[FFmpeg-cvslog] g726: use bits_per_coded_sample instead of bitrate to determine mode
Justin Ruggles
git at videolan.org
Thu Nov 3 02:23:05 CET 2011
ffmpeg | branch: master | Justin Ruggles <justin.ruggles at gmail.com> | Thu Oct 27 20:16:45 2011 -0400| [6ac34eed54f8e0298acb16636d0104c297e3d09f] | committer: Justin Ruggles
g726: use bits_per_coded_sample instead of bitrate to determine mode
This requires some workarounds in the WAV muxer and demuxer. We need to write
the correct bits_per_coded_sample and block_align in the muxer. In the
demuxer, we cannot rely on the bits_per_coded_sample value, so we use the bit
rate and sample rate to determine the value.
This avoids having the decoder rely on AVCodecContext.bit_rate, which is not
required to be set by the user for decoding according to our API.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6ac34eed54f8e0298acb16636d0104c297e3d09f
---
libavcodec/g726.c | 40 +++++++++++++++++++---------------------
libavformat/riff.c | 17 ++++++++++-------
2 files changed, 29 insertions(+), 28 deletions(-)
diff --git a/libavcodec/g726.c b/libavcodec/g726.c
index b150f58..3392811 100644
--- a/libavcodec/g726.c
+++ b/libavcodec/g726.c
@@ -301,29 +301,29 @@ static int16_t g726_encode(G726Context* c, int16_t sig)
static av_cold int g726_encode_init(AVCodecContext *avctx)
{
G726Context* c = avctx->priv_data;
- unsigned int index;
if (avctx->sample_rate <= 0) {
av_log(avctx, AV_LOG_ERROR, "Samplerate is invalid\n");
return -1;
}
- index = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate - 2;
-
- if (avctx->bit_rate % avctx->sample_rate) {
- av_log(avctx, AV_LOG_ERROR, "Bitrate - Samplerate combination is invalid\n");
- return -1;
- }
if(avctx->channels != 1){
av_log(avctx, AV_LOG_ERROR, "Only mono is supported\n");
return -1;
}
- if(index>3){
- av_log(avctx, AV_LOG_ERROR, "Unsupported number of bits %d\n", index+2);
- return -1;
+
+ if (avctx->bit_rate % avctx->sample_rate) {
+ av_log(avctx, AV_LOG_ERROR, "Bitrate - Samplerate combination is invalid\n");
+ return AVERROR(EINVAL);
+ }
+ c->code_size = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate;
+ if (c->code_size < 2 || c->code_size > 5) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid number of bits %d\n", c->code_size);
+ return AVERROR(EINVAL);
}
- g726_reset(c, index);
- c->code_size = index+2;
+ avctx->bits_per_coded_sample = c->code_size;
+
+ g726_reset(c, c->code_size - 2);
avctx->coded_frame = avcodec_alloc_frame();
if (!avctx->coded_frame)
@@ -332,7 +332,7 @@ static av_cold int g726_encode_init(AVCodecContext *avctx)
/* select a frame size that will end on a byte boundary and have a size of
approximately 1024 bytes */
- avctx->frame_size = ((int[]){ 4096, 2736, 2048, 1640 })[index];
+ avctx->frame_size = ((int[]){ 4096, 2736, 2048, 1640 })[c->code_size - 2];
return 0;
}
@@ -365,25 +365,23 @@ static int g726_encode_frame(AVCodecContext *avctx,
static av_cold int g726_decode_init(AVCodecContext *avctx)
{
G726Context* c = avctx->priv_data;
- unsigned int index;
if (avctx->sample_rate <= 0) {
av_log(avctx, AV_LOG_ERROR, "Samplerate is invalid\n");
return -1;
}
- index = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate - 2;
-
if(avctx->channels != 1){
av_log(avctx, AV_LOG_ERROR, "Only mono is supported\n");
return -1;
}
- if(index>3){
- av_log(avctx, AV_LOG_ERROR, "Unsupported number of bits %d\n", index+2);
- return -1;
+
+ c->code_size = avctx->bits_per_coded_sample;
+ if (c->code_size < 2 || c->code_size > 5) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid number of bits %d\n", c->code_size);
+ return AVERROR(EINVAL);
}
- g726_reset(c, index);
- c->code_size = index+2;
+ g726_reset(c, c->code_size - 2);
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
diff --git a/libavformat/riff.c b/libavformat/riff.c
index 0f4c079..8eed7ce 100644
--- a/libavformat/riff.c
+++ b/libavformat/riff.c
@@ -385,11 +385,13 @@ int ff_put_wav_header(AVIOContext *pb, AVCodecContext *enc)
avio_wl32(pb, enc->sample_rate);
if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3 || enc->codec_id == CODEC_ID_GSM_MS) {
bps = 0;
- } else if (enc->codec_id == CODEC_ID_ADPCM_G726) {
- bps = 4;
} else {
- if (!(bps = av_get_bits_per_sample(enc->codec_id)))
- bps = 16; // default to 16
+ if (!(bps = av_get_bits_per_sample(enc->codec_id))) {
+ if (enc->bits_per_coded_sample)
+ bps = enc->bits_per_coded_sample;
+ else
+ bps = 16; // default to 16
+ }
}
if(bps != enc->bits_per_coded_sample && enc->bits_per_coded_sample){
av_log(enc, AV_LOG_WARNING, "requested bits_per_coded_sample (%d) and actually stored (%d) differ\n", enc->bits_per_coded_sample, bps);
@@ -400,12 +402,10 @@ int ff_put_wav_header(AVIOContext *pb, AVCodecContext *enc)
//blkalign = 144 * enc->bit_rate/enc->sample_rate;
} else if (enc->codec_id == CODEC_ID_AC3) {
blkalign = 3840; //maximum bytes per frame
- } else if (enc->codec_id == CODEC_ID_ADPCM_G726) { //
- blkalign = 1;
} else if (enc->block_align != 0) { /* specified by the codec */
blkalign = enc->block_align;
} else
- blkalign = enc->channels*bps >> 3;
+ blkalign = bps * enc->channels / av_gcd(8, bps);
if (enc->codec_id == CODEC_ID_PCM_U8 ||
enc->codec_id == CODEC_ID_PCM_S24LE ||
enc->codec_id == CODEC_ID_PCM_S32LE ||
@@ -545,6 +545,9 @@ int ff_get_wav_header(AVIOContext *pb, AVCodecContext *codec, int size)
codec->channels = 0;
codec->sample_rate = 0;
}
+ /* override bits_per_coded_sample for G.726 */
+ if (codec->codec_id == CODEC_ID_ADPCM_G726)
+ codec->bits_per_coded_sample = codec->bit_rate / codec->sample_rate;
return 0;
}
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