MOV: Fix writing \251wrt metadata (r20453 only fixed the demuxer)

Originally committed as revision 20585 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/movenc.c

@@ -1370,7 +1370,7 @@ static int mov_write_ilst_tag(ByteIOContext *pb, MOVMuxContext *mov,
     put_tag(pb, "ilst");
     mov_write_string_metadata(s, pb, "\251nam", "title"    , 1);
     mov_write_string_metadata(s, pb, "\251ART", "author"   , 1);
-    mov_write_string_metadata(s, pb, "\251wrt", "author"   , 1);
+    mov_write_string_metadata(s, pb, "\251wrt", "composer" , 1);
     mov_write_string_metadata(s, pb, "\251alb", "album"    , 1);
     mov_write_string_metadata(s, pb, "\251day", "year"     , 1);
     mov_write_string_tag(pb, "\251too", LIBAVFORMAT_IDENT, 0, 1);