This may not really be an answer but I DLed Quicktime to play a .mov file and there wasn't any audio with the resulting playback even though I have every audio codec (not?) known to mankind on this box.
I regularly decrypt, rip, burn and play DVDs and CDs with no problem using DVDdecrypter, Gordian Knot, ShrinkDVD, whatever, but this lack of Quicktime audio is rather amazing.
I cannot explain it.
All other DIVX, XVID, CDA, DVD, SDVD, ect play perfectly, but not Quick Time Player.
Go figure.