avformat/matroskadec: Check subtitle stream before dereferencing

Unrecognized streams are not allocated
Fixes: flicker-1.color1.vp91447030769.08.webm

Found-by: Chris Cunningham <chcunningham@google.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2015-11-17 18:19:01 +01:00
parent f6e5b17abb
commit a5034b324c

View File

@ -3076,6 +3076,7 @@ static int matroska_read_seek(AVFormatContext *s, int stream_index,
tracks[i].audio.buf_timecode = AV_NOPTS_VALUE;
tracks[i].end_timecode = 0;
if (tracks[i].type == MATROSKA_TRACK_TYPE_SUBTITLE &&
tracks[i].stream &&
tracks[i].stream->discard != AVDISCARD_ALL) {
index_sub = av_index_search_timestamp(
tracks[i].stream, st->index_entries[index].timestamp,