HDMI audio pass through / bitstreaming not working with AMD High Definition Audio

[londonjazzcat]

I have a Denon AVR connected to my HP laptop via HDMI.

This set up is replacing a system I no longer have - desktop PC, Windows 10 with an old Nvidia graphics card.

I can get surround sound working from my HP laptop but it will not pass through audio to my AVR. This should not be a technically advanced thing for the HDMI to do - it just needs to allow it when software is set up to do it.

For years I had Media Player Classic MPC-BE on my old desktop and it bitstreamed / passed through audio to my AVR no problem. Now with my HP laptop I can not get any application to bitstream to my AVR.

Is there any known reason why the HP HDMI could not support this and therefore restrict applications to sending PCM signals?

My Denon AVR shows up as a sound playback device in Windows 11, via the AMD High Definition Audio Device. I have it set to "stereo", since this is the known way to get Windows to pass through multi channel audio to an AVR. If instead the 5.1 or 7.1 speaker configuration is chosen, the AVR switches to "multi-channel in" mode which is very definitely not bitstreaming. I do get surround sound with the device set to stereo but my AVR does not recognise any audio type as it would with bitstreaming - it just says it is getting a PCR signal which is the typical fallback when bitstreaming does not work.

[londonjazzcat]

I can now confirm that it works in Windows 10.

I set up my Laptop to be dual Win 10 and Win 11 boot.

At first, Windows 10 could not even see my Denon AVR and only had stereo speakers as an option with no supported encoded formats.

I ran the HP driver update utility but it told me everything was already up to date.

I then downloaded the update utility from AMD which did find my 470M graphics and installed a new driver for it. After reboot, my Denon AVR was listed with all the typical supported encoded formats. HDMI pass through worked.

I then went back to my Windows 11 and tried running the AMD update utility there. Unfortunately it was not a magic fix there because it says the graphics driver is up to date.

So, I now know that the HP HMDI and AMD graphics can pass through high definition audio. It seems likely to be a Windows 11 driver problem that stops the HDMI bit streaming audio in Windows 11.

[londonjazzcat · Accepted solution]

Solved by re-installing Windows 11 and then running the AMD driver update tool.

I ran a test on the partition I had dual boot Windows 10 by overwriting that with Windows 11. Sure enough, audio pass through worked there so it seems my Windows 11 drivers were messed up.

I tried an in-place "update" of Windows 11 but that failed. I then tried an AMD driver installation with its "factory reset" option for the drivers, but that failed. So, I went for a reinstall of Windows 11. The AMD driver update tool has installed AMD High Definition Audio driver 10.0.0.38 which I already had installed but this time on a clean install it works.