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avcodec: add av_get_audio_frame_duration() function.

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This is a utility function for the user to get the frame duration based on
the codec id, frame size in bytes, and various AVCodecContext parameters.
pull/3/merge
Justin Ruggles 13 years ago
parent 6699d07480
commit 9524cf79df
4 changed files with 157 additions and 1 deletions
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  1. 4
      doc/APIchanges
  2. 10
      libavcodec/avcodec.h
  3. 142
      libavcodec/utils.c
  4. 2
      libavcodec/version.h

4
doc/APIchanges
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@ -12,6 +12,10 @@ libavutil: 2011-04-18
API changes, most recent first:
2012-xx-xx - lavc 54.8.0
xxxxxxx Add av_get_exact_bits_per_sample()
xxxxxxx Add av_get_audio_frame_duration()
2012-03-xx - xxxxxxx - lavc 54.7.0 - avcodec.h
Add av_codec_is_encoder/decoder().

10
libavcodec/avcodec.h
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@ -3942,6 +3942,16 @@ int av_get_bits_per_sample(enum CodecID codec_id);
*/
int av_get_exact_bits_per_sample(enum CodecID codec_id);
/**
* Return audio frame duration.
*
* @param avctx codec context
* @param frame_bytes size of the frame, or 0 if unknown
* @return frame duration, in samples, if known. 0 if not able to
* determine.
*/
int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);
/* frame parsing */
typedef struct AVCodecParserContext {
void *priv_data;

142
libavcodec/utils.c
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@ -1742,6 +1742,148 @@ int av_get_bits_per_sample(enum CodecID codec_id)
}
}
int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes)
{
int id, sr, ch, ba, tag, bps;
id = avctx->codec_id;
sr = avctx->sample_rate;
ch = avctx->channels;
ba = avctx->block_align;
tag = avctx->codec_tag;
bps = av_get_exact_bits_per_sample(avctx->codec_id);
/* codecs with an exact constant bits per sample */
if (bps > 0 && ch > 0 && frame_bytes > 0)
return (frame_bytes * 8) / (bps * ch);
bps = avctx->bits_per_coded_sample;
/* codecs with a fixed packet duration */
switch (id) {
case CODEC_ID_ADPCM_ADX: return 32;
case CODEC_ID_ADPCM_IMA_QT: return 64;
case CODEC_ID_ADPCM_EA_XAS: return 128;
case CODEC_ID_AMR_NB:
case CODEC_ID_GSM:
case CODEC_ID_QCELP:
case CODEC_ID_RA_144:
case CODEC_ID_RA_288: return 160;
case CODEC_ID_IMC: return 256;
case CODEC_ID_AMR_WB:
case CODEC_ID_GSM_MS: return 320;
case CODEC_ID_MP1: return 384;
case CODEC_ID_ATRAC1: return 512;
case CODEC_ID_ATRAC3: return 1024;
case CODEC_ID_MP2:
case CODEC_ID_MUSEPACK7: return 1152;
case CODEC_ID_AC3: return 1536;
}
if (sr > 0) {
/* calc from sample rate */
if (id == CODEC_ID_TTA)
return 256 * sr / 245;
if (ch > 0) {
/* calc from sample rate and channels */
if (id == CODEC_ID_BINKAUDIO_DCT)
return (480 << (sr / 22050)) / ch;
}
}
if (ba > 0) {
/* calc from block_align */
if (id == CODEC_ID_SIPR) {
switch (ba) {
case 20: return 160;
case 19: return 144;
case 29: return 288;
case 37: return 480;
}
}
}
if (frame_bytes > 0) {
/* calc from frame_bytes only */
if (id == CODEC_ID_TRUESPEECH)
return 240 * (frame_bytes / 32);
if (id == CODEC_ID_NELLYMOSER)
return 256 * (frame_bytes / 64);
if (bps > 0) {
/* calc from frame_bytes and bits_per_coded_sample */
if (id == CODEC_ID_ADPCM_G726)
return frame_bytes * 8 / bps;
}
if (ch > 0) {
/* calc from frame_bytes and channels */
switch (id) {
case CODEC_ID_ADPCM_4XM:
case CODEC_ID_ADPCM_IMA_ISS:
return (frame_bytes - 4 * ch) * 2 / ch;
case CODEC_ID_ADPCM_IMA_SMJPEG:
return (frame_bytes - 4) * 2 / ch;
case CODEC_ID_ADPCM_IMA_AMV:
return (frame_bytes - 8) * 2 / ch;
case CODEC_ID_ADPCM_XA:
return (frame_bytes / 128) * 224 / ch;
case CODEC_ID_INTERPLAY_DPCM:
return (frame_bytes - 6 - ch) / ch;
case CODEC_ID_ROQ_DPCM:
return (frame_bytes - 8) / ch;
case CODEC_ID_XAN_DPCM:
return (frame_bytes - 2 * ch) / ch;
case CODEC_ID_MACE3:
return 3 * frame_bytes / ch;
case CODEC_ID_MACE6:
return 6 * frame_bytes / ch;
case CODEC_ID_PCM_LXF:
return 2 * (frame_bytes / (5 * ch));
}
if (tag) {
/* calc from frame_bytes, channels, and codec_tag */
if (id == CODEC_ID_SOL_DPCM) {
if (tag == 3)
return frame_bytes / ch;
else
return frame_bytes * 2 / ch;
}
}
if (ba > 0) {
/* calc from frame_bytes, channels, and block_align */
int blocks = frame_bytes / ba;
switch (avctx->codec_id) {
case CODEC_ID_ADPCM_IMA_WAV:
return blocks * (1 + (ba - 4 * ch) / (4 * ch) * 8);
case CODEC_ID_ADPCM_IMA_DK3:
return blocks * (((ba - 16) * 8 / 3) / ch);
case CODEC_ID_ADPCM_IMA_DK4:
return blocks * (1 + (ba - 4 * ch) * 2 / ch);
case CODEC_ID_ADPCM_MS:
return blocks * (2 + (ba - 7 * ch) * 2 / ch);
}
}
if (bps > 0) {
/* calc from frame_bytes, channels, and bits_per_coded_sample */
switch (avctx->codec_id) {
case CODEC_ID_PCM_DVD:
return 2 * (frame_bytes / ((bps * 2 / 8) * ch));
case CODEC_ID_PCM_BLURAY:
return frame_bytes / ((FFALIGN(ch, 2) * bps) / 8);
case CODEC_ID_S302M:
return 2 * (frame_bytes / ((bps + 4) / 4)) / ch;
}
}
}
}
return 0;
}
#if !HAVE_THREADS
int ff_thread_init(AVCodecContext *s){
return -1;

2
libavcodec/version.h
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@ -21,7 +21,7 @@
#define AVCODEC_VERSION_H
#define LIBAVCODEC_VERSION_MAJOR 54
#define LIBAVCODEC_VERSION_MINOR 7
#define LIBAVCODEC_VERSION_MINOR 8
#define LIBAVCODEC_VERSION_MICRO 0
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \

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