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snd_mp3.c: better skipping of tags:

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( also see: https://bugzilla.libsdl.org/show_bug.cgi?id=4728 )

Instead of doing it 'as-we-go' every time, skip the tags at file-open
time only once.

The former implementation had the chance of not having the full tag in
the frame, that includes a possibility of even not having the complete
tag magic in the frame leading to not identifying a tag.

The new implementation skips all the tags at file-start and file-end,
and does that only once.

Also added are detection and skipping of extended ID3v1 and APEv1 tags.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1612 af15c1b1-3010-417e-b628-4374ebc0bcbd
This commit is contained in:
Ozkan Sezer 2019-07-23 14:11:30 +00:00
parent ee831b2b48
commit 9fc3408391
1 changed files with 167 additions and 91 deletions
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258
Quake/snd_mp3.c
View file

@ -5,10 +5,10 @@
* with the decoding part based on the decoder tutorial program madlld
* written by Bertrand Petit <madlld@phoe.fmug.org> (BSD license, see at
* http://www.bsd-dk.dk/~elrond/audio/madlld/). The tag identification
* functions were adapted from the GPL-licensed libid3tag library, see at
* http://www.underbit.com/products/mad/. Adapted to Quake and Hexen II
* game engines by O.Sezer :
* Copyright (C) 2010-2015 O.Sezer <sezero@users.sourceforge.net>
* functions were initially adapted from GPL-licensed libid3tag library
* (see at http://www.underbit.com/products/mad/) then rephrased further.
* Adapted for use in Quake and Hexen II game engines by O.Sezer:
* Copyright (C) 2010-2019 O.Sezer <sezero@users.sourceforge.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -34,8 +34,6 @@
#include "snd_mp3.h"
#include <mad.h>
#define ID3_TAG_FLAG_FOOTERPRESENT 0x10
/* Under Windows, importing data from DLLs is a dicey proposition. This is true
* when using dlopen, but also true if linking directly against the DLL if the
* header does not mark the data as __declspec(dllexport), which mad.h does not.
@ -64,9 +62,7 @@ typedef struct _mp3_priv_t
size_t FrameCount;
} mp3_priv_t;
/* This function merges the functions tagtype() and id3_tag_query()
* from MAD's libid3tag, so we don't have to link to it
* Returns 0 if the frame is not an ID3 tag, tag length if it is */
/* http://id3.org/ID3v1 : 3 bytes "TAG" identifier and 125 bytes tag data */
static inline qboolean tag_is_id3v1(const unsigned char *data, size_t length)
{
if (length >= 3 &&
@ -77,11 +73,32 @@ static inline qboolean tag_is_id3v1(const unsigned char *data, size_t length)
return false;
}
/* ID3v1 extended tag: just before ID3v1, always 227 bytes.
* https://www.getid3.org/phpBB3/viewtopic.php?t=1202
* https://en.wikipedia.org/wiki/ID3v1#Enhanced_tag
* Not an official standard, is only supported by few programs. */
static inline qboolean tag_is_id3v1ext(const unsigned char *data, size_t length)
{
if (length >= 4 &&
data[0] == 'T' && data[1] == 'A' && data[2] == 'G' && data[3] == '+')
{
return true;
}
return false;
}
#define ID3_TAG_FLAG_FOOTERPRESENT 0x10
static inline qboolean tag_is_id3v2(const unsigned char *data, size_t length)
{
/* ID3v2 header is 10 bytes: http://id3.org/id3v2.4.0-structure */
if (length >= 10 &&
/* bytes 0-2: "ID3" identifier */
(data[0] == 'I' && data[1] == 'D' && data[2] == '3') &&
/* bytes 3-4: version num (major,revision), each byte always less than 0xff. */
data[3] < 0xff && data[4] < 0xff &&
/* bytes 6-9 are the ID3v2 tag size: a 32 bit 'synchsafe' integer, i.e. the
* highest bit 7 in each byte zeroed. i.e.: 7 bit information in each byte ->
* effectively a 28 bit value. */
data[6] < 0x80 && data[7] < 0x80 && data[8] < 0x80 && data[9] < 0x80)
{
return true;
@ -89,9 +106,25 @@ static inline qboolean tag_is_id3v2(const unsigned char *data, size_t length)
return false;
}
static inline long get_id3v2_len(const unsigned char *data, long datalen)
{
/* size is a 'synchsafe' integer (see above) */
long taglen = (long)((data[6]<<21) + (data[7]<<14) + (data[8]<<7) + data[9]);
taglen += 10; /* header size */
/* ID3v2 header[5] is flags (bits 4-7 only, 0-3 are zero).
* bit 4 set: footer is present (a copy of the header but
* with "3DI" as ident.) */
if (data[5] & ID3_TAG_FLAG_FOOTERPRESENT)
taglen += 10;
for ( ; taglen < datalen && !data[taglen]; ++taglen)
; /* consume optional padding (always zeroes) */
return taglen;
}
/* http://wiki.hydrogenaud.io/index.php?title=APEv1_specification
* http://wiki.hydrogenaud.io/index.php?title=APEv2_specification
* Detect an APEv2 tag. (APEv1 has no header, so no luck.)
* Header/footer is 32 bytes: bytes 0-7 ident, bytes 8-11 version,
* bytes 12-17 size. bytes 24-31 are reserved: must be all zeroes.
*/
static inline qboolean tag_is_apetag(const unsigned char *data, size_t length)
{
@ -101,7 +134,7 @@ static inline qboolean tag_is_apetag(const unsigned char *data, size_t length)
if (memcmp(data,"APETAGEX",8) != 0)
return false;
v = (data[11]<<24) | (data[10]<<16) | (data[9]<<8) | data[8];
if (v != 2000U/* && v != 1000U*/)
if (v != 2000U && v != 1000U)
return false;
v = 0;
if (memcmp(&data[24],&v,4) != 0 || memcmp(&data[28],&v,4) != 0)
@ -109,70 +142,127 @@ static inline qboolean tag_is_apetag(const unsigned char *data, size_t length)
return true;
}
static size_t mp3_tagsize(const unsigned char *data, size_t length)
static inline long get_ape_len(const unsigned char *data, long datalen, unsigned int *version)
{
size_t size;
if (tag_is_id3v1(data, length))
return 128;
if (tag_is_id3v2(data, length))
{
unsigned char flags = data[5];
size = 10 + (data[6]<<21) + (data[7]<<14) + (data[8]<<7) + data[9];
if (flags & ID3_TAG_FLAG_FOOTERPRESENT)
size += 10;
for ( ; size < length && !data[size]; ++size)
; /* Consume padding */
return size;
}
if (tag_is_apetag(data, length))
{
size = (data[15]<<24) | (data[14]<<16) | (data[13]<<8) | data[12];
size += 32;
return size;
}
return 0;
long taglen = (long)((data[15]<<24) | (data[14]<<16) | (data[13]<<8) | data[12]);
*version = (data[11]<<24) | (data[10]<<16) | (data[9]<<8) | data[8];
return taglen; /* caller will handle the additional v2 header length */
}
/* Attempts to read an ID3 tag at the current location in stream and
* consume it all. Returns -1 if no tag is found. Its up to caller
* to recover. */
static int mp3_inputtag(snd_stream_t *stream)
static int skip_tags_first(snd_stream_t *stream, unsigned char *buf, size_t bufsize)
{
mp3_priv_t *p = (mp3_priv_t *) stream->priv;
int rc = -1;
size_t remaining;
size_t tagsize;
long len; size_t readsize;
/* FIXME: This needs some more work if we are to ever
* look at the ID3 frame. This is because the Stream
* may not be able to hold the complete ID3 frame.
* We should consume the whole frame inside tagtype()
* instead of outside of tagframe(). That would support
* recovering when Stream contains less then 8-bytes (header)
* and also when ID3v2 is bigger then Stream buffer size.
* Need to pass in stream so that buffer can be
* consumed as well as letting additional data to be
* read in.
*/
remaining = p->Stream.bufend - p->Stream.next_frame;
tagsize = mp3_tagsize(p->Stream.this_frame, remaining);
if (tagsize != 0)
readsize = FS_fread(buf, 1, bufsize, &stream->fh);
if (!readsize || FS_ferror(&stream->fh))
return -1;
/* ID3v2 tag is at the start */
if (tag_is_id3v2(buf, readsize))
{
mad_stream_skip(&p->Stream, tagsize);
rc = 0;
len = get_id3v2_len(buf, (long)readsize);
if (len >= stream->fh.length) return -1;
/* hack the fshandle_t start pos and length members */
stream->fh.start += len;
stream->fh.length -= len;
FS_rewind(&stream->fh);
Con_DPrintf("MP3: skipped %ld bytes ID3v2 tag\n", len);
}
/* APE tag _might_ be at the start: read the header */
else if (tag_is_apetag(buf, readsize))
{
unsigned int v;
len = get_ape_len(buf, (long)readsize, &v);
len += 32; /* we're at top: have a header. */
if (len >= stream->fh.length) return -1;
/* hack the fshandle_t start pos and length members */
stream->fh.start += len;
stream->fh.length -= len;
FS_rewind(&stream->fh);
Con_DPrintf("MP3: skipped %ld bytes APEv2 tag\n", len);
}
/* We know that a valid frame hasn't been found yet
* so help libmad out and go back into frame seek mode.
* This is true whether an ID3 tag was found or not.
*/
mad_stream_sync(&p->Stream);
/* ID3v1 tag is at the end */
if (stream->fh.length < 128)
goto ape;
FS_fseek(&stream->fh, -128, SEEK_END);
readsize = FS_fread(buf, 1, 128, &stream->fh);
FS_rewind(&stream->fh);
if (readsize != 128) return -1;
if (tag_is_id3v1(buf, 128))
{
/* hack fshandle_t->length */
stream->fh.length -= 128;
Con_DPrintf("MP3: skipped ID3v1 tag\n");
return rc;
/* APE tag may be before the ID3v1: read the footer */
if (stream->fh.length < 32)
goto end;
FS_fseek(&stream->fh, -32, SEEK_END);
readsize = FS_fread(buf, 1, 32, &stream->fh);
FS_rewind(&stream->fh);
if (readsize != 32) return -1;
if (tag_is_apetag(buf, 32))
{
unsigned int v;
len = get_ape_len(buf, (long)readsize, &v);
if (v == 2000U) len += 32; /* header */
if (len >= stream->fh.length) return -1;
if (v == 2000U) { /* verify header : */
FS_fseek(&stream->fh, -len, SEEK_END);
readsize = FS_fread(buf, 1, 32, &stream->fh);
FS_rewind(&stream->fh);
if (readsize != 32) return -1;
if (!tag_is_apetag(buf, 32)) return -1;
}
/* hack fshandle_t->length */
stream->fh.length -= len;
Con_DPrintf("MP3: skipped %ld bytes APEv%u tag\n", len, v/1000);
goto end;
}
/* extended ID3v1 just before the ID3v1 tag? (unlikely) */
if (stream->fh.length < 227)
goto end;
FS_fseek(&stream->fh, -227, SEEK_END);
readsize = FS_fread(buf, 1, 227, &stream->fh);
FS_rewind(&stream->fh);
if (readsize != 227) return -1;
if (tag_is_id3v1ext(buf, 227))
{
/* hack fshandle_t->length */
stream->fh.length -= 227;
Con_DPrintf("MP3: skipped ID3v1 extended tag\n");
goto end;
}
}
ape: /* APE tag may be at the end: read the footer */
if (stream->fh.length >= 32)
{
FS_fseek(&stream->fh, -32, SEEK_END);
readsize = FS_fread(buf, 1, 32, &stream->fh);
FS_rewind(&stream->fh);
if (readsize != 32) return -1;
if (tag_is_apetag(buf, 32))
{
unsigned int v;
len = get_ape_len(buf, (long)readsize, &v);
if (v == 2000U) len += 32; /* header */
if (len >= stream->fh.length) return -1;
if (v == 2000U) { /* verify header : */
FS_fseek(&stream->fh, -len, SEEK_END);
readsize = FS_fread(buf, 1, 32, &stream->fh);
FS_rewind(&stream->fh);
if (readsize != 32) return -1;
if (!tag_is_apetag(buf, 32)) return -1;
}
/* hack fshandle_t->length */
stream->fh.length -= len;
Con_DPrintf("MP3: skipped %ld bytes APEv%u tag\n", len, v/1000);
}
}
end:
return (stream->fh.length > 0)? 0: -1;
}
/* (Re)fill the stream buffer that is to be decoded. If any data
@ -214,6 +304,10 @@ static int mp3_startread(snd_stream_t *stream)
mp3_priv_t *p = (mp3_priv_t *) stream->priv;
size_t ReadSize;
/* skip tags known to be at start or end and adjust the file */
if (skip_tags_first(stream, p->mp3_buffer, MP3_BUFFER_SIZE) < 0)
return -1;
mad_stream_init(&p->Stream);
mad_frame_init(&p->Frame);
mad_synth_init(&p->Synth);
@ -245,14 +339,10 @@ static int mp3_startread(snd_stream_t *stream)
continue;
}
/* Consume any ID3 tags */
mp3_inputtag(stream);
/* FIXME: We should probably detect when we've read
* a bunch of non-ID3 data and still haven't found a
* frame. In that case we can abort early without
* scanning the whole file.
/* We know that a valid frame hasn't been found yet
* so help libmad out and go back into frame seek mode.
*/
mad_stream_sync(&p->Stream);
p->Stream.error = MAD_ERROR_NONE;
}
@ -353,7 +443,7 @@ static int mp3_decode(snd_stream_t *stream, byte *buf, int len)
{
if (MAD_RECOVERABLE(p->Stream.error))
{
mp3_inputtag(stream);
mad_stream_sync(&p->Stream); /* to frame seek mode */
continue;
}
else
@ -392,7 +482,7 @@ static int mp3_madseek(snd_stream_t *stream, unsigned long offset)
{
mp3_priv_t *p = (mp3_priv_t *) stream->priv;
size_t initial_bitrate = p->Frame.header.bitrate;
size_t tagsize = 0, consumed = 0;
size_t consumed = 0;
int vbr = 0; /* Variable Bit Rate, bool */
qboolean depadded = false;
unsigned long to_skip_samples = 0;
@ -450,21 +540,7 @@ static int mp3_madseek(snd_stream_t *stream, unsigned long offset)
}
if (p->Stream.error == MAD_ERROR_LOSTSYNC)
{
unsigned long available = (p->Stream.bufend - p->Stream.this_frame);
tagsize = mp3_tagsize(p->Stream.this_frame, (size_t) available);
if (tagsize)
{ /* It's some ID3 tags, so just skip */
if (tagsize >= available)
{
FS_fseek(&stream->fh, (long)(tagsize - available), SEEK_CUR);
depadded = false;
}
mad_stream_skip(&p->Stream, q_min(tagsize, available));
}
else
{
Con_DPrintf("MAD lost sync\n");
}
Con_DPrintf("MAD lost sync\n");
}
else
{
@ -495,7 +571,7 @@ static int mp3_madseek(snd_stream_t *stream, unsigned long offset)
{
p->FrameCount = offset / samples;
to_skip_samples = offset % samples;
if (0 != FS_fseek(&stream->fh, (p->FrameCount * consumed / 64) + tagsize, SEEK_SET))
if (0 != FS_fseek(&stream->fh, (p->FrameCount * consumed / 64), SEEK_SET))
return -1;
/* Reset Stream for refilling buffer */