One of the kids' DVDs I ripped last night to put into iTunes is in Dolby Digital Stereo... Not Pro Logic II.... Which I thought was really strange... From what I could research it seems to be some sort of compression format? Like mp3? So when I did ac3 passthrough it plays fine via appletv 2 and Denon 1610 avr to tv but on QuickTime via computer I get loads of digital noise... Which seems kinda silly for a format that is supposed to save space on discs and play on loads of things... Should I just rip to stereo 320kbps? There is no surround sound data/instructions in this format anyway?