[FFmpeg-cvslog] avformat/dxa: Use av_rescale() for duration computation

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Wed Sep  2 23:13:00 2020 +0200| [c313089fbe1df71b5406dd9d7e4d36361051c620] | committer: Michael Niedermayer

avformat/dxa: Use av_rescale() for duration computation

Fixes: signed integer overflow: 8224000000 * 1629552639 cannot be represented in type 'long'
Fixes: 24908/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-4658478506049536

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c313089fbe1df71b5406dd9d7e4d36361051c620
---

 libavformat/dxa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/dxa.c b/libavformat/dxa.c
index 27fa6afb6a..909c5ba2ba 100644
--- a/libavformat/dxa.c
+++ b/libavformat/dxa.c
@@ -143,7 +143,7 @@ static int dxa_read_header(AVFormatContext *s)
     c->readvid = !c->has_sound;
     c->vidpos  = avio_tell(pb);
     s->start_time = 0;
-    s->duration = (int64_t)c->frames * AV_TIME_BASE * num / den;
+    s->duration = av_rescale(c->frames, AV_TIME_BASE * (int64_t)num, den);
     av_log(s, AV_LOG_DEBUG, "%d frame(s)\n",c->frames);
 
     return 0;