Intel video-acceleration changes going from 23.11->24.05?

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1

I do game streaming from a Windows PC to an Intel NUC running NixOS and the moonlight-qt package. As part of the config for this device I have

hardware.opengl.extraPackages = with pkgs; [
    intel-media-driver
];

This NUC is new, so this is the correct driver. On 23.11 moonlight-qt correctly picked up this driver and video decoding was hardware accelerated.

However, I upgraded to 24.05 (I just changed which branch my nixpkgs input pointed to in my flake) and now at startup moonlight-qt says that it can’t find a hardware video decoder.

Is this a change in how drivers, etc work from one release to the next, or is it a problem with moonlight-qt?

2

Have you tried some of the troubleshooting steps in Hardware video acceleration - ArchWiki? Are there any messages in the journal?

3 
hardware.opengl

is being renamed to

hardware.graphics

I am not sure if that change has hit 24.05

4

check what’s in nixos-hardware repo for intel: nixos-hardware/common/gpu/intel/default.nix at 6e253f12b1009053eff5344be5e835f604bb64cd · NixOS/nixos-hardware · GitHub

I also have NUC (probably 1-2 generations old already), there are 3 packages i use there:

hardware.opengl = {
    enable = true;
    extraPackages = with pkgs; [
      intel-media-driver
      libvdpau-va-gl
      vaapiIntel
    ];
  };

(not sure about vaapiIntel there, got it from old wiki entry and it has been there ever since)
Haven’t tested specifically moonlight-qt, but vlc and firefox have hardware acceleration, no problem

This works both in 23.11 and 24.05 for me

5

That will probably never reach 24.05 as that’s a breaking API change.

We can check by running the following command, as the intel section on Accelerated Video Playback - NixOS Wiki suggests:

nix-shell -p libva-utils --run vainfo

If there are no errors, it’s more likely an issue with moonlight-qt.

We might want to add this to the wiki if we can confirm which drivers make it work.

6

So here’s what I’ve found. All the drivers exist both on 23.11 and 24.05, and the moonlight-qt revision is the same from 23.11 to 24.05.

The difference is found in the moonlight-qt logs. On 23.11 you see this:

libva info: VA-API version 1.20.0
libva info: Trying to open /run/opengl-driver/lib/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_20
libva info: va_openDriver() returns 0

whereas on 24.05 you see this:

libva info: VA-API version 1.20.0
libva info: Trying to open /run/opengl-driver/lib/dri/iHD_drv_video.so
libva error: /run/opengl-driver/lib/dri/iHD_drv_video.so has no function __vaDriverInit_1_0

So the driver exists, but on 24.05 it’s looking for a different symbol name that appears not to exist.

1 Like
7

I found similar issues on GitHub, but there doesn’t seem to be any apparent solution. However, I found the following configuration in nixos-hardware:

From this, I assume you need to add intel-vaapi-driver in addition to intel-media-driver for it to work properly.

8

Yeah I actually already have both of those drivers included

9

have you tried with any other software that uses hardware encoding? is it just moonlight-qt that have those issues, or all other softwares too?

in VLC, you will see the same kind of log when you open a video that supports hardware decoding

p.s. also it’s strange that it looks for __vaDriverInit_1_0, when it should be 1_20,
you can check exported symbols with readelf --symbols -C /run/opengl-driver/lib/dri/iHD_drv_video.so | grep -i vadriver
my guess is that’s something fishy with moonlight-qt, but i don’t know how libva picks init function and what env (or smth else) affects it

1 Like
10

Appears to be something fishy with moonlight-qt. VLC works fine with an H264 video and the driver is picked up, but on 24.05 it’s __vaDriverInit_1_21. That readelf command only shows that symbol as well, not __vaDriverInit_1_1.

11

I think the issue may be that libva for moonlight-qt expects a different driver version. At startup on both 23.11 and 24.05 you see this:

libva info: VA-API version 1.20.0

and on 23.11 that matches the driver version, whereas on 24.05 the driver version is 1.21.0.

12

Using moonlight-qt from this open PR solves the problem.

1 Like
13

is very old and unmaintained. Unless you know exactly why you need it, you shouldn’t use it.

2 Likes
14

thank you for pointing that out.

I see that it has been removed from the official wiki’s Accelerated_Video_Playback article, but it is still present in some other articles, i guess those need to be updated.
found in: