Originally Posted by sahmen
--Yes the 818 normally outputs audio to my speakers, except where the Zotac HTPC is concerned, in which case I only get the video on the TV, and no sound from my speakers. Sorry for the confusion.
Ok so you got the picture, but no sound to the receiver? But when you connect your HTPC directly to your TV, you got sound? I'm not sure what's wrong in that case. What does the 818 says it's getting? E.g. using the display button multiple times, you'll see first the input source and listening mode, then the audio input format, and then the input and output video resolutions.
The XBMC issue is indeed tricky: Do you have any suggestions?
Well you can select "analog" in XBMC's sound settings and it will work more easily. That setting is not very well named as you won't be getting analog sound at all. It just passes the stream to Window's sound server, which then handles everything. When using this, then make sure that the corresponding windows output device (i.e. HDMI) is correctly configured (e.g. for 5.1 audio -- you can test this with a button in the configuration wizard). Your receiver will then get multichannel PCM and will display MULTICH by default.
You can also use XBMC in passthrough mode, where it will bitstream compatible content to the receiver. To do this, the HDMI device in Windows must be set so it can be controlled by any software. Then, in XBMC's sound setting, you have to select HDMI output and select the formats that the receiver can decode (I think the 818 can decode all of them). Now in the passthrough output device on the bottom of the settings page, you have to select Window's WASAPI output for the correct HDMI output. If all is set correctly, a DTS HD Master Audio track for example will be bit-streamed to the receiver directly, with no system sound mixed in it.
One complication I have is that XBMC sees many HDMI outputs for my single nVidia card (rencent nVidia cards have multiple virtual outputs), and the "correct" output is not always the same. I have not resolved this yet... In the mean time, I don't notice any degradation using "analog" output (i.e. letting the OS decode the stream and sending PCM to the receiver).