PCM stereo is uncompressed, thus higher fidelity than Dolby which is fairly heavily compressed. I know no reason why PCM should fall out of sync. Have you tried these discs on more than one DVD player, or on a computer, and is the problem consistent? Is the sync consistently off by the same amount from beginning to end, or does it begin in sync and get further out-off-sync as playback continues? iDVD generates only PCM tracks, not Dolby, and I know of no generic problems with sync on IDVD generated discs. So I suspect either the discs you're having trouble with were authored improperly, or your DVD player has some issues keeping up with the higher bitrate generated by PCM (though I have not heard of this being a common problem). ---- Learn to speak like a film/TV professor! Listen to the ScreenLex podcast: http://www.screenlex.org