We just put together a brand new computer and have finished the mythbuntu installation. Noticing some very weird problems in video playback on certain files.

I have a copy of Planet Earth and Life from BBC that are all mkv files that play spactacularly on my computer in vlc player. The problem I am having is when they are playing in Mythtv the video is great, and music and background sound is beautiful but there is no narration. I only see one audio track in vlc so I don't think its that. I am very new to linux and mythtv so any help would be extremely appreciated.