Merge commit 'ce67f442'

* commit 'ce67f442':
  lavf: Avoid setting avg_frame_rate if delta_dts is negative

Conflicts:
	libavformat/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/utils.c

@@ -2978,7 +2978,8 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
                 double best_error = 0.01;
 
                 if (st->info->codec_info_duration        >= INT64_MAX / st->time_base.num / 2||
-                    st->info->codec_info_duration_fields >= INT64_MAX / st->time_base.den)
+                    st->info->codec_info_duration_fields >= INT64_MAX / st->time_base.den ||
+                    st->info->codec_info_duration        < 0)
                     continue;
                 av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
                           st->info->codec_info_duration_fields*(int64_t)st->time_base.den,