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:
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.
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.
Additional debug notes
Memory bandwidth may be constrained which is something that can be adjusted.
There are 2 possible solutions you can try:
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.
I have been dealing with the EXACT same issue since July when I updated to windows 10 on this model NUC. I have been pulling my hair out trying to find a solution. It is beyond frustrating that this hasn't been resolved by MS or Intel. I bought this NUC to run VMs and use as my HTPC and it worked great for that on Win 8.1 with Hyper-V; what in the world has broken it in windows 10, and why it hasn't been fixed for this long, is beyond me.
Same for me. All summed up, I've literally lost days fighting that, already. I got a NUC instead of a dedicated media player box thingy NOT to have to deal with stuff like that. And I already made a fool of myself several times, getting people to sit and wait while I'm restarting my OS over and over and over again. It's not like it's that unusual for one to use the always-on HTPC he/she already has to run some VMs as well, right? Especially after I stuffed mine with 16GBs of RAM for this very purpose.
I think this might be due to WASAPI being used to bitstream encoded audio on Windows 10 versus DirectSound for previous versions.
Nope, not the same issue. I'm getting regular Windows sounds just fine. It's the encoded AC3 and DTS audio that doesn't get passed through. Plus, the problem is intermittent. Also, in the other thread you're referring, I can see you trying to brush off the user's (Kratos) problem, referring him to your earlier post about the CPUs not supporting VT-d, despite him having stated clearly that his CPU (like mine) does, in fact, support this feature. I don't like where this is heading. No, this it not expected and this was working before. Like others stated, the sound playback is working fine with other brands of graphics cards so, with all due respect, I strongly believe it is your job to get in touch with Microsoft to get your drivers to work properly, not ours. I'm at the end of my rope with the experience of using Intel NUC and I insist to have this issue investigated properly. Before deleting or moderating this post, please bear in mind I'm not going to recommend Intel products to any prospective buyers given the current state of affairs. The responsive support that really means to help is currently what could change my view.
The thread you linked to does not have a resolution as you indicate there that the root cause is related to the CPU not supporting Directed I/O (VT-d) which is very much not the case for the NUC D54250WYK. Thank you for trying to help but you are misdirecting people on this issue (intentionally or otherwise I can't be sure).
The OP in that thread stated that his PC was using a Gigabyte motherboard with an i5-4590. In you replies you stated the issue was because his CPU didn't support Directed I/O (VT-d) which, for one, is completely false (see: http://ark.intel.com/products/80815/Intel-Core-i5-4590-Processor-6M-Cache-up-to-3_70-GHz Intel® Core™ i5-4590 Processor (6M Cache, up to 3.70 GHz) Specifications). Also, another poster (Kratos) indicated he was seeing the same Hyper-V / HDMI audio problem on the NUC D54250WYK using the i5-4250U which clearly supports Directed I/O (VT-d) as stated here: http://ark.intel.com/products/75028/Intel-Core-i5-4250U-Processor-3M-Cache-up-to-2_60-GHz Intel® Core™ i5-4250U Processor (3M Cache, up to 2.60 GHz) Specifications .
In the thread you conclude by saying this issue is expected behavior, which is a patently false statement. The D54250WYK NUC worked completely fine with Hyper-V and HDMI audio on Windows 8.1 and earlier. It only stopped working when the NUC was upgraded to windows 10 with Intel-provided windows 10 graphics drivers. If you want to defer to Microsoft and say it's a problem with Hyper-V in Windows 10, that's fine but please provide the link stating it's a known issue from them because I can't find such a thing. Until then I'm going to assume that Intel drivers are playing some part in the problem.
I have opened a support request case with Intel on this issue as directed by the Intel Twitter team (@IntelSupport). Case number is 00227472 and they have indicated they are performing testing related to this issue.
Please fill out the following form , make sure to follow closely all the instructions specifically the "How to repro" in order to investigate this matter.
Answers (N/A if not applicable)
Provide a detailed description of the issue
Bitstreaming of encoded (AC3, DTS) audio over HDMI fails (on the host OS) while Hyper-V enabled.
Does it fail every single time, or only sometimes?
If you can offer a % rate please do.
Brand and Model of the system.
Intel NUC D54250WYKH
Hybrid or switchable graphics system?
ie Does it have AMD or NV graphics too?
Make and model of any Displays that are used to see the issue (see note2 below).LFP = Local Flat Panel (Laptop panel)
EFP = External Flat Panel (Monitor you plug in)
Sony Bravia TV through Yamaha receiver
How much memory [RAM] in the system (see note2 below).
Provide any other hardware needed to replicate the issue.
ie: Cables&brand, cable type [vga, hdmi, DP, etc], dock, dongles/adapters, etc
NUC [HDMI] -> Yamaha receiver [HDMI] -> Sony TV
Hardware Stepping (see note1 below).
Software (SW)<td style=...
You, my friend, are a genius. At last my setup is, once again, usable for me. While it's still a bug on Intel's side than needs fixing (so please forgive me for not clicking "This is the correct answer"), I can live with that workaround until they do. You made my New Year's Eve, all the best for you.
After much searching around, having the same problem, I found this post and disabling VT-d did the trick.
My system had no issues when it ran Windows 8/8.1, but after upgrading to Windows 10 bitstreaming stopped working.
Tried different versions of KODI, drivers (Intel audio) and even re-installed a couple of times to see if that would trigger anything, nothing.
Installed latest Windows 10 b.586, no change...
Re-installing Windows 8.1 and it worked again, switching to Windows 10, no sound...
Was going insane!
Just diabled VT-d and now I got pure audio again.
Now my Hyper-V lab is not working
Keeping fingers crossed Microsoft/Intel will work out how to solve the problem.
Thank you for your patience and time.
This is still under investigation and as soon as possible I will get back to you.
Since the second Windows 10 update HDMI passthrough stopped working. I have a NUC6i5SYH and now have to disable HDMI in JRiver to get Multi Channel PCM passed through to my Denon. I will try and see if VT-d disabling restores HDMI passthrough.
marszi, thank you so much for this! That will work for now and I appreciate you posting as it will save a lot of folks the headache myself, Zbig_T and I'm sure many countless others have encountered.
Just an update from my end:
Intel Support Center hasn't touched my case and I'm not holding my breath on when I might see a reply. As I mentioned before VT-d is fully supported by the D54250WYK CPU and Chipset but it appears there is a bug with it that is currently only affecting Windows 10 when Client Hyper-V is enabled. I see that VT-d allows direct access to a PCI device for a guest VM which cuts down on emulation overhead of virtual PCI devices (typically used for direct access to a NIC). My educated guess is that there is a bug somewhere between the new hypervisor for Client Hyper-V in Windows 10 and the Intel display and/or chipset drivers.
The issue could be something on the host OS/hypervisor side of Windows 10 but I have called Microsoft to get a case opened with them and had 3 different reps tell me that they do not offer any support of Client Hyper-V and that I would need to call enterprise level support with my credit card number to pay them to troubleshoot. Yeah, no thanks I'm not paying them to fix their own issues. At this point I'll just use the workaround of disabling VT-d in the UEFI and wait around to see if any new updates from MS or Intel explicitly address the issue.