I+m running ubuntu edgy and mythtv in 1280x720. When i play some 720p movies on my htcp i get the worng aspect ratio. How have you configured your environments "xorg and player" to get the correct aspect ratio? When i play my movies i just execute mplayer "movie" and with no parameters i get the wrong aspect. Any help is very appreciated.

put monitoraspect=16:9 in your .mplayer/config