From d88d0b6db6bd77269e3c2d3b4894c072f3860671 Mon Sep 17 00:00:00 2001
From: Carl Eugen Hoyos <cehoyos@ag.or.at>
Date: Sun, 27 Jan 2013 23:24:52 +0100
Subject: [PATCH] Write forced track flag to matroska files.

Based on a patch by Daniel Pielmeier, daniel pielmeier gmail
Fixes a part of ticket #1815.
---
 libavformat/matroskaenc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index a34f485293..c167c015fe 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -572,6 +572,8 @@ static int mkv_write_tracks(AVFormatContext *s)
 
         if (st->disposition)
             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, 1);
 
         // look for a codec ID string specific to mkv to use,
         // if none are found, use AVI codes