[FFmpeg-cvslog] avformat/format: Check for av_guess_format() failure

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sat Aug  2 04:16:02 2014 +0200| [98e42a249e7891d295228ff19892450ba1f09092] | committer: Michael Niedermayer

avformat/format: Check for av_guess_format() failure

Fixes null pointer dereference
Fixes Ticket3812

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=98e42a249e7891d295228ff19892450ba1f09092
---

 libavformat/format.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavformat/format.c b/libavformat/format.c
index 238a13a..1c25d6b 100644
--- a/libavformat/format.c
+++ b/libavformat/format.c
@@ -145,7 +145,9 @@ enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
                               enum AVMediaType type)
 {
     if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
-        fmt = av_guess_format(NULL, filename, NULL);
+        AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
+        if (fmt2)
+            fmt = fmt2;
     }
 
     if (type == AVMEDIA_TYPE_VIDEO) {