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Determine the output sample rate for SBR AAC and write it

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Originally committed as revision 10327 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
David Conrad 2007-09-05 00:23:43 +00:00
parent 6b9a10fbd3
commit 07918a227a
1 changed files with 39 additions and 3 deletions
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42
libavformat/matroskaenc.c
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@ -344,6 +344,37 @@ static int put_xiph_codecpriv(ByteIOContext *pb, AVCodecContext *codec)
return 0;
}
static void get_aac_sample_rates(AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
{
static const int aac_sample_rates[] = {
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000,
};
int sri;
if (codec->extradata_size < 2) {
av_log(codec, AV_LOG_WARNING, "no aac extradata, unable to determine sample rate\n");
return;
}
sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
if (sri > 12) {
av_log(codec, AV_LOG_WARNING, "aac samplerate index out of bounds\n");
return;
}
*sample_rate = aac_sample_rates[sri];
// if sbr, get output sample rate as well
if (codec->extradata_size == 5) {
sri = (codec->extradata[4] >> 3) & 0xF;
if (sri > 12) {
av_log(codec, AV_LOG_WARNING, "aac output samplerate index out of bounds\n");
return;
}
*output_sample_rate = aac_sample_rates[sri];
}
}
static int mkv_write_tracks(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
@ -361,6 +392,11 @@ static int mkv_write_tracks(AVFormatContext *s)
offset_t subinfo, track;
int native_id = 0;
int bit_depth = av_get_bits_per_sample(codec->codec_id);
int sample_rate = codec->sample_rate;
int output_sample_rate = 0;
if (codec->codec_id == CODEC_ID_AAC)
get_aac_sample_rates(codec, &sample_rate, &output_sample_rate);
track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
@ -400,7 +436,6 @@ static int mkv_write_tracks(AVFormatContext *s)
codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
// XXX: codec private isn't a master; is there a better way to re-use put_bmp_header?
bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
put_bmp_header(pb, codec, codec_bmp_tags, 0);
end_ebml_master(pb, bmp_header);
@ -432,8 +467,9 @@ static int mkv_write_tracks(AVFormatContext *s)
}
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO);
put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, codec->sample_rate);
// XXX: output sample freq (for sbr)
put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
if (output_sample_rate)
put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
if (bit_depth)
put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
end_ebml_master(pb, subinfo);