Configure MythTV
MythTV is really just a UI shell for all the multimedia tools that already existed in linux. Getting them all configured just right is the challenge.
MythTV has some built-in tools, like a DVD player, or you can configure it to use another external player, like xine.
MythTV->Utilities->Setup->Media Settings->DVD Settings->Play Settings->DVD Player Command xine -pfhq --no-splash dvd://