@@ -147,6 +147,14 @@ const ff_asf_guid ff_asf_extended_stream_properties_object = {

     0xcb, 0xa5, 0xe6, 0x14, 0x72, 0xc6, 0x32, 0x43, 0x83, 0x99, 0xa9, 0x69, 0x52, 0x06, 0x5b, 0x5a

 };

+const ff_asf_guid ff_asf_group_mutual_exclusion_object = {

+    0x40, 0x5a, 0x46, 0xd1, 0x79, 0x5a, 0x38, 0x43, 0xb7, 0x1b, 0xe3, 0x6b, 0x8f, 0xd6, 0xc2, 0x49

+};

+

+const ff_asf_guid ff_asf_mutex_language = {

+    0x00, 0x2a, 0xe2, 0xd6, 0xda, 0x35, 0xd1, 0x11, 0x90, 0x34, 0x00, 0xa0, 0xc9, 0x03, 0x49, 0xbe

+};

+

 /* List of official tags at http://msdn.microsoft.com/en-us/library/dd743066(VS.85).aspx */

 const AVMetadataConv ff_asf_metadata_conv[] = {

     { "WM/AlbumArtist",          "album_artist"     },

@@ -100,6 +100,8 @@ extern const ff_asf_guid ff_asf_content_encryption;

 extern const ff_asf_guid ff_asf_ext_content_encryption;

 extern const ff_asf_guid ff_asf_digital_signature;

 extern const ff_asf_guid ff_asf_extended_stream_properties_object;

+extern const ff_asf_guid ff_asf_group_mutual_exclusion_object;

+extern const ff_asf_guid ff_asf_mutex_language;

 extern const AVMetadataConv ff_asf_metadata_conv[];

@@ -396,6 +396,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,

     int64_t header_offset, cur_pos, hpos;

     int bit_rate;

     int64_t duration;

+    int audio_language_counts[128] = { 0 };

     ff_metadata_conv(&s->metadata, ff_asf_metadata_conv, NULL);

@@ -444,6 +445,8 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,

                     asf->streams[n].stream_language_index = asf->nb_languages;

                     asf->nb_languages++;

                 }

+                if (enc->codec_type == AVMEDIA_TYPE_AUDIO)

+                    audio_language_counts[asf->streams[n].stream_language_index]++;

             }

         } else {

             asf->streams[n].stream_language_index = 128;

@@ -484,6 +487,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,

     if (asf->nb_languages) {

         int64_t hpos2;

         int i;

+        int nb_audio_languages = 0;

         hpos2 = put_header(pb, &ff_asf_language_guid);

         avio_wl16(pb, asf->nb_languages);

@@ -493,6 +497,25 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,

         }

         end_header(pb, hpos2);

+        for (i = 0; i < asf->nb_languages; i++)

+            if (audio_language_counts[i])

+                nb_audio_languages++;

+

+        if (nb_audio_languages > 1) {

+            hpos2 = put_header(pb, &ff_asf_group_mutual_exclusion_object);

+            ff_put_guid(pb, &ff_asf_mutex_language);

+            avio_wl16(pb, nb_audio_languages);

+            for (i = 0; i < asf->nb_languages; i++) {

+                if (audio_language_counts[i]) {

+                    avio_wl16(pb, audio_language_counts[i]);

+                    for (n = 0; n < s->nb_streams; n++)

+                        if (asf->streams[n].stream_language_index == i && s->streams[n]->codec->codec_type == AVMEDIA_TYPE_AUDIO)

+                            avio_wl16(pb, n + 1);

+                }

+            }

+            end_header(pb, hpos2);

+        }

+

         for (n = 0; n < s->nb_streams; n++) {

             int64_t es_pos;

             if (asf->streams[n].stream_language_index > 127)