The setup is: Gigabyte GA-MA785GMT-UD2H with an ATI Radeon HD 5670 video card. The latest Realtek audio drivers are intalled. The video/audio is piped by HDMI from the video card through a receiver to TV. When the receiver/TV are on before the HTPC boots, I get 5.1 audio output from the PC just fine. But, when the HTPC boots or wakes from sleep and the receiver is not on yet, I get only stereo output - that becomes the only option in Realtek HD audio manager under HDMI output. It seems that the driver is too smart for its own good and detects that there is no 5.1 playback device. I've searched everywhere for an option/solution to stop it from doing that and just trust that there is a 5.1 playback device.
Correct me if I am wrong. The ati 5000 series has 7.1 audio though HDMI. I assume the realtek audio is your onboard audio. The hdmi audio is from the ati driver not the realtek. But back to the subject, that is normal operation. My Xbox 360 does the same thing; just remember to turn on the receiver first before you turn on pc. Auto detection is a good thing. You would not want multichannel out to a stereo setup; you will lose the vocal of the center channel during movies. One might think that there is something wrong with the movie. The safest default is stereo.
If there is an option to make the digital multichannel output stick regardless of the target, I would like to know too. But the work along is to use multichannel analog output. Set the receiver to multiple channel inputs and you are set.
thanks for the reply. I agree that turning on the receiver before PC is a workable option, I just find it annoying to always have to do that. Plus, I'm not the only one using the system - my wife would like a simple, fool-proof way to get to watch TV on this rig, without complicated instructions The worrisome thing is that resulting sound levels are actually quite different between the stereo and 5.1 modes, and requires changing the PC system volume and/or the receiver volume between the two. This adds to the complications.
I'd like to stay away from the multichannel analog option if I can - don't want all the extra cabling, and then I think I'd have to set the receiver to the analog input, and route the video hdmi from PC straight to TV. This would lose the connectivity between TV and receiver that they do through hdmi (basically aware when the other is on, allowing for one-button power on/off of both. again, shooting for ease of use here)
yep, the 5670 has 7.1 capabilities, I just happen to have a 5.1 setup. Realtek drivers are initially indeed for the onboard audio, but it seems that once the standalone 5670 video card is installed and the video/audio is set to output through its hdmi port, the realtek audio driver is still in charge of the audio - it's just routed to the card's hdmi. I don't have prior experience with this kind of setup, but no ATI drivers (CCC or otherwise) control audio in this system I just put together.
All in all auto detectionof the target playback device capabilities is good until is gets in the way of doing things. It's like - if I run a bunch of data crunching on the PC overnight, and just turn off the TV screen while it's running - should it forget all the display setup options just because it's off?