HDMI audio bitstreaming (passthrough) not working with Hyper-V enabled on Windows 10

[ZTrze]

Intel NUC D54250WYK, Windows 10 Professional x64, latest drivers (Graphics: 4331; Intel Display Audio: 3182), Hyper-V enabled. Since several months (and through several drivers' versions) I'm struggling with passing the encoded movie audio (AC3, DTS) through HDMI. Everything's fine when not using Hyper-V. When it's enabled (and having it disabled is not a solution for me), it's a hit or miss approach to get working bitstreaming (MPC-HC, Plex; doesn't really matter) to my Yamaha receiver after booting. When I do manage to get it working by rebooting several times (haven't been able to find any pattern to that), it works only until any of the following happens:

• I log in remotely via RDP and then re-login locally
• I log in locally as another user
• some undefined amount of time (hours, days) passes, during which "something" breaks the pass-through functionality anyway.

After any of the above, I have to keep rebooting my OS until I get working bitstreaming again. Rinse and repeat, ad nauseam. It was working just fine up to Windows 8.1. Oddly enough, DTS-MA seems to work always, even when AC3 and DTS don't. Not cool.

[EGome3]

Thank you for linking me to to this post. I too disabled VT-d yesterday and I was able to have Hyper-V installed while keeping HDMI sound. While like you all, not a big fan of this work around stuff at least I can use hyper V again. I just have a couple simple VMs on there so the VT-d feature probably won't affect me much but would like to see the root cause figured out. Either way I will keep an eye on this thread as well and will also report if I find anything else out.

[Bryce__Intel]

Could someone verify if setting audio to "16 bit, 32000 Hz" or "'24 bit, 96000 Hz (Studio Quality)" works around your issue? I've had it reported this resolves, though I personally don't have 16x32000 setting on my system to try. Please let me know if you do/don't have the setting and if it resolves the issue if you do have it.

[MHans9]

Hi,

I have tested this on an Asus Maximus GENE VI board with an Intel i7-4765T CPU.

It runs the audio through an Onkyo TX-NR545 into a Philips 4K TV.

Intel Display Driver version used is: 6.16.0.3191.

(Can see 6.16.0.3196 is now available, maybe its worth a shot...)

When vt-d is enabled (Windows 10, latest build) audio pass-through is still not working. Changing audio settings bit/hz as suggested in previous post did not change anything, still no sound.

Disabling vt-d (or installing Windows 8/8.1) and audio works fine again with vt-d enabled.

[MHans9]

Hi,

Would it be possible to get an update on this one?

Is is being looked into, can a solution be expected within a reasonable timeframe?

Taking into consideration that it can work (Windows 8/8.1) the solution should not be, I hope, to buy new hardware...

Thank you.

/Martin!

[Bryce__Intel]

Hi all,

This is currently in the replication queue awaiting the engineer to pick it up and build the setup to repro the issue. There's no ETA yet. Once it moves further I'll update again. Thanks.

[AAnis2]

I'm having exactly the same problem with i7-4790K CPU and Hyper-V enabled

Running latest drivers (version 20.19.15.4444) and Windows 10

Same here: DTS-MA and True HD seems to work with Hyper-V enabled, but not DTS and DD

All works as expected when Hyper-V is disabled

[MHans9]

Hi,

Windows 10 b.14393 is out (anniversary edition) any change?

...no, problem is still here.

Any unreleased alpha/beta drivers from Intel that we can try?

Thank you.

[Bryce__Intel · Accepted solution]

Resolving as OS\API issue. In this Windows thread the issue is noted as happening on 3rd party graphics as well. Most users reported seeing the issue after a windows update or upgrade of the OS.

http://answers.microsoft.com/en-us/windows/forum/windows_10-other_settings/windows-10-hdmi-audio-not-working/293eec79-e0f8-4837-bbd0-341cfc9bd446?page=1 http://answers.microsoft.com/en-us/windows/forum/windows_10-other_settings/windows-10-hdmi-audio-not-working/293eec79-e0f8-4837-bbd0-341cfc9bd446?page=1

Additional debug notes

Memory bandwidth may be constrained which is something that can be adjusted.

There are 2 possible solutions you can try:

1. When dual channel 8GB memory is used, the issue is no longer observed.
2. Increase or maximize the DVMT graphics memory allocation in BIOS. (In my case: DVMT Pre-Allocated 1024MB and DVMT Total Gfx Mem Max)

The memory configuration could be the difference between 4th, 5th, and 6th Gen products, which users report passing and failing cases.

As virtual machines share memory with the Hyper-V host, you will need to provide enough memory to handle the expected virtual workload.