In mov muxer, write artist metadata tag

Originally committed as revision 25498 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/movenc.c

@@ -1610,6 +1610,7 @@ static int mov_write_udta_tag(ByteIOContext *pb, MOVMuxContext *mov,
             mov_write_3gp_udta_tag(pb_buf, s, "cprt", "copyright");
             mov_write_3gp_udta_tag(pb_buf, s, "yrrc", "date");
         } else if (mov->mode == MODE_MOV) { // the title field breaks gtkpod with mp4 and my suspicion is that stuff is not valid in mp4
+            mov_write_string_metadata(s, pb_buf, "\251ART", "artist"     , 0);
             mov_write_string_metadata(s, pb_buf, "\251nam", "title"      , 0);
             mov_write_string_metadata(s, pb_buf, "\251aut", "author"     , 0);
             mov_write_string_metadata(s, pb_buf, "\251alb", "album"      , 0);