[FFmpeg-cvslog] avcodec/adpcm_swf: support decoding multiple fixed-sized blocks at once

[Zane van Iperen]

ffmpeg | branch: master | Zane van Iperen <zane at zanevaniperen.com> | Fri Oct 16 13:14:25 2020 +1000| [e9dd73d30d09043446ac6dd7b8ad31e557873852] | committer: Zane van Iperen

avcodec/adpcm_swf: support decoding multiple fixed-sized blocks at once

For incoming packets from WAV.

Signed-off-by: Zane van Iperen <zane at zanevaniperen.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e9dd73d30d09043446ac6dd7b8ad31e557873852
---

 libavcodec/adpcm.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index d018c1f91b..701b125c47 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       = buf_size * 8 - 2;
+        int buf_bits       = (avctx->block_align ? avctx->block_align : 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;
@@ -889,6 +889,9 @@ 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:
@@ -1767,9 +1770,17 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
         }
         break;
     case AV_CODEC_ID_ADPCM_SWF:
-        adpcm_swf_decode(avctx, buf, buf_size, samples);
+    {
+        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;
+        }
         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);