[FFmpeg-cvslog] oggparseskeleton: Check the overall start time before using it.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Tue Jan  8 02:52:15 2013 +0100| [1a088f61e1b8d620c313c47d861a1a4b29fd7156] | committer: Michael Niedermayer

oggparseskeleton: Check the overall start time before using it.

Fixes division by zero

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1a088f61e1b8d620c313c47d861a1a4b29fd7156
---

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

diff --git a/libavformat/oggparseskeleton.c b/libavformat/oggparseskeleton.c
index f9ad701..b6959a6 100644
--- a/libavformat/oggparseskeleton.c
+++ b/libavformat/oggparseskeleton.c
@@ -61,7 +61,7 @@ static int skeleton_header(AVFormatContext *s, int idx)
         start_num = AV_RL64(buf+12);
         start_den = AV_RL64(buf+20);
 
-        if (start_den) {
+        if (start_den > 0 && start_num > 0) {
             int base_den;
             av_reduce(&start_time, &base_den, start_num, start_den, INT_MAX);
             avpriv_set_pts_info(st, 64, 1, base_den);