I just wanted to give an update on the caveats I mentioned in my post above (#232) and outline a few things people should check when trying to get their on-board HD and / or Intel CPU HD audio to work:
1. Two-second handsake delay: Thanks christiaanb for the link to AVR Guard (http://www.avsforum.com/t/1317491/silent-stream-bug). Although I consider it a temporary fix, the little utility did eliminate the loss of the first two seconds of audio via HDMI. I wish Microsoft would implement a similar fix natively for their OSes or that the BIOS and / or audio drivers would address this annoying issue. For now, people should definitely try AVR Guard and make sure to select "Run from Startup" via the program's taskbar icon.
2. Stereo Only: The Intel Display Audio drivers seem to automatically detect the maximum number of audio channels that the last device in your HDMI chain is capable of. In my case, I mistakenly set my Onkyo TX-NR717 (7.1) receiver to pass the HDMI audio to the LG 3D HDTV. Since the TV is only capable of 2 channels maximum, that is all I could see in the audio properties. As soon as I disabled the HDMI "Audio TV Out" pass-through on the receiver, Intel Display Audio presented me with the ability to configure 7.1 surround sound, including Dolby TrueHD and DTS Master Audio as supported formats. All 8 channels work using the built-in Windows Sound tests. When I turn the receiver off, it still passes the audio for the last selected mode (PC) to the TV. In that case, Intel Display Audio again detects a maximum of 2 channels, which play just fine for TV viewing.
3. Other HD Audio Device: For me this represents the on-board Asus Z87M-PLUS motherboard HD Audio (when enabled in the BIOS). Even with the latest Realtek HD audio drivers, I couldn't ever successfully get any sound via HDMI, even though the volume meters indicated working audio. I noticed that in Properties > Supported Formats for this device, HDCP was not supported. I contacted Asus about this and the online agent could not confirm (or deny) if the on-board HD audio was capable of 7.1 via HDMI. I couldn't even get 2.0 stereo and I'm sure lack of HDCP support is to blame. The Asus agent suggested reloading the latest Realtek drivers and even reinstalling Windows! Really?!? How typical. For now, I'm happy with my HDCP-capable Intel Display Audio.
4. Suspicious cmd.exe: I'm not sure why my AVG 2014 antivirus considers this file "suspicious" (not "infected"), but it happens infrequently. I've scanned just that file in my Windows/System32 folder and it comes out clean. For now, I've created an exception rule for it.
5. Intel Graphics System Tray icon: Still keeps coming back no matter how it's configured in Graphics Properties. I think this is a small bug in the latest driver. Kevin, could you send a quick note to see if a tech can check on this?
If I find additional tips, I'll post them here. I do check this forum often and I hope everyone can get their HDMI 7.1 audio working sooner than later.
Take care,
RedEyeGuy.