I'm having quite a specific problem that might need a bit of explanation of the configuration first. I have a 4k display (Panasonic wt600) that I can drive at 60hz through displayport with full 4:4:4 colour from my GTX 780s. I recently upgraded from my logitech z5500s which were driven by multichannel analogue to a proper AV-receiver (Yamaha RXV-677). I can use HDMI to get 4k60 video but only at 4:2:0 colour which looks pretty terrible for text. Using just the HDMI output like this I can get audio to work fine with the receiver. GTX 780s--[HDMI]--Receiver--[HDMI]--TV However, what I want to do is use displayport to get the video signal with 4k 60hz 4:4:4 goodness and then use HDMI to send audio to the receiver GTX 780s--[Displayport]--TV |__[HDMI]__Receiver . The problem is that when the displayport cable is connected to the TV and using MST, the HDMI audio output to the receiver just won't work. Windows and the Nvidia control panel detect that the receiver is connected via HDMI and the receiver detects an HDMI signal. The receiver is set as the default audio device and using the test tone from Windows just gets no audio even though the bar moves for that device showing audio should be playing. If I switch the displayport to use SST (limited to 1080p or 4k30) then the audio device starts actually working. I'm using Nvidia 340.43 drivers at the moment and have Geforce experience installed. I have a few more ideas to test but I'm at work at the moment. I want to connect a second TV instead of the receiver to see if HDMI audio will work in that case. As far as I know the HDMI outputs on the second GPU are disabled during SLI so I want to try disabling SLI and using the second card to output audio. This isn't the solution I want for gaming though. I'm considering trying different driver versions. I'm not sure if this is a hardware limitation or a bug. In summary, HDMI audio won't work when using MST mode from displayport. How can I fix it?
Is display port part of the sound devices in NVidia CP? If yes, have you tried to turn it off in digital Audio menu ? It may help. It is probably an HW limitation or a bug in the driver. So the best is to ask the question to Nvidia directly to be sure. But not sure you will get an answer to your ticket As a workaround you can consider using the Intel GPU and its HDMI port. I saw on the web that your MB has an HDMI port. The counterpart is that you need to install Intel drivers
Thanks for the reply. I can't actually disable the displayport audio when it's set to MST which I find kinda odd. The displayport audio itself does seem to be functional during this though as I can get noise through the TV's speakers. I've posted on Nvidia's forum but not actually made a proper support request yet. I've been looking into using the Intel one but I've got a feeling there's some limitation on using it at the same time as a real GPU. I'll give it a go when I get home soon though, thanks.
I do not think that 2D and sound pass trough could be a problem. 3d rendering on both at the same time, it is another story... As you said, the best is to try. It should not take that long
Thanks, got it set up with Intel GPU. Was a bit of a job messing around with bios setting and getting PC to recognise that the GPU was there and then to get the drivers installed. Now for 4k through displayport on Nvidia and HDMI audio through Intel onboard. Got an extra 1024x768 blank monitor to deal with but that should be fine. I'm still kind of interested in the original problem though.
Have you tried setting it up the way you had it first AND the display port? Meaning you should have Display port hooked up to your tv and then 780 via hdmi--receiver--tv. Try hooking both up. Use the way it worked for audio, but use the display port for video. Might do nothing but just trying to help. I have mine setup like you minus the display port so im trying to think this through haha.
just saying have you made any of the 8 nv hdmi play back devices as the default or just plug and play? -right click speaker icon - click play back devices and have a look. -I use a sound card so I have all that junk disabled in device manage and never used it but when I went from dvi to display port windows made my monitor a play back device as in sound card , so you might want to disable that also
I agree. Right click on the little volume icon in the lower right of your screen. Right click on playback devices,click on the nvidia playback device and set it as default device. That should fix it. Also,I don't know if receivers are compatible with a display port connection. If not I'm not sure you can run an HDMI to your receiver and get sound thru one of the 780's,its possible. Does your motherboard have high def audio? If your motherboard has an HDMI out,plug into that. Don't use the video card. Use the onboard sound HDMI,the receiver will decode it anyhow,so it won't matter. That's how I do sound with my HTPC..
Yeah, I omitted that part from the diagram. It didn't make a difference. Since the TV was set to receive displayport, the receiver couldn't detect the TV so the PC just saw the EDID from the receiver. GPU, goat1: I've already checked the default devices etc. "The receiver is set as the default audio device and using the test tone from Windows just gets no audio even though the bar moves for that device showing audio should be playing." goat1, Receivers are meant more for home theatre so none I could find support displayport. Yeah, I got it set up with HDMI audio from the onboard Intel eventually. Cheers.
Also,make sure nothing is muted by accident. Going thru that onboard sound,it should work. There's just something goofy is all. Wish I was there to look at it
Cheers, I think it is genuinely a hardware limit or software bug now. Motherboard sound has been fine so far, at least. I managed to find another person in a similar boat on AVS forums. They said that they couldn't get audio working when using Nvidia surround with GTX 780s but it worked fine when the same monitors were connected but surround was disabled. Looking into using Ultramon to hopefully fix the problem of the phantom extended display where I can lose windows/the mouse by accident.
Can't you enable pass through on the telly and run an optical from the telly out to the logitech. that way you can keep using just displayport.
If only Lindy or cablesson made a display port audio extractor like they do for HDMI all would be solved. Maybe they'll make one now display port usage is on the up.
I can use the onboard Intel GPU to get full HDMI audio capability to the AV receiver. Optical from the onboard soundcard would have the same limitations making it not much good for games or newer blu-ray sound formats.
