avformat/utils: check for malloc failure

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit a66893ac94)

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

libavformat/utils.c

@@ -3610,6 +3610,11 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
     st->info->last_dts = AV_NOPTS_VALUE;
 
     st->codec = avcodec_alloc_context3(c);
+    if (!st->codec) {
+        av_free(st->info);
+        av_free(st);
+        return NULL;
+    }
     if (s->iformat) {
         /* no default bitrate if decoding */
         st->codec->bit_rate = 0;