[FFmpeg-cvslog] avformat/matroskadec: Fix handling gigantic durations

[Andreas Rheinhardt]

ffmpeg | branch: release/4.3 | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Wed Sep  4 00:50:11 2019 +0200| [a2ab8babef6d6eabbd7ae5f5f36df9c069f7d94b] | committer: Andreas Rheinhardt

avformat/matroskadec: Fix handling gigantic durations

matroska_parse_block currently asserts that the duration is not equal to
AV_NOPTS_VALUE, but there is nothing that actually guarantees this. It
is easy to create (spec-compliant) files which run into this assert;
so replace it and instead cap the duration to INT64_MAX, as the duration
field of an AVPacket is an int64_t.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
(cherry picked from commit 3714d452b894821591a2fbafdd1b8ef15abe4be6)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a2ab8babef6d6eabbd7ae5f5f36df9c069f7d94b
---

 libavformat/matroskadec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index b1da40983f..1846b1f93c 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -3568,7 +3568,8 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, AVBufferRef *buf
 
     if (st->discard >= AVDISCARD_ALL)
         return res;
-    av_assert1(block_duration != AV_NOPTS_VALUE);
+    if (block_duration > INT64_MAX)
+        block_duration = INT64_MAX;
 
     block_time = sign_extend(AV_RB16(data), 16);
     data      += 2;