Merge commit 'e4eb13ca77624401ea7cef1ed6ad8e2d13fd2063'

Merged-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

libavformat/flvdec.c

@@ -989,6 +989,7 @@ skip:
 retry_duration:
         avio_seek(s->pb, fsize - 4, SEEK_SET);
         size = avio_rb32(s->pb);
+        if (size > 0 && size < fsize) {
             // Seek to the start of the last FLV tag at position (fsize - 4 - size)
             // but skip the byte indicating the type.
             avio_seek(s->pb, fsize - 3 - size, SEEK_SET);
@@ -1002,6 +1003,7 @@ retry_duration:
                     goto retry_duration;
                 }
             }
+        }
 
         avio_seek(s->pb, pos, SEEK_SET);
         flv->searched_for_end = 1;