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authorTobias Rapp <t.rapp@noa-audio.com>2012-05-07 11:55:05 +0200
committerMichael Niedermayer <michaelni@gmx.at>2012-05-07 16:24:19 +0200
commit8da0a6cda1bd59471df6a4a18988c2381c05cee7 (patch)
tree04cb4f56e612c47f3566dd149ee4ea93aeb135dc
parent16b9156b7ec3eedf8d5a109f1fb1a103a8b5d6f0 (diff)
downloadffmpeg-8da0a6cda1bd59471df6a4a18988c2381c05cee7.tar.gz
mp3enc: Fix Xing tag identification string for CBR files
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>
-rw-r--r--libavformat/mp3enc.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/libavformat/mp3enc.c b/libavformat/mp3enc.c
index 29c0780b90..415fdba79f 100644
--- a/libavformat/mp3enc.c
+++ b/libavformat/mp3enc.c
@@ -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
+
+ avpriv_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
- ff_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];