nellymoserdec: Allow using unusual input block sizes

Originally committed as revision 23602 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/nellymoserdec.c

@@ -178,9 +178,13 @@ static int decode_tag(AVCodecContext * avctx,
         case 512:   // 44100Hz
             blocks = 8; break;
         default:
+            if (buf_size % 64) {
             av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size);
             return buf_size;
             }
+            blocks = buf_size / 64;
+            break;
+    }
 
     for (i=0 ; i<blocks ; i++) {
         nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);