[FFmpeg-cvslog] lavf/mp3enc: support MPEG-2 and MPEG-2. 5 sample rates when writing Xing header.
Clément Bœsch
git at videolan.org
Sun May 13 16:49:22 CEST 2012
ffmpeg | branch: master | Clément Bœsch <ubitux at gmail.com> | Wed May 9 22:39:40 2012 +0200| [ca297513f034198029084b4af33ac4c29ab83bce] | committer: Clément Bœsch
lavf/mp3enc: support MPEG-2 and MPEG-2.5 sample rates when writing Xing header.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ca297513f034198029084b4af33ac4c29ab83bce
---
libavformat/mp3enc.c | 18 +++++++++++-------
1 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/libavformat/mp3enc.c b/libavformat/mp3enc.c
index 7dec824..8a9f788 100644
--- a/libavformat/mp3enc.c
+++ b/libavformat/mp3enc.c
@@ -121,17 +121,21 @@ static int mp3_write_xing(AVFormatContext *s)
int64_t xing_offset;
int32_t header, mask;
MPADecodeHeader c;
- int srate_idx, i, channels;
+ int srate_idx, ver = 0, i, channels;
int needed;
if (!s->pb->seekable)
return 0;
- for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++)
- if (avpriv_mpa_freq_tab[i] == codec->sample_rate) {
- srate_idx = i;
- break;
- }
+ for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++) {
+ const uint16_t base_freq = avpriv_mpa_freq_tab[i];
+ if (codec->sample_rate == base_freq) ver = 0x3; // MPEG 1
+ else if (codec->sample_rate == base_freq / 2) ver = 0x2; // MPEG 2
+ else if (codec->sample_rate == base_freq / 4) ver = 0x0; // MPEG 2.5
+ else continue;
+ srate_idx = i;
+ break;
+ }
if (i == FF_ARRAY_ELEMS(avpriv_mpa_freq_tab)) {
av_log(s, AV_LOG_WARNING, "Unsupported sample rate, not writing Xing header.\n");
return -1;
@@ -145,7 +149,7 @@ static int mp3_write_xing(AVFormatContext *s)
/* dummy MPEG audio header */
header = 0xff << 24; // sync
- header |= (0x7 << 5 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
+ header |= (0x7 << 5 | ver << 3 | 0x1 << 1 | 0x1) << 16; // sync/audio-version/layer 3/no crc*/
header |= (srate_idx << 2) << 8;
header |= channels << 6;
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