[FFmpeg-devel] [PATCH] dashenc: check pts to prevent division by zero error
Alfred E. Heggestad
alfred.heggestad at gmail.com
Thu Jan 30 11:58:01 EET 2020
this usecase will cause a division by zero trap:
1. dashenc has received one frame
2. os->max_pts and os->start_pts have same value
3. delta between max_pts and start_pts is 0
4. av_rescale_q(0, x, y) returns 0
5. this value is used as denominator in division
6. Bang! -> segfault
this fix checks that max_pts > start_pts.
the fix has been tested and works.
please review and suggest better fixes.
Signed-off-by: Alfred E. Heggestad <alfred.heggestad at gmail.com>
---
libavformat/dashenc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
index f555f208a7..3b651b9514 100644
--- a/libavformat/dashenc.c
+++ b/libavformat/dashenc.c
@@ -1883,7 +1883,7 @@ static int dash_flush(AVFormatContext *s, int
final, int stream)
st->time_base,
AV_TIME_BASE_Q));
- if (!os->muxer_overhead)
+ if (!os->muxer_overhead && os->max_pts > os->start_pts)
os->muxer_overhead = ((int64_t) (range_length -
os->total_pkt_size) *
8 * AV_TIME_BASE) /
av_rescale_q(os->max_pts - os->start_pts,
--
2.20.1 (Apple Git-117)
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