By default, the synthesizer outputs a single stereo signal. Using this option, the synthesizer can output multi-channel audio. Sets the number of stereo channel pairs. So 1 is actually 2 channels (a stereo pair).</desc>
The output audio channel associated with a MIDI channel is wrapped around using the number of synth.audio-groups as modulo divider. This is typically the number of output channels on the sound card, as long as the LADSPA Fx unit is not used. In case of LADSPA unit, think of it as subgroups on a mixer.</desc>
When set to 1 (TRUE) the chorus effects module is activated. Otherwise, no chorus will be added to the output signal. Note that the amount of signal sent to the chorus module depends on the "chorus send" generator defined in the SoundFont.</desc>
Sets the number of synthesis CPU cores. If set to a value greater than 1, additional synthesis threads will be created to do the actual rendering work that is then returned synchronously by the render function. This has the affect of utilizing more of the total CPU for voices or decreasing render times when synthesizing audio.
So for example, if you set cpu-cores to 4, fluidsynth will attempt to split the synthesis work it needs to do between the client's calling thread and three additional (internal) worker threads. As soon as all threads have done their work, their results are collected and the resulting buffer is returned to the caller.
The default soundfont file to use by the fluidsynth executable. The default value can be overridden during compilation time by setting the DEFAULT_SOUNDFONT cmake variable.</desc>
Device identifier used for SYSEX commands, such as MIDI Tuning Standard commands. Fluidsynth will only process those SYSEX commands destined for this ID. Broadcast commands (with ID=127) will always be processed.</desc>
<desc>Specifies the number of effects per effects group. Currently this value can not be changed so there are always two effects per group available (reverb and chorus).</desc>
<desc>Specifies the number of effects groups. By default, the sound of all voices is rendered by one reverb and one chorus effect respectively (even for multi-channel rendering). This setting gives the user control which effects of a voice to render to which independent audio channels. E.g. setting synth.effects-groups == synth.midi-channels allows to render the effects of each MIDI channel to separate audio buffers. If synth.effects-groups is smaller than the number of MIDI channels, it will wrap around. Note that any value >1 will significantly increase CPU usage.</desc>
<desc>The gain is applied to the final or master output of the synthesizer. It is set to a low value by default to avoid the saturation of the output when many notes are played.</desc>
When set to 1 (TRUE) the LADSPA subsystem will be enabled. This subsystem allows to load and interconnect LADSPA plug-ins. The output of the synthesizer is processed by the LADSPA subsystem. Note that the synthesizer has to be compiled with LADSPA support. More information about the LADSPA subsystem can be found in doc/ladspa.md or on the FluidSynth website.</desc>
This setting defines the number of MIDI channels of the synthesizer. The MIDI standard defines 16 channels, so MIDI hardware is limited to this number. Internally FluidSynth can use more channels which can be mapped to different MIDI sources.</desc>
Sets the minimum note duration in milliseconds. This ensures that really short duration note events, such as percussion notes, have a better chance of sounding as intended. Set to 0 to disable this feature.</desc>
The polyphony defines how many voices can be played in parallel. A note event produces one or more voices. Its good to set this to a value which the system can handle and will thus limit FluidSynth's CPU usage. When FluidSynth runs out of voices it will begin terminating lower priority voices for new note events.</desc>
When set to 1 (TRUE) the reverb effects module is activated. Otherwise, no reverb will be added to the output signal. Note that the amount of signal sent to the reverb module depends on the "reverb send" generator defined in the SoundFont.
The sample rate of the audio generated by the synthesizer. For optimal performance, make sure this value equals the native output rate of the audio driver (in case you are using any of fluidsynth's audio drivers). Some drivers, such as Oboe, will interpolate sample-rates, whereas others, such as Jack, will override this setting, if a mismatch with the native output rate is detected.
Controls whether the synth's public API is protected by a mutex or not. Default is on, turn it off for slightly better performance if you know you're only accessing the synth from one thread only, this could be the case in many embedded use cases for example. Note that libfluidsynth can use many threads by itself (shell is one, midi driver is one, midi player is one etc) so you should usually leave it on.
When set to 1 (TRUE) the synthesizer will print out information about the received MIDI events to the stdout. This can be helpful for debugging. This setting cannot be changed after the synthesizer has started.
The audio system to be used. In order to use sdl2 as audio driver, the application is responsible for initializing SDL's audio subsystem.<br/><br/><strong>Note:</strong> sdl2 and waveout are available since fluidsynth 2.1.
The number of the audio buffers used by the driver. This number of buffers, multiplied by the buffer size (see setting audio.period-size), determines the maximum latency of the audio driver.
Sets the realtime scheduling priority of the audio synthesis thread. This includes the synthesis threads created by the synth (in case synth.cpu-cores was greater 1). A value of 0 disables high priority scheduling. Linux is the only platform which currently makes use of different priority levels as specified by this setting. On other operating systems the thread priority is set to maximum. Drivers which use this option: alsa, oss and pulseaudio
The format of the audio samples. This is currently only an indication; the audio driver may ignore this setting if it can't handle the specified format.
<def>'auto' if libsndfile support is built in,<br/>
'cpu' otherwise.</def>
<vals>auto, big, cpu, little ('cpu' is all that is supported if libsndfile support is not built in)</vals>
<desc>
Defines the byte order when using the 'file' driver or file renderer to store audio to a file. 'auto' uses the default for the given file type, 'cpu' uses the CPU byte order, 'big' uses big endian byte order and 'little' uses little endian byte order.
Sets the file type of the file which the audio will be stored to. 'auto' attempts to determine the file type from the audio.file.name file extension and falls back to 'wav' if the extension doesn't match any types. Limited to 'raw' if compiled without libsndfile support. Actual options will vary depending on libsndfile library.
Device to use for PortAudio driver output. Note that 'PortAudio Default' is a special value which outputs to the default PortAudio device. The format of the device name is: "<device_index>:<host_api_name>:<host_device_name>" e.g. "11:Windows DirectSound:SB PCI"
If TRUE initializes the maximum length of the audio buffer to the highest supported value and increases the latency dynamically if PulseAudio suggests so. Else uses a buffer with length of "audio.period-size".
If 1 (TRUE), automatically connects FluidSynth to available MIDI input ports. alsa_seq, coremidi and jack are currently the only drivers making use of this.
<desc>Sets the realtime scheduling priority of the MIDI thread (0 disables high priority scheduling). Linux is the only platform which currently makes use of different priority levels. Drivers which use this option: alsa_raw, alsa_seq, oss</desc>
<desc>ID to use when registering ports with the ALSA sequencer driver. If set to "pid" then the ID will be "FLUID Synth (PID)", where PID is the FluidSynth process ID of the audio thread otherwise the provided string will be used in place of PID.</desc>
<desc>Client ID to use with the Jack MIDI driver. If jack is also used as audio driver and "midi.jack.server" and "audio.jack.server" are equal, this setting will be overridden by "audio.jack.id", because a client cannot have multiple names.</desc>
<desc>The hardware device to use for Windows MIDI driver (not to be confused with the MIDI port). Multiple devices can be specified by a list of devices index separated by a semicolon (e.g "2;0", which is equivalent to one device with 32 MIDI channels).</desc>
<desc>If true, reset the synth before starting a new MIDI song, so the state of a previous song can't affect the new song. Turn it off for seamless looping of a song.</desc>
</setting>
<setting>
<name>timing-source</name>
<type>str</type>
<def>sample</def>
<vals>sample, system</vals>
<desc>Determines the timing source of the player sequencer. 'sample' uses the sample clock (how much audio has been output) to sequence events, in which case audio is synchronized with MIDI events. 'system' uses the system clock, audio and MIDI are not synchronized exactly.</desc>
<desc>In dump mode we set the prompt to "" (empty string). The ui cannot easily handle lines, which don't end with cr. Changing the prompt cannot be done through a command, because the current shell does not handle empty arguments.</desc>