If you take a media center recording and process the .WTV file through Moviemaker (essentials version), the sound is always out of sync and gets worse the further into the movie you go. Unwatchable output. It doesn't appear to matter which output format you use. This is on an AMD 940 quad with GTX460 GPU. I can run the same WTV file through MediaEspresso on the same hardware and it converts to another format properly, without the sync issue.