Merge commit 'df33a58e'

* commit 'df33a58e':
  lavf: avoid integer overflow when estimating bitrate
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/utils.c

@@ -2222,9 +2222,14 @@ static void estimate_timings_from_bit_rate(AVFormatContext *ic)
         int bit_rate = 0;
         for(i=0;i<ic->nb_streams;i++) {
             st = ic->streams[i];
-            if (st->codec->bit_rate > 0)
+            if (st->codec->bit_rate > 0) {
+                if (INT_MAX - st->codec->bit_rate > bit_rate) {
+                    bit_rate = 0;
+                    break;
+                }
                 bit_rate += st->codec->bit_rate;
             }
+        }
         ic->bit_rate = bit_rate;
     }