From 3829a02738c16cfc84f41fd4b55a34c03386a65b Mon Sep 17 00:00:00 2001
From: Rodger Combs <rodger.combs@gmail.com>
Date: Mon, 5 Sep 2016 21:43:18 -0500
Subject: [PATCH] lavf/matroskaenc: skip writing "duration" tags

---
 libavformat/matroskaenc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index decb66de75..7deccaaa74 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -1314,6 +1314,7 @@ static int mkv_check_tag_name(const char *name, unsigned int elementid)
            av_strcasecmp(name, "stereo_mode") &&
            av_strcasecmp(name, "creation_time") &&
            av_strcasecmp(name, "encoding_tool") &&
+           av_strcasecmp(name, "duration") &&
            (elementid != MATROSKA_ID_TAGTARGETS_TRACKUID ||
             av_strcasecmp(name, "language"));
 }