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If we find a VBR tag at the beginning of the file don't attempt to

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parse it as a valid frame.
patch by (Yoav Steinberg yoav out monfort in co in il)

Originally committed as revision 16421 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Yoav Steinberg 2009-01-04 16:23:18 +00:00 committed by Michael Niedermayer
parent 1ca9133fb4
commit 853a97530e
1 changed files with 13 additions and 7 deletions
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20
libavformat/mp3.c
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@ -402,20 +402,22 @@ static int mp3_read_probe(AVProbeData *p)
/**
* Try to find Xing/Info/VBRI tags and compute duration from info therein
*/
static void mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
{
uint32_t v, spf;
int frames = -1; /* Total number of frames in file */
const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
MPADecodeContext c;
int vbrtag_size = 0;
v = get_be32(s->pb);
if(ff_mpa_check_header(v) < 0)
return;
return -1;
ff_mpegaudio_decode_header(&c, v);
if (ff_mpegaudio_decode_header(&c, v) == 0)
vbrtag_size = c.frame_size;
if(c.layer != 3)
return;
return -1;
/* Check for Xing / Info tag */
url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
@ -439,11 +441,15 @@ static void mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
}
if(frames < 0)
return;
return -1;
/* Skip the vbr tag frame */
url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
st->time_base);
return 0;
}
static int mp3_read_header(AVFormatContext *s,
@ -493,8 +499,8 @@ static int mp3_read_header(AVFormatContext *s,
}
off = url_ftell(s->pb);
mp3_parse_vbr_tags(s, st, off);
url_fseek(s->pb, off, SEEK_SET);
if (mp3_parse_vbr_tags(s, st, off) < 0)
url_fseek(s->pb, off, SEEK_SET);
/* the parameters will be extracted from the compressed bitstream */
return 0;