--- /dev/null
+diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
+index cab43f4..8688616 100644
+--- a/libavformat/matroskaenc.c
++++ b/libavformat/matroskaenc.c
+@@ -769,6 +769,8 @@ static int mkv_write_track(AVFormatContext *s, MatroskaMuxContext *mkv,
+ // if we need to clear it.
+ if (!(st->disposition & AV_DISPOSITION_DEFAULT))
+ put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGDEFAULT, !!(st->disposition & AV_DISPOSITION_DEFAULT));
++ if (st->disposition & AV_DISPOSITION_FORCED)
++ put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGFORCED, !!(st->disposition & AV_DISPOSITION_FORCED));
+
+ if (codec->codec_type == AVMEDIA_TYPE_AUDIO && codec->initial_padding) {
+ mkv->tracks[i].ts_offset = av_rescale_q(codec->initial_padding,
if ( ii == subtitle_default )
{
- track->st->disposition |= AV_DISPOSITION_DEFAULT;
+ track->st->disposition |= AV_DISPOSITION_DEFAULT |
+ AV_DISPOSITION_FORCED;
}
lang = lookup_lang_code(job->mux, subtitle->iso639_2 );