Fix MS ADPCM de- and encoding: first and second sample are swapped.

Noticeable better decoding of e.g. http://samples.mplayerhq.hu/A-codecs/msadpcm-stereo/dance-b5th.asf

Originally committed as revision 14201 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/adpcm.c

@@ -603,16 +603,16 @@ static int adpcm_encode_frame(AVCodecContext *avctx,
 
             bytestream_put_le16(&dst, c->status[i].idelta);
         }
+        for(i=0; i<avctx->channels; i++){
+            c->status[i].sample2= *samples++;
+        }
         for(i=0; i<avctx->channels; i++){
             c->status[i].sample1= *samples++;
 
             bytestream_put_le16(&dst, c->status[i].sample1);
         }
-        for(i=0; i<avctx->channels; i++){
-            c->status[i].sample2= *samples++;
-
+        for(i=0; i<avctx->channels; i++)
             bytestream_put_le16(&dst, c->status[i].sample2);
-        }
 
         if(avctx->trellis > 0) {
             int n = avctx->block_align - 7*avctx->channels;
@@ -1050,10 +1050,10 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
         if (st) c->status[1].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
         if (st) src+=2;
 
-        *samples++ = c->status[0].sample1;
-        if (st) *samples++ = c->status[1].sample1;
         *samples++ = c->status[0].sample2;
         if (st) *samples++ = c->status[1].sample2;
+        *samples++ = c->status[0].sample1;
+        if (st) *samples++ = c->status[1].sample1;
         for(;n>0;n--) {
             *samples++ = adpcm_ms_expand_nibble(&c->status[0 ], src[0] >> 4  );
             *samples++ = adpcm_ms_expand_nibble(&c->status[st], src[0] & 0x0F);

tests/ffmpeg.regression.ref

@@ -181,10 +181,10 @@ efdae2746040dbc27be402b149556f1e *./tests/data/a-adpcm_qt.aiff
 281184 ./tests/data/a-adpcm_qt.aiff
 5a2084ad27674d5cf3bc2945061e7910 *./tests/data/adpcm_ima_qt.vsynth.out.wav
 stddev:915.35 PSNR:37.09 bytes:1056768
-628d4789cf9ee16a756ac54b7fd8650d *./tests/data/a-adpcm_ms.wav
+88a0c48c9bc6d50a84c408151c6a3d64 *./tests/data/a-adpcm_ms.wav
 267320 ./tests/data/a-adpcm_ms.wav
-91a84bb4f319a3a0bf0c0441b3d3a529 *./tests/data/adpcm_ms.vsynth.out.wav
-stddev:1050.18 PSNR:35.89 bytes:1054720
+d5f98f5136040be42232a34df92d61f2 *./tests/data/adpcm_ms.vsynth.out.wav
+stddev:1051.84 PSNR:35.88 bytes:1054720
 ab11d9151644cbff27827b7e89f37aa9 *./tests/data/a-adpcm_yam.wav
 264248 ./tests/data/a-adpcm_yam.wav
 e92cec8c07913ffb91ad2b11f79cdc00 *./tests/data/adpcm_yam.vsynth.out.wav

tests/rotozoom.regression.ref

@@ -181,10 +181,10 @@ efdae2746040dbc27be402b149556f1e *./tests/data/a-adpcm_qt.aiff
 281184 ./tests/data/a-adpcm_qt.aiff
 5a2084ad27674d5cf3bc2945061e7910 *./tests/data/adpcm_ima_qt.rotozoom.out.wav
 stddev:915.35 PSNR:37.09 bytes:1056768
-628d4789cf9ee16a756ac54b7fd8650d *./tests/data/a-adpcm_ms.wav
+88a0c48c9bc6d50a84c408151c6a3d64 *./tests/data/a-adpcm_ms.wav
 267320 ./tests/data/a-adpcm_ms.wav
-91a84bb4f319a3a0bf0c0441b3d3a529 *./tests/data/adpcm_ms.rotozoom.out.wav
-stddev:1050.18 PSNR:35.89 bytes:1054720
+d5f98f5136040be42232a34df92d61f2 *./tests/data/adpcm_ms.rotozoom.out.wav
+stddev:1051.84 PSNR:35.88 bytes:1054720
 ab11d9151644cbff27827b7e89f37aa9 *./tests/data/a-adpcm_yam.wav
 264248 ./tests/data/a-adpcm_yam.wav
 e92cec8c07913ffb91ad2b11f79cdc00 *./tests/data/adpcm_yam.rotozoom.out.wav