It gets the bits off the disc and puts them on the wire. There's no "sonic character" of the transport when using HDMI.
Audio related, here's the reason I'm not picking one up, and will wait for Oppo's next model (it'll probably be about a year from now):
With the BDP-83 you can't enable SAP and do high resolution decoding at the same time. It does not have the hardware processing required to do so.
Not a huge deal, but the PS3 handles this properly, so I'll stick with it for now. Basically, if a disc forces secondary audio, and you're not bitstreaming, it'll fall back to the core audio. There is an configuration option to disable secondary audio, but it can still be forced by a disc.
Really, the Oppo is a great player. But it doesn't tick every box I for the features I'd require before spending $500. My 60GB PS3 plus the Pioneer DV-79AVi, cover all my media playback bases. So until there's one box that does everything those two together do I'm holding off.
