I want to output uncompressed multi channel audio from my Windows 10 PC to my AV amplifier over HDMI.

I have it working, I've got my amp connected via HDMI using the integrated Intel GPU's HDMI port. I also have a separate AMD Vega 64 as my main GPU.

That all works, I get uncompressed multi channel audio showing up on the amp.

However that also means that the PC is extending a desktop to that HDMI output, if I plugged a display into the output of the amp I'd see a Windows desktop.

What I'd like to do is just send audio over that HDMI connection and not extend the desktop there. If I do this the sound device for that HDMI connection disappears, understandably.

I've tried forcing that sound device to be enabled again, with devcon, but it has no effect. In fact once I've stopped extending the desktop to that output the only way the sound device is enabled again is by rebooting.

Does anyone know if it possible to output audio over this HDMI connection without extending the desktop there as well ?

Seems like you're not the only one with this problem. Looks like Windows will create a display for any HDMI connection, even if you don't intend to use it.

What about running your HDMI cable from the computer to the A/V receiver, then, the receiver's HDMI output back to your computer monitor via yet another HDMI cable? That way you end up actually using the display. This could be thwarted if the A/V receiver does bad stuff to get in your way, like, limiting the resolution or refresh rate of the video signal.

Another option is, if you're only using a single monitor anyway, you can go ahead and let Windows create the display and then select "duplicate displays".

Another option I saw was to go ahead and let Windows make a display, but do the desktop arrangement, so that it's moved over down to like the lower left corner, so that your mouse is less likely to end up down there. And then hope that none of your desktop icons ever scootch down there. (And possibly use some other software to lock the mouse away from that desktop.)

Others have talked about disabling Pin 19 on the HDMI connector, but then others report that that doesn't solve all the problems.

Another option is something in this category (I don't know if this one is any good), which will extract the audio from the HDMI and send it out on a couple of different digital formats like optical and digital coaxial (if you have that as an option): https://www.monoprice.com/Product?c_id=1...=1&format=2 - This will still create a display, but you could put it inline behind the monitor and then you'd be running only one cable to the AV receiver instead of two.

I don't think ARC helps you in this case ( https://www.tomsguide.com/us/hdmi-arc-faq,news-26262.html ).

Anyway, some links:

https://hardforum.com/threads/is-there-a-way-to-output-sound-by-hdmi-without-video.1896250/
https://forums.tomsguide.com/threads/how-to-output-only-sound-through-hdmi.378729/

I don't think I can send it via the amp, or at least I don't think I'll be able to once I upgrade my monitor. It is an oldish amp with old HDMI that won't be able to pass through higher refresh rates. At least I think that is the case.

I didn't think mirroring the display would be a good plan for similar reasons, I'm not clear what it does to the refresh rate on my main display it is has to mirror to an HDMI port that can't get to the same refresh rates. That is something I'm going to investigate though.

Stopping the mouse from getting to that display seems like a nice practical solution. I'll bet there is a tool out there already to do that.

I've just experimented with organising the displays as you suggested and that helps a lot, though it does make it slightly harder to get back onto the main display when you do manage to mouse off

Optical/coax won't help, the whole reason for using HDMI was to get uncompressed 5.1 audio out. Optical/coax can only do two channels of uncompressed audio. And yeah, I'll never hear the difference, but I just wanted to see if it would work...

As you say, ARC won't help me with this one.

There are indeed such tools:

https://superuser.com/questions/1088286/how-to-restrict-mouse-to-current-display

However I'm not sure I need them. With the displays arranged not just diagonally, but pulled apart slightly, it seems I can't get the mouse to move off the main screen anyway.

The answer in that SU question suggests if you move the mouse quickly it will make it to the second screen, but I've not managed it.

Problem solved, thanks Tony.

Eh? I regularly use Optical for 5.1 sound. Even with a dongle to extract it from HDMI.

??

Optical cannot do *uncompressed* 5.1 channel audio

Ah. Okay, yes, my audio feeds are Dolby encoded or DTS.

My requirement was entirely unnecessary and nice-to-have, I arrived at it like this:

- it would be great to make use of that old AV amp and random collection of speakers (I upgraded the living room surround last year)
- it would work really well on my games PC
- hmmm, can't find any toslink cables
- bugger, my PC doesn't have a coax out
- hey, I could try HDMI, I have a completely unused Intel GPU with an HDMI port
- yippee, it works and I get uncompressed audio, bonus

They came "I wonder if I can get Windows not to extend the desktop over there".

Good fun, and quite inventive that!
One other thing perhaps: most of the mobos I have seen which have optical out, also have an onboard "coax" header with the correct signal levels.

Cheers

I have no doubt my motherboard has a coax header, but I’m better off with the HDMI. Coax has the same bandwidth limitations as optical.