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mp3enc: Fix Xing tag identification string for CBR files

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Fixes the Xing tag identification string to be "Info" for MP3 files with
constant bitrate. The previous "Xing" caused some decoders to recognize the
file as VBR.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Tobias Rapp 2012-05-07 11:55:05 +02:00 committed by Michael Niedermayer
parent 16b9156b7e
commit 8da0a6cda1
1 changed files with 23 additions and 2 deletions
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25
libavformat/mp3enc.c
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@ -94,6 +94,8 @@ typedef struct MP3Context {
uint32_t seen;
uint32_t pos;
uint64_t bag[VBR_NUM_BAGS];
int initial_bitrate;
int has_variable_bitrate;
/* index of the audio stream */
int audio_stream_idx;
@ -238,6 +240,16 @@ static void mp3_fix_xing(AVFormatContext *s)
int i;
avio_flush(s->pb);
/* replace "Xing" identification string with "Info" for CBR files. */
if (!mp3->has_variable_bitrate) {
int64_t tag_offset = mp3->frames_offset
- 4 // frames/size/toc flags
- 4; // xing tag
avio_seek(s->pb, tag_offset, SEEK_SET);
avio_wb32(s->pb, MKBETAG('I', 'n', 'f', 'o'));
}
avio_seek(s->pb, mp3->frames_offset, SEEK_SET);
avio_wb32(s->pb, mp3->frames);
avio_wb32(s->pb, mp3->size);
@ -260,12 +272,21 @@ static int mp3_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
return ff_raw_write_packet(s, pkt);
else {
MP3Context *mp3 = s->priv_data;
#ifdef FILTER_VBR_HEADERS
MPADecodeHeader c;
#ifdef FILTER_VBR_HEADERS
int base;
#endif
ff_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
avpriv_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
if (!mp3->initial_bitrate)
mp3->initial_bitrate = c.bit_rate;
if (!mp3->has_variable_bitrate) {
if ((c.bit_rate == 0) || (mp3->initial_bitrate != c.bit_rate))
mp3->has_variable_bitrate = 1;
}
#ifdef FILTER_VBR_HEADERS
/* filter out XING and INFO headers. */
base = 4 + xing_offtbl[c.lsf == 1][c.nb_channels == 1];