diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 07a4bb380a3b88ae8ddeedabed77800939597049..131a7498afe69a0d565f141e1f792d5ed82a1e11 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -574,7 +574,10 @@ static int mkv_write_tracks(AVFormatContext *s)
         switch (codec->codec_type) {
             case AVMEDIA_TYPE_VIDEO:
                 put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
-                put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, av_q2d(codec->time_base)*1E9);
+                if(st->avg_frame_rate.num && st->avg_frame_rate.den && 1.0/av_q2d(st->avg_frame_rate) > av_q2d(codec->time_base))
+                    put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, 1E9/av_q2d(st->avg_frame_rate));
+                else
+                    put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, av_q2d(codec->time_base)*1E9);
 
                 if (!native_id &&
                       ff_codec_get_tag(codec_movvideo_tags, codec->codec_id) &&