From the specs on the ATI HD 3800 specs:
Integrated Digital Outputs – Enjoy your digital content the way you want to, with built-in HDMI that includes 5.1 surround audio for big screen entertainment
looks like 5.1 is the best you are going to get for now. Not having read the links posted above, my bet is that it is a hdcp integration issue.
FWIW, I found a 2005 MS white paper on drm in Vista. Holly crap!! No wonder Vista takes so long to boot and even longer to start a movie. Crypto keys, handshakes and hardware chain verification up the wazoo.
I think I'm going to change my vista startup sound to jingling keys...
Wondering why ATI might be putting an audio chip on its graphics card? The white paper suggests its a drm requirement.
Oh, and my favourite line from the paper? "While it is not required to implement this blah blah, it is suggested that this is a good way for the hardware vendor to show its commitment to content protection."
