generic-library/ffmpeg
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

mp3dec: Fix VBR bit rate parsing

Browse Source 
When parsing the Xing/Info tag, don't set the bit rate if it's an Info tag.

When parsing the stream, don't override the bit rate if it's already set,
otherwise calculate the mean bit rate from parsed frames. This way, the bit
rate will be set correctly both for CBR and VBR streams.

Signed-off-by: Alexander Kojevnikov <alexander@kojevnikov.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 29d8cd265a)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Alexander Kojevnikov
2013-02-26 21:47:11 -08:00
committed by Michael Niedermayer
parent f49b2a9d08
commit 7fc39f51cd
3 changed files with 13 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
libavcodec/mpegaudio_parser.c
View File

@@ -30,6 +30,7 @@ typedef struct MpegAudioParseContext {
int frame_size; int frame_size;
uint32_t header; uint32_t header;
int header_count; int header_count;
int no_bitrate;
} MpegAudioParseContext; } MpegAudioParseContext;
#define MPA_HEADER_SIZE 4 #define MPA_HEADER_SIZE 4
@@ -74,15 +75,18 @@ static int mpegaudio_parse(AVCodecParserContext *s1,
if((state&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header) if((state&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header)
s->header_count= -3; s->header_count= -3;
s->header= state; s->header= state;
s->header_count++;
s->frame_size = ret-4; s->frame_size = ret-4;
if (s->header_count > 1) { if (s->header_count > 0) {
avctx->sample_rate= sr; avctx->sample_rate= sr;
avctx->channels = channels; avctx->channels = channels;
s1->duration = frame_size; s1->duration = frame_size;
avctx->bit_rate = bit_rate; if (s->no_bitrate || !avctx->bit_rate) {
s->no_bitrate = 1;
avctx->bit_rate += (bit_rate - avctx->bit_rate) / s->header_count;
} }
}
s->header_count++;
break; break;
} }
} }

6
libavformat/mp3dec.c
View File

@@ -120,6 +120,7 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}}; const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
MPADecodeHeader c; MPADecodeHeader c;
int vbrtag_size = 0; int vbrtag_size = 0;
int is_cbr;
v = avio_rb32(s->pb); v = avio_rb32(s->pb);
if(ff_mpa_check_header(v) < 0) if(ff_mpa_check_header(v) < 0)
@@ -135,7 +136,8 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
/* Check for Xing / Info tag */ /* Check for Xing / Info tag */
avio_skip(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1]); avio_skip(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1]);
v = avio_rb32(s->pb); v = avio_rb32(s->pb);
if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) { is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
if (v == MKBETAG('X', 'i', 'n', 'g') || is_cbr) {
v = avio_rb32(s->pb); v = avio_rb32(s->pb);
if(v & XING_FLAG_FRAMES) if(v & XING_FLAG_FRAMES)
frames = avio_rb32(s->pb); frames = avio_rb32(s->pb);
@@ -180,7 +182,7 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
if(frames) if(frames)
st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate}, st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
st->time_base); st->time_base);
if(size && frames) if (size && frames && !is_cbr)
st->codec->bit_rate = av_rescale(size, 8 * c.sample_rate, frames * (int64_t)spf); st->codec->bit_rate = av_rescale(size, 8 * c.sample_rate, frames * (int64_t)spf);
return 0; return 0;

4
tests/ref/lavf-fate/mp3
View File

@@ -1,3 +1,3 @@
40a4e41ae74ec8dacdf02402831a6a58 *./tests/data/lavf-fate/lavf.mp3 7fcf80c2059b5c058a6cdd2e2f798b6c *./tests/data/lavf-fate/lavf.mp3
97230 ./tests/data/lavf-fate/lavf.mp3 96366 ./tests/data/lavf-fate/lavf.mp3
./tests/data/lavf-fate/lavf.mp3 CRC=0x6c9850fe ./tests/data/lavf-fate/lavf.mp3 CRC=0x6c9850fe