Originally posted by XenonMan:
I would expect that THX can certify the receiver without taking the Audyssey into account because it can be turned OFF. THX won't care as to what processing you do downstream of the signal once it is generated from the player thru the SSP. THX appears to certify the output after the DTS/Dolby logics are applied but not beyond that because the codecs are used to process the original soundtracks in the editing phase and as such are part of the sound.
Movie soundtracks are edited/mixed in it's original PCM form. The lossy codecs are not part of that, those are simply "delivery" formats for theatrical or home versions.