avformat_free_context: allow NULL as argument

Fixes CID703682
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

diff --git a/libavformat/utils.c b/libavformat/utils.c
index be1be00..f27104e 100644 (file)
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -3018,6 +3018,9 @@ void avformat_free_context(AVFormatContext *s)
 {
     int i;
 
+    if (!s)
+        return;
+
     av_opt_free(s);
     if (s->iformat && s->iformat->priv_class && s->priv_data)
         av_opt_free(s->priv_data);