| Message ID | 20201105231110.7772-1-michael@niedermayer.cc |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [FFmpeg-devel,1/7,RFC] Revert "avcodec/adpcm_swf: support decoding multiple fixed-sized blocks at once" | expand |
| Context | Check | Description |
|---|---|---|
| andriy/x86_make | success | Make finished |
| andriy/x86_make_fate | success | Make fate finished |
On 6/11/20 9:11 am, Michael Niedermayer wrote: > The reverted code split at block_align boundaries, but there was already code > which splits at a hardcoded 4096 sample boundary. > > reverting this seemed like the easiest fix but this is a RFC in case another solution > is preferred > This breaks playback when adpcm_swf is used in WAVs. block_align needs to be respected otherwise everything is garbled. When coming from a SWF file, block_align isn't set so it reverts to the legacy behaviour. See https://trac.ffmpeg.org/ticket/5829
On 6/11/20 11:51 am, Zane van Iperen wrote: > > > On 6/11/20 9:11 am, Michael Niedermayer wrote: >> The reverted code split at block_align boundaries, but there was already code >> which splits at a hardcoded 4096 sample boundary. >> >> reverting this seemed like the easiest fix but this is a RFC in case another solution >> is preferred >> > > This breaks playback when adpcm_swf is used in WAVs. block_align needs to be respected > otherwise everything is garbled. > When coming from a SWF file, block_align isn't set so it reverts to the legacy behaviour. > > See https://trac.ffmpeg.org/ticket/5829 > > Never mind, this behaviour is wrong. Turns out the encoder was producing invalid frames and this simply covered-up the issue. Revert away! I'll send out a fix for the encoder soon.
diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c index 701b125c47..d018c1f91b 100644 --- a/libavcodec/adpcm.c +++ b/libavcodec/adpcm.c @@ -880,7 +880,7 @@ static int get_nb_samples(AVCodecContext *avctx, GetByteContext *gb, } case AV_CODEC_ID_ADPCM_SWF: { - int buf_bits = (avctx->block_align ? avctx->block_align : buf_size) * 8 - 2; + int buf_bits = buf_size * 8 - 2; int nbits = (bytestream2_get_byte(gb) >> 6) + 2; int block_hdr_size = 22 * ch; int block_size = block_hdr_size + nbits * ch * 4095; @@ -889,9 +889,6 @@ static int get_nb_samples(AVCodecContext *avctx, GetByteContext *gb, nb_samples = nblocks * 4096; if (bits_left >= block_hdr_size) nb_samples += 1 + (bits_left - block_hdr_size) / (nbits * ch); - - if (avctx->block_align) - nb_samples *= buf_size / avctx->block_align; break; } case AV_CODEC_ID_ADPCM_THP: @@ -1770,17 +1767,9 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data, } break; case AV_CODEC_ID_ADPCM_SWF: - { - const int nb_blocks = avctx->block_align ? avpkt->size / avctx->block_align : 1; - const int block_size = avctx->block_align ? avctx->block_align : avpkt->size; - - for (int block = 0; block < nb_blocks; block++) { - adpcm_swf_decode(avctx, buf + block * block_size, block_size, samples); - samples += nb_samples / nb_blocks; - } + adpcm_swf_decode(avctx, buf, buf_size, samples); bytestream2_seek(&gb, 0, SEEK_END); break; - } case AV_CODEC_ID_ADPCM_YAMAHA: for (n = nb_samples >> (1 - st); n > 0; n--) { int v = bytestream2_get_byteu(&gb);