[floepie]

If it works in MCE, try changing the default DVD audio decoder to Microsoft mpeg1-2. If you have ffdshow installed, use that instead, and in the codecs section of ffdshow audio, select S/PDIF in the drop down besides the AC3 and DTS codecs.

If THAT doesn't work, get the latest AC3 filter installed and check the box where it indicates to use the AC3 filter in the DVD section of the MP config.

PDVD's DS audio decoder is problematic with many Media Center setups. When I originally setup my Vista MC and before I had an external audio decoder, I would specifically set it up to use PDVD7 for video decoding and MS's Mpeg1/2 audio decoder for the audio.

EDIT: I see you do use ffdshow, so use that as the audio decoder in the drop down menu and make sure that both DTS and AC3 codecs use the S/PDIF in the ffdshow audio config.