diff --git a/ffmpeg.c b/ffmpeg.c
index beb44ce0629cdd6e98347d678ef72ef2765fa5bc..fc3264aae48212548c10273c4b0cff2b6d73a115 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -3116,6 +3116,8 @@ static void opt_input_file(const char *filename)
             break;
         case CODEC_TYPE_SUBTITLE:
             break;
+        case CODEC_TYPE_UNKNOWN:
+            break;
         default:
             av_abort();
         }
@@ -3163,6 +3165,7 @@ static void check_audio_video_inputs(int *has_video_ptr, int *has_audio_ptr)
                 has_video = 1;
                 break;
             case CODEC_TYPE_DATA:
+            case CODEC_TYPE_UNKNOWN:
             case CODEC_TYPE_SUBTITLE:
                 break;
             default:
diff --git a/libavformat/asf.c b/libavformat/asf.c
index 19265ac6a61de289462a80b69b3202b9c5eeb685..435d8256d8a281a03b463046b1c27e36d7327470 100644
--- a/libavformat/asf.c
+++ b/libavformat/asf.c
@@ -51,6 +51,7 @@ static void print_guid(const GUID *g)
     else PRINT_IF_GUID(g, audio_conceal_none);
     else PRINT_IF_GUID(g, video_stream);
     else PRINT_IF_GUID(g, video_conceal_none);
+    else PRINT_IF_GUID(g, command_stream);
     else PRINT_IF_GUID(g, comment_header);
     else PRINT_IF_GUID(g, codec_comment_header);
     else PRINT_IF_GUID(g, codec_comment1_header);
@@ -204,6 +205,8 @@ static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)
                 type = CODEC_TYPE_AUDIO;
             } else if (!memcmp(&g, &video_stream, sizeof(GUID))) {
                 type = CODEC_TYPE_VIDEO;
+            } else if (!memcmp(&g, &command_stream, sizeof(GUID))) {
+                type = CODEC_TYPE_UNKNOWN;
             } else {
                 goto fail;
             }
diff --git a/libavformat/asf.h b/libavformat/asf.h
index 5a13c85b7602e251cc9a426aef472b2a2c489082..2cf976fa2ced3dfaa6bdb694e3740c1fe8091d0b 100644
--- a/libavformat/asf.h
+++ b/libavformat/asf.h
@@ -165,6 +165,9 @@ static const GUID video_conceal_none = {
     0x20FB5700, 0x5B55, 0x11CF, { 0xA8, 0xFD, 0x00, 0x80, 0x5F, 0x5C, 0x44, 0x2B },
 };
 
+static const GUID command_stream = {
+    0x59DACFC0, 0x59E6, 0x11D0, { 0xA3, 0xAC, 0x00, 0xA0, 0xC9, 0x03, 0x48, 0xF6 },
+};
 
 static const GUID comment_header = {
     0x75b22633, 0x668e, 0x11cf, { 0xa6, 0xd9, 0x00, 0xaa, 0x00, 0x62, 0xce, 0x6c },