vmdaudio: output audio samples for standalone silent blocks.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
(cherry picked from commit 9b73f78600)

libavcodec/vmdav.c

@@ -534,7 +534,7 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx,
         *data_size += vmdaudio_loadsound(s, output_samples, p + 4, 0, buf_size - 20);
     } else if (buf[6] == 3) {
         /* silent chunk */
-        *data_size = vmdaudio_loadsound(s, output_samples, p, 1, 0);
+        *data_size = vmdaudio_loadsound(s, output_samples, p, 1, s->block_align);
     }
 
     return buf_size;

tests/ref/fate/sierra-vmd

@@ -301,3 +301,32 @@
 1, 1890000, 4410, 0x5d2b15f4
 1, 1899000, 4410, 0x48764b7c
 1, 1908000, 4410, 0x1294e119
+1, 1917000, 4410, 0x00000000
+1, 1926000, 4410, 0x00000000
+1, 1935000, 4410, 0x00000000
+1, 1944000, 4410, 0x00000000
+1, 1953000, 4410, 0x00000000
+1, 1962000, 4410, 0x00000000
+1, 1971000, 4410, 0x00000000
+1, 1980000, 4410, 0x00000000
+1, 1989000, 4410, 0x00000000
+1, 1998000, 4410, 0x00000000
+1, 2007000, 4410, 0x00000000
+1, 2016000, 4410, 0x00000000
+1, 2025000, 4410, 0x00000000
+1, 2034000, 4410, 0x00000000
+1, 2043000, 4410, 0x00000000
+1, 2052000, 4410, 0x00000000
+1, 2061000, 4410, 0x00000000
+1, 2070000, 4410, 0x00000000
+1, 2079000, 4410, 0x00000000
+1, 2088000, 4410, 0x00000000
+1, 2097000, 4410, 0x00000000
+1, 2106000, 4410, 0x00000000
+1, 2115000, 4410, 0x00000000
+1, 2124000, 4410, 0x00000000
+1, 2133000, 4410, 0x00000000
+1, 2142000, 4410, 0x00000000
+1, 2151000, 4410, 0x00000000
+1, 2160000, 4410, 0x00000000
+1, 2169000, 4410, 0x00000000