Nvidia HDMI "not plugged in" (greyed out), video, but no audio

Hi all,

Here's my setup: Nvidia video card>HDMI out to Sony Home Theater System>HDMI out to Samsung HDTV. I use this to get 5.1 LPCM surround sound for video games. It worked fine until I did a firmware update on the Sony unit. Now, the HDMI audio is greyed out in Windows 7 audio playback options. Nvidia Control Panel sees the device as audio compatible, but Windows does not.

Audio DOES work if I connect a different display (through the same system). I connected an Acer computer monitor and everything worked normally. It also works it I connect it directly to the Samsung TV. The Sony unit works on its own or with the Acer monitor connected. When the monitor is connected, Nvidia Control Panel sees the home theater system as Sony AV System and Audio Playback reports SonyAVSYSTEM. When the Samsung TV is plugged in, Nvidia CP sees the home theater system as Sony Digital Display and Windows audio just says the cable is unplugged (doesn't report anything). I'm getting picture with this setup, but I can't even select the audio option.

I'm going crazy at this point, I have Sony working on it from their end and Samsung insists it's not their fault. Is this a Windows problem? I find it strange that Nvidia CP can recognize the unit and marks it as audio-capable, but Windows says a cable is unplugged. I've tried all recent driver options for both Realtek and Nvidia (Betas and stable). All drivers work the same under different connections described above. That the system works normally unless PC>Theater>TV makes me think that this is a pretty specific breakdown in communication with HDMI. PLEASE HELP ME!!!!

Update:
Sony representatives got back to me with the findings from their engineers. They insist that because my PS3 works on the setup, it must be an issue with my PC. Their best guess is that the devices are failing to handshake properly over the HDMI connection. Is there a way to update some kind of device list that forces Windows 7 to play nicely?

Although you are having some type of issue with the audio, its really an issue with the Video Card, since the Video card generates the audio for HDMI. If I understand your post, you are only concerned with HDMI audio and not the regular PC's audio (which is separate and thus the RealTek has nothing to do with it).

If you haven't done it, install (or reinstall) the latest NVIDIA drivers for your video card and see if that helps.

I went back and reread your initial post. Since the Sony update "broke" it, that would seem to be where the problem is. However if they think its a "handshake" problem between the Sony and the HDMI output in the video card it could still be the video card drivers. On the other hand Sony could be doing the typical Vendor "I don't know" or "Its not my problem" and pointing fingers at the other end, which leaves the user holding the bag trying to find the real problem and fix it.

I would still install or reinstall the latest NVIDA driver, as a start.