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Fixed MP3 length detection when there is no VBR header by performing a full file walk

CQTexperiment
Chris Moeller 2013-10-30 11:58:07 -07:00
parent 557e48253d
commit 2badd3dbff
1 changed files with 42 additions and 0 deletions
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42
Frameworks/FFMPEG/ffmpeg-minimal/libavformat/mp3dec.c
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@ -29,6 +29,7 @@
#include "internal.h"
#include "id3v2.h"
#include "id3v1.h"
#include "apetag.h"
#include "libavcodec/mpegaudiodecheader.h"
#define XING_FLAG_FRAMES 0x01
@ -274,7 +275,48 @@ static int mp3_read_header(AVFormatContext *s)
mp3->filesize = avio_size(s->pb);
if (mp3_parse_vbr_tags(s, st, off) < 0)
{
uint64_t duration = 0;
uint8_t buf[8];
int sample_rate = 0;
/* Time for a full parse! */
avio_seek(s->pb, -128, SEEK_END);
avio_read(s->pb, buf, 3);
if (buf[0] == 'T' && buf[1] == 'A' && buf[2] == 'G')
mp3->filesize -= 128;
avio_seek(s->pb, mp3->filesize - APE_TAG_FOOTER_BYTES, SEEK_SET);
avio_read(s->pb, buf, 8);
if (memcmp(buf, APE_TAG_PREAMBLE, 8) == 0)
{
avio_seek(s->pb, 4, SEEK_CUR);
mp3->filesize -= avio_rl32(s->pb) + APE_TAG_FOOTER_BYTES;
}
avio_seek(s->pb, off, SEEK_SET);
while (avio_tell(s->pb) < mp3->filesize)
{
MPADecodeHeader c;
uint32_t v, spf;
v = avio_rb32(s->pb);
if(ff_mpa_check_header(v) < 0)
break;
if (avpriv_mpegaudio_decode_header(&c, v) != 0)
break;
if (!sample_rate)
sample_rate = c.sample_rate;
spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
duration += spf;
avio_skip(s->pb, c.frame_size - 4);
}
avio_seek(s->pb, off, SEEK_SET);
st->duration = av_rescale_q(duration, (AVRational){1, sample_rate}, st->time_base);
}
/* the parameters will be extracted from the compressed bitstream */
return 0;