HTPC and Surround Sound

As I mentioned in my previous post, I am happily using Netflix for my scant television needs. My current setup is using a Roku (first generation w/ HDMI) on the extra television, and a Home Theater PC (HTPC) that I built for the main television. The Roku is ok, it’s a little laggy and annoying at times, but it’s acceptable for the occasional use it gets. The HTPC has worked pretty well and I’ve been pleased with it.

Eventually I decided that my TV speakers were horrible and it was finally time to give in and purchase an A/V receiver and some speakers. I found a pioneer VSX-1022 (FYI for anyone interested in buying this, the “upconversion” for video does not work for the Xbox, the whole reason I bought the unit) and bought a 5.1 set of Pioneer speakers.  Everything hooked up easy enough, but I could not get surround sound working on my HTPC over HDMI. To make matters worse, I couldn’t even use any of the Dolby/DTS options to upmix the audio, the receiver would only allow stereo and PCM. After tinkering around with this, I have finally found a solution which I am sharing here for anyone else that might have this problem.

Once you configure your playback device to use more than stereo, windows appear to output all sound as multi-channel PCM. If it is a stereo source, as far as I can tell, windows still sends the channels; they are just null and void. This was stopping my receiver from upmixing the audio, since as far as it could tell the audio source was surround sound.

The problem is that windows is processing the audio, which is not want I want. I would prefer for the receiver that I bought to handle audio processing. As far as I can tell, my only option is to try and force each application to output using bit-streaming. This means enabling exclusive mode (make sure that box is checked!) and enabling WASAPI for the application. This causes a perfect bit for bit copy of the data to be sent straight to the receiver for processing.

Sadly, it seems that not all applications can use this. I have downloaded a WASAPI plugin for Winamp, and it has been working well. I hear that I have some options for Media Player Classic, although I haven’t started down this path yet. I can not get Netflix to use WASAPI mode and not PCM. If anyone has any ideas on how to go about this I would love to hear them. Currently, if I want to upmix Netflix using Dolby ProLogic II Movies, I have to configure my playback device back to stereo mode. I would love to know the reason why windows has to output everything as multi-channel PCM. It is one heck of a stupid oversight on the developer’s part, unless of course there is a valid technical reason for it that I am not aware.

Hopefully this will save someone else a few hours of trouble.