Merge commit 'f128b8e19ac7f702adae899ab91cc1e80f238761'

* commit 'f128b8e19ac7f702adae899ab91cc1e80f238761':
  mov: detect cover art pictures by content

Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

libavformat/mov.c

@@ -194,6 +194,14 @@ static int mov_read_covr(MOVContext *c, AVIOContext *pb, int type, int len)
     if (ret < 0)
         return ret;
 
+    if (pkt.size >= 8 && id != AV_CODEC_ID_BMP) {
+        if (AV_RB64(pkt.data) == 0x89504e470d0a1a0a) {
+            id = AV_CODEC_ID_PNG;
+        } else {
+            id = AV_CODEC_ID_MJPEG;
+        }
+    }
+
     st->disposition              |= AV_DISPOSITION_ATTACHED_PIC;
 
     st->attached_pic              = pkt;