mm: set channel layout

libavformat/mm.c

@@ -31,6 +31,7 @@
  *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
  */
 
+#include "libavutil/channel_layout.h"
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"
 #include "internal.h"
@@ -124,6 +125,7 @@ static int read_header(AVFormatContext *s)
         st->codec->codec_tag = 0; /* no fourcc */
         st->codec->codec_id = AV_CODEC_ID_PCM_U8;
         st->codec->channels = 1;
+        st->codec->channel_layout = AV_CH_LAYOUT_MONO;
         st->codec->sample_rate = 8000;
         avpriv_set_pts_info(st, 64, 1, 8000); /* 8000 hz */
     }