fix \0xa9wrt metadata, to composer, fix issue #1501

Originally committed as revision 20453 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mov.c

@@ -106,8 +106,8 @@ static int mov_read_udta_string(MOVContext *c, ByteIOContext *pb, MOVAtom atom)
     switch (atom.type) {
     case MKTAG(0xa9,'n','a','m'): key = "title";     break;
     case MKTAG(0xa9,'a','u','t'):
-    case MKTAG(0xa9,'A','R','T'):
-    case MKTAG(0xa9,'w','r','t'): key = "author";    break;
+    case MKTAG(0xa9,'A','R','T'): key = "author";    break;
+    case MKTAG(0xa9,'w','r','t'): key = "composer";  break;
     case MKTAG(0xa9,'c','p','y'): key = "copyright"; break;
     case MKTAG(0xa9,'c','m','t'):
     case MKTAG(0xa9,'i','n','f'): key = "comment";   break;