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| author | Zane van Iperen <zane@zanevaniperen.com> | 2020-11-02 15:47:26 +1000 |
|---|---|---|
| committer | Zane van Iperen <zane@zanevaniperen.com> | 2020-11-09 14:58:37 +1000 |
| commit | 8903cb3c15344d90a6959cd5f416b74e4ef23dbc (patch) | |
| tree | 5124f208bc38796b1d798699288dfd36f766a7fd /libavcodec/adpcm.c | |
| parent | 50d3a751aab0bd7a831b12f8336c47c315a5f579 (diff) | |
| download | ffmpeg-8903cb3c15344d90a6959cd5f416b74e4ef23dbc.tar.gz | |
avcodec/adpcm_ima_amv: document header format
Signed-off-by: Zane van Iperen <zane@zanevaniperen.com>
Diffstat (limited to 'libavcodec/adpcm.c')
| -rw-r--r-- | libavcodec/adpcm.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c index 7762694e3e..01aced2e10 100644 --- a/libavcodec/adpcm.c +++ b/libavcodec/adpcm.c @@ -1690,6 +1690,16 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data, case AV_CODEC_ID_ADPCM_IMA_AMV: av_assert0(avctx->channels == 1); + /* + * Header format: + * int16_t predictor; + * uint8_t step_index; + * uint8_t reserved; + * uint32_t frame_size; + * + * Some implementations have step_index as 16-bits, but others + * only use the lower 8 and store garbage in the upper 8. + */ c->status[0].predictor = sign_extend(bytestream2_get_le16u(&gb), 16); c->status[0].step_index = bytestream2_get_byteu(&gb); bytestream2_skipu(&gb, 5); |