<dt> &lsquo;<samp>all</samp>&rsquo;</dt>
</dl>
<p>Default value is &quot;all&quot;, which will cycle through the list of all tests.
</p></dd>
</dl>
<p>For example the following:
</p><table><tr><td>&nbsp;</td><td><pre class="example">testsrc=t=dc_luma
</pre></td></tr></table>
<p>will generate a &quot;dc_luma&quot; test pattern.
</p>
<a name="frei0r_005fsrc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-frei0r_005fsrc">29.5 frei0r_src</a></h2>
<p>Provide a frei0r source.
</p>
<p>To enable compilation of this filter you need to install the frei0r
header and configure FFmpeg with <code>--enable-frei0r</code>.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>size</samp>&rsquo;</dt>
<dd><p>The size of the video to generate. For the syntax of this option, check the
&quot;Video size&quot; section in the ffmpeg-utils manual.
</p>
</dd>
<dt> &lsquo;<samp>framerate</samp>&rsquo;</dt>
<dd><p>Framerate of the generated video, may be a string of the form
<var>num</var>/<var>den</var> or a frame rate abbreviation.
</p>
</dd>
<dt> &lsquo;<samp>filter_name</samp>&rsquo;</dt>
<dd><p>The name to the frei0r source to load. For more information regarding frei0r and
how to set the parameters read the section <a href="#frei0r">frei0r</a> in the description of
the video filters.
</p>
</dd>
<dt> &lsquo;<samp>filter_params</samp>&rsquo;</dt>
<dd><p>A &rsquo;|&rsquo;-separated list of parameters to pass to the frei0r source.
</p>
</dd>
</dl>
<p>For example, to generate a frei0r partik0l source with size 200x200
and frame rate 10 which is overlayed on the overlay filter main input:
</p><table><tr><td>&nbsp;</td><td><pre class="example">frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
</pre></td></tr></table>
<a name="life"></a>
<h2 class="section"><a href="ffplay-all.html#toc-life">29.6 life</a></h2>
<p>Generate a life pattern.
</p>
<p>This source is based on a generalization of John Conway&rsquo;s life game.
</p>
<p>The sourced input represents a life grid, each pixel represents a cell
which can be in one of two possible states, alive or dead. Every cell
interacts with its eight neighbours, which are the cells that are
horizontally, vertically, or diagonally adjacent.
</p>
<p>At each interaction the grid evolves according to the adopted rule,
which specifies the number of neighbor alive cells which will make a
cell stay alive or born. The &lsquo;<samp>rule</samp>&rsquo; option allows one to specify
the rule to adopt.
</p>
<p>This source accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filename, f</samp>&rsquo;</dt>
<dd><p>Set the file from which to read the initial grid state. In the file,
each non-whitespace character is considered an alive cell, and newline
is used to delimit the end of each row.
</p>
<p>If this option is not specified, the initial grid is generated
randomly.
</p>
</dd>
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Set the video rate, that is the number of frames generated per second.
Default is 25.
</p>
</dd>
<dt> &lsquo;<samp>random_fill_ratio, ratio</samp>&rsquo;</dt>
<dd><p>Set the random fill ratio for the initial random grid. It is a
floating point number value ranging from 0 to 1, defaults to 1/PHI.
It is ignored when a file is specified.
</p>
</dd>
<dt> &lsquo;<samp>random_seed, seed</samp>&rsquo;</dt>
<dd><p>Set the seed for filling the initial random grid, must be an integer
included between 0 and UINT32_MAX. If not specified, or if explicitly
set to -1, the filter will try to use a good random seed on a best
effort basis.
</p>
</dd>
<dt> &lsquo;<samp>rule</samp>&rsquo;</dt>
<dd><p>Set the life rule.
</p>
<p>A rule can be specified with a code of the kind &quot;S<var>NS</var>/B<var>NB</var>&quot;,
where <var>NS</var> and <var>NB</var> are sequences of numbers in the range 0-8,
<var>NS</var> specifies the number of alive neighbor cells which make a
live cell stay alive, and <var>NB</var> the number of alive neighbor cells
which make a dead cell to become alive (i.e. to &quot;born&quot;).
&quot;s&quot; and &quot;b&quot; can be used in place of &quot;S&quot; and &quot;B&quot;, respectively.
</p>
<p>Alternatively a rule can be specified by an 18-bits integer. The 9
high order bits are used to encode the next cell state if it is alive
for each number of neighbor alive cells, the low order bits specify
the rule for &quot;borning&quot; new cells. Higher order bits encode for an
higher number of neighbor cells.
For example the number 6153 = <code>(12&lt;&lt;9)+9</code> specifies a stay alive
rule of 12 and a born rule of 9, which corresponds to &quot;S23/B03&quot;.
</p>
<p>Default value is &quot;S23/B3&quot;, which is the original Conway&rsquo;s game of life
rule, and will keep a cell alive if it has 2 or 3 neighbor alive
cells, and will born a new cell if there are three alive cells around
a dead cell.
</p>
</dd>
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Set the size of the output video. For the syntax of this option, check the
&quot;Video size&quot; section in the ffmpeg-utils manual.
</p>
<p>If &lsquo;<samp>filename</samp>&rsquo; is specified, the size is set by default to the
same size of the input file. If &lsquo;<samp>size</samp>&rsquo; is set, it must contain
the size specified in the input file, and the initial grid defined in
that file is centered in the larger resulting area.
</p>
<p>If a filename is not specified, the size value defaults to &quot;320x240&quot;
(used for a randomly generated initial grid).
</p>
</dd>
<dt> &lsquo;<samp>stitch</samp>&rsquo;</dt>
<dd><p>If set to 1, stitch the left and right grid edges together, and the
top and bottom edges also. Defaults to 1.
</p>
</dd>
<dt> &lsquo;<samp>mold</samp>&rsquo;</dt>
<dd><p>Set cell mold speed. If set, a dead cell will go from &lsquo;<samp>death_color</samp>&rsquo; to
&lsquo;<samp>mold_color</samp>&rsquo; with a step of &lsquo;<samp>mold</samp>&rsquo;. &lsquo;<samp>mold</samp>&rsquo; can have a
value from 0 to 255.
</p>
</dd>
<dt> &lsquo;<samp>life_color</samp>&rsquo;</dt>
<dd><p>Set the color of living (or new born) cells.
</p>
</dd>
<dt> &lsquo;<samp>death_color</samp>&rsquo;</dt>
<dd><p>Set the color of dead cells. If &lsquo;<samp>mold</samp>&rsquo; is set, this is the first color
used to represent a dead cell.
</p>
</dd>
<dt> &lsquo;<samp>mold_color</samp>&rsquo;</dt>
<dd><p>Set mold color, for definitely dead and moldy cells.
</p>
<p>For the syntax of these 3 color options, check the &quot;Color&quot; section in the
ffmpeg-utils manual.
</p></dd>
</dl>
<a name="Examples-50"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-50">29.6.1 Examples</a></h3>
<ul>
<li>
Read a grid from &lsquo;<tt>pattern</tt>&rsquo;, and center it on a grid of size
300x300 pixels:
<table><tr><td>&nbsp;</td><td><pre class="example">life=f=pattern:s=300x300
</pre></td></tr></table>
</li><li>
Generate a random grid of size 200x200, with a fill ratio of 2/3:
<table><tr><td>&nbsp;</td><td><pre class="example">life=ratio=2/3:s=200x200
</pre></td></tr></table>
</li><li>
Specify a custom rule for evolving a randomly generated grid:
<table><tr><td>&nbsp;</td><td><pre class="example">life=rule=S14/B34
</pre></td></tr></table>
</li><li>
Full example with slow death effect (mold) using <code>ffplay</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
</pre></td></tr></table>
</li></ul>
<p><a name="color"></a>
<a name="haldclutsrc"></a>
<a name="nullsrc"></a>
<a name="rgbtestsrc"></a>
<a name="smptebars"></a>
<a name="smptehdbars"></a>
<a name="testsrc"></a>
</p><a name="color_002c-haldclutsrc_002c-nullsrc_002c-rgbtestsrc_002c-smptebars_002c-smptehdbars_002c-testsrc"></a>
<h2 class="section"><a href="ffplay-all.html#toc-color_002c-haldclutsrc_002c-nullsrc_002c-rgbtestsrc_002c-smptebars_002c-smptehdbars_002c-testsrc">29.7 color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc</a></h2>
<p>The <code>color</code> source provides an uniformly colored input.
</p>
<p>The <code>haldclutsrc</code> source provides an identity Hald CLUT. See also
<a href="#haldclut">haldclut</a> filter.
</p>
<p>The <code>nullsrc</code> source returns unprocessed video frames. It is
mainly useful to be employed in analysis / debugging tools, or as the
source for filters which ignore the input data.
</p>
<p>The <code>rgbtestsrc</code> source generates an RGB test pattern useful for
detecting RGB vs BGR issues. You should see a red, green and blue
stripe from top to bottom.
</p>
<p>The <code>smptebars</code> source generates a color bars pattern, based on
the SMPTE Engineering Guideline EG 1-1990.
</p>
<p>The <code>smptehdbars</code> source generates a color bars pattern, based on
the SMPTE RP 219-2002.
</p>
<p>The <code>testsrc</code> source generates a test video pattern, showing a
color pattern, a scrolling gradient and a timestamp. This is mainly
intended for testing purposes.
</p>
<p>The sources accept the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>color, c</samp>&rsquo;</dt>
<dd><p>Specify the color of the source, only available in the <code>color</code>
source. For the syntax of this option, check the &quot;Color&quot; section in the
ffmpeg-utils manual.
</p>
</dd>
<dt> &lsquo;<samp>level</samp>&rsquo;</dt>
<dd><p>Specify the level of the Hald CLUT, only available in the <code>haldclutsrc</code>
source. A level of <code>N</code> generates a picture of <code>N*N*N</code> by <code>N*N*N</code>
pixels to be used as identity matrix for 3D lookup tables. Each component is
coded on a <code>1/(N*N)</code> scale.
</p>
</dd>
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Specify the size of the sourced video. For the syntax of this option, check the
&quot;Video size&quot; section in the ffmpeg-utils manual. The default value is
&quot;320x240&quot;.
</p>
<p>This option is not available with the <code>haldclutsrc</code> filter.
</p>
</dd>
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Specify the frame rate of the sourced video, as the number of frames
generated per second. It has to be a string in the format
<var>frame_rate_num</var>/<var>frame_rate_den</var>, an integer number, a float
number or a valid video frame rate abbreviation. The default value is
&quot;25&quot;.
</p>
</dd>
<dt> &lsquo;<samp>sar</samp>&rsquo;</dt>
<dd><p>Set the sample aspect ratio of the sourced video.
</p>
</dd>
<dt> &lsquo;<samp>duration, d</samp>&rsquo;</dt>
<dd><p>Set the video duration of the sourced video. The accepted syntax is:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[-]HH[:MM[:SS[.m...]]]
[-]S+[.m...]
</pre></td></tr></table>
<p>See also the function <code>av_parse_time()</code>.
</p>
<p>If not specified, or the expressed duration is negative, the video is
supposed to be generated forever.
</p>
</dd>
<dt> &lsquo;<samp>decimals, n</samp>&rsquo;</dt>
<dd><p>Set the number of decimals to show in the timestamp, only available in the
<code>testsrc</code> source.
</p>
<p>The displayed timestamp value will correspond to the original
timestamp value multiplied by the power of 10 of the specified
value. Default value is 0.
</p></dd>
</dl>
<p>For example the following:
</p><table><tr><td>&nbsp;</td><td><pre class="example">testsrc=duration=5.3:size=qcif:rate=10
</pre></td></tr></table>
<p>will generate a video with a duration of 5.3 seconds, with size
176x144 and a frame rate of 10 frames per second.
</p>
<p>The following graph description will generate a red source
with an opacity of 0.2, with size &quot;qcif&quot; and a frame rate of 10
frames per second.
</p><table><tr><td>&nbsp;</td><td><pre class="example">color=c=red@0.2:s=qcif:r=10
</pre></td></tr></table>
<p>If the input content is to be ignored, <code>nullsrc</code> can be used. The
following command generates noise in the luminance plane by employing
the <code>geq</code> filter:
</p><table><tr><td>&nbsp;</td><td><pre class="example">nullsrc=s=256x256, geq=random(1)*255:128:128
</pre></td></tr></table>
<a name="Commands-3"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands-3">29.7.1 Commands</a></h3>
<p>The <code>color</code> source supports the following commands:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>c, color</samp>&rsquo;</dt>
<dd><p>Set the color of the created image. Accepts the same syntax of the
corresponding &lsquo;<samp>color</samp>&rsquo; option.
</p></dd>
</dl>
<a name="Video-Sinks"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Video-Sinks">30. Video Sinks</a></h1>
<p>Below is a description of the currently available video sinks.
</p>
<a name="buffersink"></a>
<h2 class="section"><a href="ffplay-all.html#toc-buffersink">30.1 buffersink</a></h2>
<p>Buffer video frames, and make them available to the end of the filter
graph.
</p>
<p>This sink is mainly intended for a programmatic use, in particular
through the interface defined in &lsquo;<tt>libavfilter/buffersink.h</tt>&rsquo;
or the options system.
</p>
<p>It accepts a pointer to an AVBufferSinkContext structure, which
defines the incoming buffers&rsquo; formats, to be passed as the opaque
parameter to <code>avfilter_init_filter</code> for initialization.
</p>
<a name="nullsink"></a>
<h2 class="section"><a href="ffplay-all.html#toc-nullsink">30.2 nullsink</a></h2>
<p>Null video sink, do absolutely nothing with the input video. It is
mainly useful as a template and to be employed in analysis / debugging
tools.
</p>
<a name="Multimedia-Filters"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Multimedia-Filters">31. Multimedia Filters</a></h1>
<p>Below is a description of the currently available multimedia filters.
</p>
<a name="avectorscope"></a>
<h2 class="section"><a href="ffplay-all.html#toc-avectorscope">31.1 avectorscope</a></h2>
<p>Convert input audio to a video output, representing the audio vector
scope.
</p>
<p>The filter is used to measure the difference between channels of stereo
audio stream. A monoaural signal, consisting of identical left and right
signal, results in straight vertical line. Any stereo separation is visible
as a deviation from this line, creating a Lissajous figure.
If the straight (or deviation from it) but horizontal line appears this
indicates that the left and right channels are out of phase.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode, m</samp>&rsquo;</dt>
<dd><p>Set the vectorscope mode.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>lissajous</samp>&rsquo;</dt>
<dd><p>Lissajous rotated by 45 degrees.
</p>
</dd>
<dt> &lsquo;<samp>lissajous_xy</samp>&rsquo;</dt>
<dd><p>Same as above but not rotated.
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>lissajous</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Set the video size for the output. For the syntax of this option, check the &quot;Video size&quot;
section in the ffmpeg-utils manual. Default value is <code>400x400</code>.
</p>
</dd>
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Set the output frame rate. Default value is <code>25</code>.
</p>
</dd>
<dt> &lsquo;<samp>rc</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gc</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bc</samp>&rsquo;</dt>
<dd><p>Specify the red, green and blue contrast. Default values are <code>40</code>, <code>160</code> and <code>80</code>.
Allowed range is <code>[0, 255]</code>.
</p>
</dd>
<dt> &lsquo;<samp>rf</samp>&rsquo;</dt>
<dt> &lsquo;<samp>gf</samp>&rsquo;</dt>
<dt> &lsquo;<samp>bf</samp>&rsquo;</dt>
<dd><p>Specify the red, green and blue fade. Default values are <code>15</code>, <code>10</code> and <code>5</code>.
Allowed range is <code>[0, 255]</code>.
</p>
</dd>
<dt> &lsquo;<samp>zoom</samp>&rsquo;</dt>
<dd><p>Set the zoom factor. Default value is <code>1</code>. Allowed range is <code>[1, 10]</code>.
</p></dd>
</dl>
<a name="Examples-73"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-73">31.1.1 Examples</a></h3>
<ul>
<li>
Complete example using <code>ffplay</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
[a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
</pre></td></tr></table>
</li></ul>
<a name="concat-3"></a>
<h2 class="section"><a href="ffplay-all.html#toc-concat-3">31.2 concat</a></h2>
<p>Concatenate audio and video streams, joining them together one after the
other.
</p>
<p>The filter works on segments of synchronized video and audio streams. All
segments must have the same number of streams of each type, and that will
also be the number of streams at output.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>Set the number of segments. Default is 2.
</p>
</dd>
<dt> &lsquo;<samp>v</samp>&rsquo;</dt>
<dd><p>Set the number of output video streams, that is also the number of video
streams in each segment. Default is 1.
</p>
</dd>
<dt> &lsquo;<samp>a</samp>&rsquo;</dt>
<dd><p>Set the number of output audio streams, that is also the number of video
streams in each segment. Default is 0.
</p>
</dd>
<dt> &lsquo;<samp>unsafe</samp>&rsquo;</dt>
<dd><p>Activate unsafe mode: do not fail if segments have a different format.
</p>
</dd>
</dl>
<p>The filter has <var>v</var>+<var>a</var> outputs: first <var>v</var> video outputs, then
<var>a</var> audio outputs.
</p>
<p>There are <var>n</var>x(<var>v</var>+<var>a</var>) inputs: first the inputs for the first
segment, in the same order as the outputs, then the inputs for the second
segment, etc.
</p>
<p>Related streams do not always have exactly the same duration, for various
reasons including codec frame size or sloppy authoring. For that reason,
related synchronized streams (e.g. a video and its audio track) should be
concatenated at once. The concat filter will use the duration of the longest
stream in each segment (except the last one), and if necessary pad shorter
audio streams with silence.
</p>
<p>For this filter to work correctly, all segments must start at timestamp 0.
</p>
<p>All corresponding streams must have the same parameters in all segments; the
filtering system will automatically select a common pixel format for video
streams, and a common sample format, sample rate and channel layout for
audio streams, but other settings, such as resolution, must be converted
explicitly by the user.
</p>
<p>Different frame rates are acceptable but will result in variable frame rate
at output; be sure to configure the output file to handle it.
</p>
<a name="Examples-53"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-53">31.2.1 Examples</a></h3>
<ul>
<li>
Concatenate an opening, an episode and an ending, all in bilingual version
(video in stream 0, audio in streams 1 and 2):
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
'[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
concat=n=3:v=1:a=2 [v] [a1] [a2]' \
-map '[v]' -map '[a1]' -map '[a2]' output.mkv
</pre></td></tr></table>
</li><li>
Concatenate two parts, handling audio and video separately, using the
(a)movie sources, and adjusting the resolution:
<table><tr><td>&nbsp;</td><td><pre class="example">movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
</pre></td></tr></table>
<p>Note that a desync will happen at the stitch if the audio and video streams
do not have exactly the same duration in the first file.
</p>
</li></ul>
<a name="ebur128"></a>
<h2 class="section"><a href="ffplay-all.html#toc-ebur128">31.3 ebur128</a></h2>
<p>EBU R128 scanner filter. This filter takes an audio stream as input and outputs
it unchanged. By default, it logs a message at a frequency of 10Hz with the
Momentary loudness (identified by <code>M</code>), Short-term loudness (<code>S</code>),
Integrated loudness (<code>I</code>) and Loudness Range (<code>LRA</code>).
</p>
<p>The filter also has a video output (see the <var>video</var> option) with a real
time graph to observe the loudness evolution. The graphic contains the logged
message mentioned above, so it is not printed anymore when this option is set,
unless the verbose logging is set. The main graphing area contains the
short-term loudness (3 seconds of analysis), and the gauge on the right is for
the momentary loudness (400 milliseconds).
</p>
<p>More information about the Loudness Recommendation EBU R128 on
<a href="http://tech.ebu.ch/loudness">http://tech.ebu.ch/loudness</a>.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>video</samp>&rsquo;</dt>
<dd><p>Activate the video output. The audio stream is passed unchanged whether this
option is set or no. The video stream will be the first output stream if
activated. Default is <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>size</samp>&rsquo;</dt>
<dd><p>Set the video size. This option is for video only. For the syntax of this
option, check the &quot;Video size&quot; section in the ffmpeg-utils manual. Default
and minimum resolution is <code>640x480</code>.
</p>
</dd>
<dt> &lsquo;<samp>meter</samp>&rsquo;</dt>
<dd><p>Set the EBU scale meter. Default is <code>9</code>. Common values are <code>9</code> and
<code>18</code>, respectively for EBU scale meter +9 and EBU scale meter +18. Any
other integer value between this range is allowed.
</p>
</dd>
<dt> &lsquo;<samp>metadata</samp>&rsquo;</dt>
<dd><p>Set metadata injection. If set to <code>1</code>, the audio input will be segmented
into 100ms output frames, each of them containing various loudness information
in metadata. All the metadata keys are prefixed with <code>lavfi.r128.</code>.
</p>
<p>Default is <code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>framelog</samp>&rsquo;</dt>
<dd><p>Force the frame logging level.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>info</samp>&rsquo;</dt>
<dd><p>information logging level
</p></dd>
<dt> &lsquo;<samp>verbose</samp>&rsquo;</dt>
<dd><p>verbose logging level
</p></dd>
</dl>
<p>By default, the logging level is set to <var>info</var>. If the &lsquo;<samp>video</samp>&rsquo; or
the &lsquo;<samp>metadata</samp>&rsquo; options are set, it switches to <var>verbose</var>.
</p>
</dd>
<dt> &lsquo;<samp>peak</samp>&rsquo;</dt>
<dd><p>Set peak mode(s).
</p>
<p>Available modes can be cumulated (the option is a <code>flag</code> type). Possible
values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>Disable any peak mode (default).
</p></dd>
<dt> &lsquo;<samp>sample</samp>&rsquo;</dt>
<dd><p>Enable sample-peak mode.
</p>
<p>Simple peak mode looking for the higher sample value. It logs a message
for sample-peak (identified by <code>SPK</code>).
</p></dd>
<dt> &lsquo;<samp>true</samp>&rsquo;</dt>
<dd><p>Enable true-peak mode.
</p>
<p>If enabled, the peak lookup is done on an over-sampled version of the input
stream for better peak accuracy. It logs a message for true-peak.
(identified by <code>TPK</code>) and true-peak per frame (identified by <code>FTPK</code>).
This mode requires a build with <code>libswresample</code>.
</p></dd>
</dl>
</dd>
</dl>
<a name="Examples-70"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-70">31.3.1 Examples</a></h3>
<ul>
<li>
Real-time graph using <code>ffplay</code>, with a EBU scale meter +18:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi -i &quot;amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]&quot;
</pre></td></tr></table>
</li><li>
Run an analysis with <code>ffmpeg</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
</pre></td></tr></table>
</li></ul>
<a name="interleave_002c-ainterleave"></a>
<h2 class="section"><a href="ffplay-all.html#toc-interleave_002c-ainterleave">31.4 interleave, ainterleave</a></h2>
<p>Temporally interleave frames from several inputs.
</p>
<p><code>interleave</code> works with video inputs, <code>ainterleave</code> with audio.
</p>
<p>These filters read frames from several inputs and send the oldest
queued frame to the output.
</p>
<p>Input streams must have a well defined, monotonically increasing frame
timestamp values.
</p>
<p>In order to submit one frame to output, these filters need to enqueue
at least one frame for each input, so they cannot work in case one
input is not yet terminated and will not receive incoming frames.
</p>
<p>For example consider the case when one input is a <code>select</code> filter
which always drop input frames. The <code>interleave</code> filter will keep
reading from that input, but it will never be able to send new frames
to output until the input will send an end-of-stream signal.
</p>
<p>Also, depending on inputs synchronization, the filters will drop
frames in case one input receives more frames than the other ones, and
the queue is already filled.
</p>
<p>These filters accept the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>nb_inputs, n</samp>&rsquo;</dt>
<dd><p>Set the number of different inputs, it is 2 by default.
</p></dd>
</dl>
<a name="Examples-2"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-2">31.4.1 Examples</a></h3>
<ul>
<li>
Interleave frames belonging to different streams using <code>ffmpeg</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex &quot;[0:v][1:v] interleave&quot; out.avi
</pre></td></tr></table>
</li><li>
Add flickering blur effect:
<table><tr><td>&nbsp;</td><td><pre class="example">select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
</pre></td></tr></table>
</li></ul>
<a name="perms_002c-aperms"></a>
<h2 class="section"><a href="ffplay-all.html#toc-perms_002c-aperms">31.5 perms, aperms</a></h2>
<p>Set read/write permissions for the output frames.
</p>
<p>These filters are mainly aimed at developers to test direct path in the
following filter in the filtergraph.
</p>
<p>The filters accept the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Select the permissions mode.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>Do nothing. This is the default.
</p></dd>
<dt> &lsquo;<samp>ro</samp>&rsquo;</dt>
<dd><p>Set all the output frames read-only.
</p></dd>
<dt> &lsquo;<samp>rw</samp>&rsquo;</dt>
<dd><p>Set all the output frames directly writable.
</p></dd>
<dt> &lsquo;<samp>toggle</samp>&rsquo;</dt>
<dd><p>Make the frame read-only if writable, and writable if read-only.
</p></dd>
<dt> &lsquo;<samp>random</samp>&rsquo;</dt>
<dd><p>Set each output frame read-only or writable randomly.
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>seed</samp>&rsquo;</dt>
<dd><p>Set the seed for the <var>random</var> mode, must be an integer included between
<code>0</code> and <code>UINT32_MAX</code>. If not specified, or if explicitly set to
<code>-1</code>, the filter will try to use a good random seed on a best effort
basis.
</p></dd>
</dl>
<p>Note: in case of auto-inserted filter between the permission filter and the
following one, the permission might not be received as expected in that
following filter. Inserting a <a href="#format">format</a> or <a href="#aformat">aformat</a> filter before the
perms/aperms filter can avoid this problem.
</p>
<a name="select_002c-aselect"></a>
<h2 class="section"><a href="ffplay-all.html#toc-select_002c-aselect">31.6 select, aselect</a></h2>
<p>Select frames to pass in output.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>expr, e</samp>&rsquo;</dt>
<dd><p>Set expression, which is evaluated for each input frame.
</p>
<p>If the expression is evaluated to zero, the frame is discarded.
</p>
<p>If the evaluation result is negative or NaN, the frame is sent to the
first output; otherwise it is sent to the output with index
<code>ceil(val)-1</code>, assuming that the input index starts from 0.
</p>
<p>For example a value of <code>1.2</code> corresponds to the output with index
<code>ceil(1.2)-1 = 2-1 = 1</code>, that is the second output.
</p>
</dd>
<dt> &lsquo;<samp>outputs, n</samp>&rsquo;</dt>
<dd><p>Set the number of outputs. The output to which to send the selected
frame is based on the result of the evaluation. Default value is 1.
</p></dd>
</dl>
<p>The expression can contain the following constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>the sequential number of the filtered frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>selected_n</samp>&rsquo;</dt>
<dd><p>the sequential number of the selected frame, starting from 0
</p>
</dd>
<dt> &lsquo;<samp>prev_selected_n</samp>&rsquo;</dt>
<dd><p>the sequential number of the last selected frame, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>TB</samp>&rsquo;</dt>
<dd><p>timebase of the input timestamps
</p>
</dd>
<dt> &lsquo;<samp>pts</samp>&rsquo;</dt>
<dd><p>the PTS (Presentation TimeStamp) of the filtered video frame,
expressed in <var>TB</var> units, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>the PTS (Presentation TimeStamp) of the filtered video frame,
expressed in seconds, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>prev_pts</samp>&rsquo;</dt>
<dd><p>the PTS of the previously filtered video frame, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>prev_selected_pts</samp>&rsquo;</dt>
<dd><p>the PTS of the last previously filtered video frame, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>prev_selected_t</samp>&rsquo;</dt>
<dd><p>the PTS of the last previously selected video frame, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>start_pts</samp>&rsquo;</dt>
<dd><p>the PTS of the first video frame in the video, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>start_t</samp>&rsquo;</dt>
<dd><p>the time of the first video frame in the video, NAN if undefined
</p>
</dd>
<dt> &lsquo;<samp>pict_type <em>(video only)</em></samp>&rsquo;</dt>
<dd><p>the type of the filtered frame, can assume one of the following
values:
</p><dl compact="compact">
<dt> &lsquo;<samp>I</samp>&rsquo;</dt>
<dt> &lsquo;<samp>P</samp>&rsquo;</dt>
<dt> &lsquo;<samp>B</samp>&rsquo;</dt>
<dt> &lsquo;<samp>S</samp>&rsquo;</dt>
<dt> &lsquo;<samp>SI</samp>&rsquo;</dt>
<dt> &lsquo;<samp>SP</samp>&rsquo;</dt>
<dt> &lsquo;<samp>BI</samp>&rsquo;</dt>
</dl>
</dd>
<dt> &lsquo;<samp>interlace_type <em>(video only)</em></samp>&rsquo;</dt>
<dd><p>the frame interlace type, can assume one of the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>PROGRESSIVE</samp>&rsquo;</dt>
<dd><p>the frame is progressive (not interlaced)
</p></dd>
<dt> &lsquo;<samp>TOPFIRST</samp>&rsquo;</dt>
<dd><p>the frame is top-field-first
</p></dd>
<dt> &lsquo;<samp>BOTTOMFIRST</samp>&rsquo;</dt>
<dd><p>the frame is bottom-field-first
</p></dd>
</dl>
</dd>
<dt> &lsquo;<samp>consumed_sample_n <em>(audio only)</em></samp>&rsquo;</dt>
<dd><p>the number of selected samples before the current frame
</p>
</dd>
<dt> &lsquo;<samp>samples_n <em>(audio only)</em></samp>&rsquo;</dt>
<dd><p>the number of samples in the current frame
</p>
</dd>
<dt> &lsquo;<samp>sample_rate <em>(audio only)</em></samp>&rsquo;</dt>
<dd><p>the input sample rate
</p>
</dd>
<dt> &lsquo;<samp>key</samp>&rsquo;</dt>
<dd><p>1 if the filtered frame is a key-frame, 0 otherwise
</p>
</dd>
<dt> &lsquo;<samp>pos</samp>&rsquo;</dt>
<dd><p>the position in the file of the filtered frame, -1 if the information
is not available (e.g. for synthetic video)
</p>
</dd>
<dt> &lsquo;<samp>scene <em>(video only)</em></samp>&rsquo;</dt>
<dd><p>value between 0 and 1 to indicate a new scene; a low value reflects a low
probability for the current frame to introduce a new scene, while a higher
value means the current frame is more likely to be one (see the example below)
</p>
</dd>
</dl>
<p>The default value of the select expression is &quot;1&quot;.
</p>
<a name="Examples-29"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-29">31.6.1 Examples</a></h3>
<ul>
<li>
Select all frames in input:
<table><tr><td>&nbsp;</td><td><pre class="example">select
</pre></td></tr></table>
<p>The example above is the same as:
</p><table><tr><td>&nbsp;</td><td><pre class="example">select=1
</pre></td></tr></table>
</li><li>
Skip all frames:
<table><tr><td>&nbsp;</td><td><pre class="example">select=0
</pre></td></tr></table>
</li><li>
Select only I-frames:
<table><tr><td>&nbsp;</td><td><pre class="example">select='eq(pict_type\,I)'
</pre></td></tr></table>
</li><li>
Select one frame every 100:
<table><tr><td>&nbsp;</td><td><pre class="example">select='not(mod(n\,100))'
</pre></td></tr></table>
</li><li>
Select only frames contained in the 10-20 time interval:
<table><tr><td>&nbsp;</td><td><pre class="example">select=between(t\,10\,20)
</pre></td></tr></table>
</li><li>
Select only I frames contained in the 10-20 time interval:
<table><tr><td>&nbsp;</td><td><pre class="example">select=between(t\,10\,20)*eq(pict_type\,I)
</pre></td></tr></table>
</li><li>
Select frames with a minimum distance of 10 seconds:
<table><tr><td>&nbsp;</td><td><pre class="example">select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
</pre></td></tr></table>
</li><li>
Use aselect to select only audio frames with samples number &gt; 100:
<table><tr><td>&nbsp;</td><td><pre class="example">aselect='gt(samples_n\,100)'
</pre></td></tr></table>
</li><li>
Create a mosaic of the first scenes:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
</pre></td></tr></table>
<p>Comparing <var>scene</var> against a value between 0.3 and 0.5 is generally a sane
choice.
</p>
</li><li>
Send even and odd frames to separate outputs, and compose them:
<table><tr><td>&nbsp;</td><td><pre class="example">select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
</pre></td></tr></table>
</li></ul>
<a name="sendcmd_002c-asendcmd"></a>
<h2 class="section"><a href="ffplay-all.html#toc-sendcmd_002c-asendcmd">31.7 sendcmd, asendcmd</a></h2>
<p>Send commands to filters in the filtergraph.
</p>
<p>These filters read commands to be sent to other filters in the
filtergraph.
</p>
<p><code>sendcmd</code> must be inserted between two video filters,
<code>asendcmd</code> must be inserted between two audio filters, but apart
from that they act the same way.
</p>
<p>The specification of commands can be provided in the filter arguments
with the <var>commands</var> option, or in a file specified by the
<var>filename</var> option.
</p>
<p>These filters accept the following options:
</p><dl compact="compact">
<dt> &lsquo;<samp>commands, c</samp>&rsquo;</dt>
<dd><p>Set the commands to be read and sent to the other filters.
</p></dd>
<dt> &lsquo;<samp>filename, f</samp>&rsquo;</dt>
<dd><p>Set the filename of the commands to be read and sent to the other
filters.
</p></dd>
</dl>
<a name="Commands-syntax"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Commands-syntax">31.7.1 Commands syntax</a></h3>
<p>A commands description consists of a sequence of interval
specifications, comprising a list of commands to be executed when a
particular event related to that interval occurs. The occurring event
is typically the current frame time entering or leaving a given time
interval.
</p>
<p>An interval is specified by the following syntax:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>START</var>[-<var>END</var>] <var>COMMANDS</var>;
</pre></td></tr></table>
<p>The time interval is specified by the <var>START</var> and <var>END</var> times.
<var>END</var> is optional and defaults to the maximum time.
</p>
<p>The current frame time is considered within the specified interval if
it is included in the interval [<var>START</var>, <var>END</var>), that is when
the time is greater or equal to <var>START</var> and is lesser than
<var>END</var>.
</p>
<p><var>COMMANDS</var> consists of a sequence of one or more command
specifications, separated by &quot;,&quot;, relating to that interval. The
syntax of a command specification is given by:
</p><table><tr><td>&nbsp;</td><td><pre class="example">[<var>FLAGS</var>] <var>TARGET</var> <var>COMMAND</var> <var>ARG</var>
</pre></td></tr></table>
<p><var>FLAGS</var> is optional and specifies the type of events relating to
the time interval which enable sending the specified command, and must
be a non-null sequence of identifier flags separated by &quot;+&quot; or &quot;|&quot; and
enclosed between &quot;[&quot; and &quot;]&quot;.
</p>
<p>The following flags are recognized:
</p><dl compact="compact">
<dt> &lsquo;<samp>enter</samp>&rsquo;</dt>
<dd><p>The command is sent when the current frame timestamp enters the
specified interval. In other words, the command is sent when the
previous frame timestamp was not in the given interval, and the
current is.
</p>
</dd>
<dt> &lsquo;<samp>leave</samp>&rsquo;</dt>
<dd><p>The command is sent when the current frame timestamp leaves the
specified interval. In other words, the command is sent when the
previous frame timestamp was in the given interval, and the
current is not.
</p></dd>
</dl>
<p>If <var>FLAGS</var> is not specified, a default value of <code>[enter]</code> is
assumed.
</p>
<p><var>TARGET</var> specifies the target of the command, usually the name of
the filter class or a specific filter instance name.
</p>
<p><var>COMMAND</var> specifies the name of the command for the target filter.
</p>
<p><var>ARG</var> is optional and specifies the optional list of argument for
the given <var>COMMAND</var>.
</p>
<p>Between one interval specification and another, whitespaces, or
sequences of characters starting with <code>#</code> until the end of line,
are ignored and can be used to annotate comments.
</p>
<p>A simplified BNF description of the commands specification syntax
follows:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>COMMAND_FLAG</var> ::= &quot;enter&quot; | &quot;leave&quot;
<var>COMMAND_FLAGS</var> ::= <var>COMMAND_FLAG</var> [(+|&quot;|&quot;)<var>COMMAND_FLAG</var>]
<var>COMMAND</var> ::= [&quot;[&quot; <var>COMMAND_FLAGS</var> &quot;]&quot;] <var>TARGET</var> <var>COMMAND</var> [<var>ARG</var>]
<var>COMMANDS</var> ::= <var>COMMAND</var> [,<var>COMMANDS</var>]
<var>INTERVAL</var> ::= <var>START</var>[-<var>END</var>] <var>COMMANDS</var>
<var>INTERVALS</var> ::= <var>INTERVAL</var>[;<var>INTERVALS</var>]
</pre></td></tr></table>
<a name="Examples-47"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-47">31.7.2 Examples</a></h3>
<ul>
<li>
Specify audio tempo change at second 4:
<table><tr><td>&nbsp;</td><td><pre class="example">asendcmd=c='4.0 atempo tempo 1.5',atempo
</pre></td></tr></table>
</li><li>
Specify a list of drawtext and hue commands in a file.
<table><tr><td>&nbsp;</td><td><pre class="example"># show text in the interval 5-10
5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
[leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
# desaturate the image in the interval 15-20
15.0-20.0 [enter] hue s 0,
[enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
[leave] hue s 1,
[leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
# apply an exponential saturation fade-out effect, starting from time 25
25 [enter] hue s exp(25-t)
</pre></td></tr></table>
<p>A filtergraph allowing to read and process the above command list
stored in a file &lsquo;<tt>test.cmd</tt>&rsquo;, can be specified with:
</p><table><tr><td>&nbsp;</td><td><pre class="example">sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
</pre></td></tr></table>
</li></ul>
<p><a name="setpts"></a>
</p><a name="setpts_002c-asetpts"></a>
<h2 class="section"><a href="ffplay-all.html#toc-setpts_002c-asetpts">31.8 setpts, asetpts</a></h2>
<p>Change the PTS (presentation timestamp) of the input frames.
</p>
<p><code>setpts</code> works on video frames, <code>asetpts</code> on audio frames.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>expr</samp>&rsquo;</dt>
<dd><p>The expression which is evaluated for each frame to construct its timestamp.
</p>
</dd>
</dl>
<p>The expression is evaluated through the eval API and can contain the following
constants:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>FRAME_RATE</samp>&rsquo;</dt>
<dd><p>frame rate, only defined for constant frame-rate video
</p>
</dd>
<dt> &lsquo;<samp>PTS</samp>&rsquo;</dt>
<dd><p>the presentation timestamp in input
</p>
</dd>
<dt> &lsquo;<samp>N</samp>&rsquo;</dt>
<dd><p>the count of the input frame for video or the number of consumed samples,
not including the current frame for audio, starting from 0.
</p>
</dd>
<dt> &lsquo;<samp>NB_CONSUMED_SAMPLES</samp>&rsquo;</dt>
<dd><p>the number of consumed samples, not including the current frame (only
audio)
</p>
</dd>
<dt> &lsquo;<samp>NB_SAMPLES, S</samp>&rsquo;</dt>
<dd><p>the number of samples in the current frame (only audio)
</p>
</dd>
<dt> &lsquo;<samp>SAMPLE_RATE, SR</samp>&rsquo;</dt>
<dd><p>audio sample rate
</p>
</dd>
<dt> &lsquo;<samp>STARTPTS</samp>&rsquo;</dt>
<dd><p>the PTS of the first frame
</p>
</dd>
<dt> &lsquo;<samp>STARTT</samp>&rsquo;</dt>
<dd><p>the time in seconds of the first frame
</p>
</dd>
<dt> &lsquo;<samp>INTERLACED</samp>&rsquo;</dt>
<dd><p>tell if the current frame is interlaced
</p>
</dd>
<dt> &lsquo;<samp>T</samp>&rsquo;</dt>
<dd><p>the time in seconds of the current frame
</p>
</dd>
<dt> &lsquo;<samp>POS</samp>&rsquo;</dt>
<dd><p>original position in the file of the frame, or undefined if undefined
for the current frame
</p>
</dd>
<dt> &lsquo;<samp>PREV_INPTS</samp>&rsquo;</dt>
<dd><p>previous input PTS
</p>
</dd>
<dt> &lsquo;<samp>PREV_INT</samp>&rsquo;</dt>
<dd><p>previous input time in seconds
</p>
</dd>
<dt> &lsquo;<samp>PREV_OUTPTS</samp>&rsquo;</dt>
<dd><p>previous output PTS
</p>
</dd>
<dt> &lsquo;<samp>PREV_OUTT</samp>&rsquo;</dt>
<dd><p>previous output time in seconds
</p>
</dd>
<dt> &lsquo;<samp>RTCTIME</samp>&rsquo;</dt>
<dd><p>wallclock (RTC) time in microseconds. This is deprecated, use time(0)
instead.
</p>
</dd>
<dt> &lsquo;<samp>RTCSTART</samp>&rsquo;</dt>
<dd><p>wallclock (RTC) time at the start of the movie in microseconds
</p>
</dd>
<dt> &lsquo;<samp>TB</samp>&rsquo;</dt>
<dd><p>timebase of the input timestamps
</p>
</dd>
</dl>
<a name="Examples-16"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-16">31.8.1 Examples</a></h3>
<ul>
<li>
Start counting PTS from zero
<table><tr><td>&nbsp;</td><td><pre class="example">setpts=PTS-STARTPTS
</pre></td></tr></table>
</li><li>
Apply fast motion effect:
<table><tr><td>&nbsp;</td><td><pre class="example">setpts=0.5*PTS
</pre></td></tr></table>
</li><li>
Apply slow motion effect:
<table><tr><td>&nbsp;</td><td><pre class="example">setpts=2.0*PTS
</pre></td></tr></table>
</li><li>
Set fixed rate of 25 frames per second:
<table><tr><td>&nbsp;</td><td><pre class="example">setpts=N/(25*TB)
</pre></td></tr></table>
</li><li>
Set fixed rate 25 fps with some jitter:
<table><tr><td>&nbsp;</td><td><pre class="example">setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
</pre></td></tr></table>
</li><li>
Apply an offset of 10 seconds to the input PTS:
<table><tr><td>&nbsp;</td><td><pre class="example">setpts=PTS+10/TB
</pre></td></tr></table>
</li><li>
Generate timestamps from a &quot;live source&quot; and rebase onto the current timebase:
<table><tr><td>&nbsp;</td><td><pre class="example">setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
</pre></td></tr></table>
</li><li>
Generate timestamps by counting samples:
<table><tr><td>&nbsp;</td><td><pre class="example">asetpts=N/SR/TB
</pre></td></tr></table>
</li></ul>
<a name="settb_002c-asettb"></a>
<h2 class="section"><a href="ffplay-all.html#toc-settb_002c-asettb">31.9 settb, asettb</a></h2>
<p>Set the timebase to use for the output frames timestamps.
It is mainly useful for testing timebase configuration.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>expr, tb</samp>&rsquo;</dt>
<dd><p>The expression which is evaluated into the output timebase.
</p>
</dd>
</dl>
<p>The value for &lsquo;<samp>tb</samp>&rsquo; is an arithmetic expression representing a
rational. The expression can contain the constants &quot;AVTB&quot; (the default
timebase), &quot;intb&quot; (the input timebase) and &quot;sr&quot; (the sample rate,
audio only). Default value is &quot;intb&quot;.
</p>
<a name="Examples-8"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-8">31.9.1 Examples</a></h3>
<ul>
<li>
Set the timebase to 1/25:
<table><tr><td>&nbsp;</td><td><pre class="example">settb=expr=1/25
</pre></td></tr></table>
</li><li>
Set the timebase to 1/10:
<table><tr><td>&nbsp;</td><td><pre class="example">settb=expr=0.1
</pre></td></tr></table>
</li><li>
Set the timebase to 1001/1000:
<table><tr><td>&nbsp;</td><td><pre class="example">settb=1+0.001
</pre></td></tr></table>
</li><li>
Set the timebase to 2*intb:
<table><tr><td>&nbsp;</td><td><pre class="example">settb=2*intb
</pre></td></tr></table>
</li><li>
Set the default timebase value:
<table><tr><td>&nbsp;</td><td><pre class="example">settb=AVTB
</pre></td></tr></table>
</li></ul>
<a name="showspectrum"></a>
<h2 class="section"><a href="ffplay-all.html#toc-showspectrum">31.10 showspectrum</a></h2>
<p>Convert input audio to a video output, representing the audio frequency
spectrum.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Specify the video size for the output. For the syntax of this option, check
the &quot;Video size&quot; section in the ffmpeg-utils manual. Default value is
<code>640x512</code>.
</p>
</dd>
<dt> &lsquo;<samp>slide</samp>&rsquo;</dt>
<dd><p>Specify if the spectrum should slide along the window. Default value is
<code>0</code>.
</p>
</dd>
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Specify display mode.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>combined</samp>&rsquo;</dt>
<dd><p>all channels are displayed in the same row
</p></dd>
<dt> &lsquo;<samp>separate</samp>&rsquo;</dt>
<dd><p>all channels are displayed in separate rows
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>combined</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>color</samp>&rsquo;</dt>
<dd><p>Specify display color mode.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>channel</samp>&rsquo;</dt>
<dd><p>each channel is displayed in a separate color
</p></dd>
<dt> &lsquo;<samp>intensity</samp>&rsquo;</dt>
<dd><p>each channel is is displayed using the same color scheme
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>channel</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>scale</samp>&rsquo;</dt>
<dd><p>Specify scale used for calculating intensity color values.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>lin</samp>&rsquo;</dt>
<dd><p>linear
</p></dd>
<dt> &lsquo;<samp>sqrt</samp>&rsquo;</dt>
<dd><p>square root, default
</p></dd>
<dt> &lsquo;<samp>cbrt</samp>&rsquo;</dt>
<dd><p>cubic root
</p></dd>
<dt> &lsquo;<samp>log</samp>&rsquo;</dt>
<dd><p>logarithmic
</p></dd>
</dl>
<p>Default value is &lsquo;<samp>sqrt</samp>&rsquo;.
</p>
</dd>
<dt> &lsquo;<samp>saturation</samp>&rsquo;</dt>
<dd><p>Set saturation modifier for displayed colors. Negative values provide
alternative color scheme. <code>0</code> is no saturation at all.
Saturation must be in [-10.0, 10.0] range.
Default value is <code>1</code>.
</p>
</dd>
<dt> &lsquo;<samp>win_func</samp>&rsquo;</dt>
<dd><p>Set window function.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt> &lsquo;<samp>none</samp>&rsquo;</dt>
<dd><p>No samples pre-processing (do not expect this to be faster)
</p></dd>
<dt> &lsquo;<samp>hann</samp>&rsquo;</dt>
<dd><p>Hann window
</p></dd>
<dt> &lsquo;<samp>hamming</samp>&rsquo;</dt>
<dd><p>Hamming window
</p></dd>
<dt> &lsquo;<samp>blackman</samp>&rsquo;</dt>
<dd><p>Blackman window
</p></dd>
</dl>
<p>Default value is <code>hann</code>.
</p></dd>
</dl>
<p>The usage is very similar to the showwaves filter; see the examples in that
section.
</p>
<a name="Examples-74"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-74">31.10.1 Examples</a></h3>
<ul>
<li>
Large window with logarithmic color scaling:
<table><tr><td>&nbsp;</td><td><pre class="example">showspectrum=s=1280x480:scale=log
</pre></td></tr></table>
</li><li>
Complete example for a colored and sliding spectrum per channel using <code>ffplay</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
[a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
</pre></td></tr></table>
</li></ul>
<a name="showwaves"></a>
<h2 class="section"><a href="ffplay-all.html#toc-showwaves">31.11 showwaves</a></h2>
<p>Convert input audio to a video output, representing the samples waves.
</p>
<p>The filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>size, s</samp>&rsquo;</dt>
<dd><p>Specify the video size for the output. For the syntax of this option, check
the &quot;Video size&quot; section in the ffmpeg-utils manual. Default value
is &quot;600x240&quot;.
</p>
</dd>
<dt> &lsquo;<samp>mode</samp>&rsquo;</dt>
<dd><p>Set display mode.
</p>
<p>Available values are:
</p><dl compact="compact">
<dt> &lsquo;<samp>point</samp>&rsquo;</dt>
<dd><p>Draw a point for each sample.
</p>
</dd>
<dt> &lsquo;<samp>line</samp>&rsquo;</dt>
<dd><p>Draw a vertical line for each sample.
</p></dd>
</dl>
<p>Default value is <code>point</code>.
</p>
</dd>
<dt> &lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>Set the number of samples which are printed on the same column. A
larger value will decrease the frame rate. Must be a positive
integer. This option can be set only if the value for <var>rate</var>
is not explicitly specified.
</p>
</dd>
<dt> &lsquo;<samp>rate, r</samp>&rsquo;</dt>
<dd><p>Set the (approximate) output frame rate. This is done by setting the
option <var>n</var>. Default value is &quot;25&quot;.
</p>
</dd>
</dl>
<a name="Examples-52"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-52">31.11.1 Examples</a></h3>
<ul>
<li>
Output the input file audio and the corresponding video representation
at the same time:
<table><tr><td>&nbsp;</td><td><pre class="example">amovie=a.mp3,asplit[out0],showwaves[out1]
</pre></td></tr></table>
</li><li>
Create a synthetic signal and show it with showwaves, forcing a
frame rate of 30 frames per second:
<table><tr><td>&nbsp;</td><td><pre class="example">aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
</pre></td></tr></table>
</li></ul>
<a name="split_002c-asplit"></a>
<h2 class="section"><a href="ffplay-all.html#toc-split_002c-asplit">31.12 split, asplit</a></h2>
<p>Split input into several identical outputs.
</p>
<p><code>asplit</code> works with audio input, <code>split</code> with video.
</p>
<p>The filter accepts a single parameter which specifies the number of outputs. If
unspecified, it defaults to 2.
</p>
<a name="Examples-7"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-7">31.12.1 Examples</a></h3>
<ul>
<li>
Create two separate outputs from the same input:
<table><tr><td>&nbsp;</td><td><pre class="example">[in] split [out0][out1]
</pre></td></tr></table>
</li><li>
To create 3 or more outputs, you need to specify the number of
outputs, like in:
<table><tr><td>&nbsp;</td><td><pre class="example">[in] asplit=3 [out0][out1][out2]
</pre></td></tr></table>
</li><li>
Create two separate outputs from the same input, one cropped and
one padded:
<table><tr><td>&nbsp;</td><td><pre class="example">[in] split [splitout1][splitout2];
[splitout1] crop=100:100:0:0 [cropout];
[splitout2] pad=200:200:100:100 [padout];
</pre></td></tr></table>
</li><li>
Create 5 copies of the input audio with <code>ffmpeg</code>:
<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
</pre></td></tr></table>
</li></ul>
<a name="zmq_002c-azmq"></a>
<h2 class="section"><a href="ffplay-all.html#toc-zmq_002c-azmq">31.13 zmq, azmq</a></h2>
<p>Receive commands sent through a libzmq client, and forward them to
filters in the filtergraph.
</p>
<p><code>zmq</code> and <code>azmq</code> work as a pass-through filters. <code>zmq</code>
must be inserted between two video filters, <code>azmq</code> between two
audio filters.
</p>
<p>To enable these filters you need to install the libzmq library and
headers and configure FFmpeg with <code>--enable-libzmq</code>.
</p>
<p>For more information about libzmq see:
<a href="http://www.zeromq.org/">http://www.zeromq.org/</a>
</p>
<p>The <code>zmq</code> and <code>azmq</code> filters work as a libzmq server, which
receives messages sent through a network interface defined by the
&lsquo;<samp>bind_address</samp>&rsquo; option.
</p>
<p>The received message must be in the form:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>TARGET</var> <var>COMMAND</var> [<var>ARG</var>]
</pre></td></tr></table>
<p><var>TARGET</var> specifies the target of the command, usually the name of
the filter class or a specific filter instance name.
</p>
<p><var>COMMAND</var> specifies the name of the command for the target filter.
</p>
<p><var>ARG</var> is optional and specifies the optional argument list for the
given <var>COMMAND</var>.
</p>
<p>Upon reception, the message is processed and the corresponding command
is injected into the filtergraph. Depending on the result, the filter
will send a reply to the client, adopting the format:
</p><table><tr><td>&nbsp;</td><td><pre class="example"><var>ERROR_CODE</var> <var>ERROR_REASON</var>
<var>MESSAGE</var>
</pre></td></tr></table>
<p><var>MESSAGE</var> is optional.
</p>
<a name="Examples-82"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-82">31.13.1 Examples</a></h3>
<p>Look at &lsquo;<tt>tools/zmqsend</tt>&rsquo; for an example of a zmq client which can
be used to send commands processed by these filters.
</p>
<p>Consider the following filtergraph generated by <code>ffplay</code>
</p><table><tr><td>&nbsp;</td><td><pre class="example">ffplay -dumpgraph 1 -f lavfi &quot;
color=s=100x100:c=red [l];
color=s=100x100:c=blue [r];
nullsrc=s=200x100, zmq [bg];
[bg][l] overlay [bg+l];
[bg+l][r] overlay=x=100 &quot;
</pre></td></tr></table>
<p>To change the color of the left side of the video, the following
command can be used:
</p><table><tr><td>&nbsp;</td><td><pre class="example">echo Parsed_color_0 c yellow | tools/zmqsend
</pre></td></tr></table>
<p>To change the right side:
</p><table><tr><td>&nbsp;</td><td><pre class="example">echo Parsed_color_1 c pink | tools/zmqsend
</pre></td></tr></table>
<a name="Multimedia-Sources"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Multimedia-Sources">32. Multimedia Sources</a></h1>
<p>Below is a description of the currently available multimedia sources.
</p>
<a name="amovie"></a>
<h2 class="section"><a href="ffplay-all.html#toc-amovie">32.1 amovie</a></h2>
<p>This is the same as <a href="#movie">movie</a> source, except it selects an audio
stream by default.
</p>
<p><a name="movie"></a>
</p><a name="movie-1"></a>
<h2 class="section"><a href="ffplay-all.html#toc-movie-1">32.2 movie</a></h2>
<p>Read audio and/or video stream(s) from a movie container.
</p>
<p>This filter accepts the following options:
</p>
<dl compact="compact">
<dt> &lsquo;<samp>filename</samp>&rsquo;</dt>
<dd><p>The name of the resource to read (not necessarily a file but also a device or a
stream accessed through some protocol).
</p>
</dd>
<dt> &lsquo;<samp>format_name, f</samp>&rsquo;</dt>
<dd><p>Specifies the format assumed for the movie to read, and can be either
the name of a container or an input device. If not specified the
format is guessed from <var>movie_name</var> or by probing.
</p>
</dd>
<dt> &lsquo;<samp>seek_point, sp</samp>&rsquo;</dt>
<dd><p>Specifies the seek point in seconds, the frames will be output
starting from this seek point, the parameter is evaluated with
<code>av_strtod</code> so the numerical value may be suffixed by an IS
postfix. Default value is &quot;0&quot;.
</p>
</dd>
<dt> &lsquo;<samp>streams, s</samp>&rsquo;</dt>
<dd><p>Specifies the streams to read. Several streams can be specified,
separated by &quot;+&quot;. The source will then have as many outputs, in the
same order. The syntax is explained in the &ldquo;Stream specifiers&rdquo;
section in the ffmpeg manual. Two special names, &quot;dv&quot; and &quot;da&quot; specify
respectively the default (best suited) video and audio stream. Default
is &quot;dv&quot;, or &quot;da&quot; if the filter is called as &quot;amovie&quot;.
</p>
</dd>
<dt> &lsquo;<samp>stream_index, si</samp>&rsquo;</dt>
<dd><p>Specifies the index of the video stream to read. If the value is -1,
the best suited video stream will be automatically selected. Default
value is &quot;-1&quot;. Deprecated. If the filter is called &quot;amovie&quot;, it will select
audio instead of video.
</p>
</dd>
<dt> &lsquo;<samp>loop</samp>&rsquo;</dt>
<dd><p>Specifies how many times to read the stream in sequence.
If the value is less than 1, the stream will be read again and again.
Default value is &quot;1&quot;.
</p>
<p>Note that when the movie is looped the source timestamps are not
changed, so it will generate non monotonically increasing timestamps.
</p></dd>
</dl>
<p>This filter allows one to overlay a second video on top of main input of
a filtergraph as shown in this graph:
</p><table><tr><td>&nbsp;</td><td><pre class="example">input -----------&gt; deltapts0 --&gt; overlay --&gt; output
^
|
movie --&gt; scale--&gt; deltapts1 -------+
</pre></td></tr></table>
<a name="Examples-17"></a>
<h3 class="subsection"><a href="ffplay-all.html#toc-Examples-17">32.2.1 Examples</a></h3>
<ul>
<li>
Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
on top of the input labelled as &quot;in&quot;:
<table><tr><td>&nbsp;</td><td><pre class="example">movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
[in] setpts=PTS-STARTPTS [main];
[main][over] overlay=16:16 [out]
</pre></td></tr></table>
</li><li>
Read from a video4linux2 device, and overlay it on top of the input
labelled as &quot;in&quot;:
<table><tr><td>&nbsp;</td><td><pre class="example">movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
[in] setpts=PTS-STARTPTS [main];
[main][over] overlay=16:16 [out]
</pre></td></tr></table>
</li><li>
Read the first video stream and the audio stream with id 0x81 from
dvd.vob; the video is connected to the pad named &quot;video&quot; and the audio is
connected to the pad named &quot;audio&quot;:
<table><tr><td>&nbsp;</td><td><pre class="example">movie=dvd.vob:s=v:0+#0x81 [video] [audio]
</pre></td></tr></table>
</li></ul>
<a name="See-Also"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-See-Also">33. See Also</a></h1>
<p><a href="ffplay.html">ffplay</a>,
<a href="ffmpeg.html">ffmpeg</a>, <a href="ffprobe.html">ffprobe</a>, <a href="ffserver.html">ffserver</a>,
<a href="ffmpeg-utils.html">ffmpeg-utils</a>,
<a href="ffmpeg-scaler.html">ffmpeg-scaler</a>,
<a href="ffmpeg-resampler.html">ffmpeg-resampler</a>,
<a href="ffmpeg-codecs.html">ffmpeg-codecs</a>,
<a href="ffmpeg-bitstream-filters.html">ffmpeg-bitstream-filters</a>,
<a href="ffmpeg-formats.html">ffmpeg-formats</a>,
<a href="ffmpeg-devices.html">ffmpeg-devices</a>,
<a href="ffmpeg-protocols.html">ffmpeg-protocols</a>,
<a href="ffmpeg-filters.html">ffmpeg-filters</a>
</p>
<a name="Authors"></a>
<h1 class="chapter"><a href="ffplay-all.html#toc-Authors">34. Authors</a></h1>
<p>The FFmpeg developers.
</p>
<p>For details about the authorship, see the Git history of the project
(git://source.ffmpeg.org/ffmpeg), e.g. by typing the command
<code>git log</code> in the FFmpeg source directory, or browsing the
online repository at <a href="http://source.ffmpeg.org">http://source.ffmpeg.org</a>.
</p>
<p>Maintainers for the specific components are listed in the file
&lsquo;<tt>MAINTAINERS</tt>&rsquo; in the source code tree.
</p>
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