Playing videos in VMs lags

User Support
1

When I play videos in VMs, they are barely watchable due to extreme lagging. I’ve tried different media players:

  • Parole, which can’t play MP4 files because it lacks the necessary codecs

  • VLC, which doesn’t display a picture

  • mpv, which lags significantly

I tested this on Fedora 43, Fedora 44 XFCE and Debian 13 templates (in Debian 13, VLC shows a picture but is also very laggy). I also tried playing WebM videos, which worked better but still have performance issues.

Is there a way to fix this? On a different laptop which also runs Qubes, videos play fine without any performance issue, however libreoffice documents cause tiny performance issues.

2

Export templates and app qubes from working to non-working machine and try and tell. Both for videos and libreoffice.

3

.

4

Unfortunately it is the same result.

5

I could offer him whole vlcrc file that works for me, but I am sure that wouldn’t help too.
vlcrc.log (95.7 KB)

P.S. rename vlcrc.log to vlcrc only. I had to do the hack to be able to upload the file.

6

In general, this is a known issue. Without GPU passthrough or hardware acceleration with SR-IOV, you’ll be constrained by your CPU’s software rendering capabilities. Will work well on some platforms and not-so-well on others.

7

I don’t know why but using the Whonix 18 workstation instead of Debian or Fedora fixed the issue. VLC can play the same Videos there without insane lags.

8

I knew our tips wouldn’t help.

Good for you! You should mark your post as a solution so other users could benefit from it too. Is working Whonix 18 workstation connected to internet?

9

Try disabling Display compositing
Dom0 → Settings → Window Manager Tweaks →Compositor →Enable display compositing (disable this)

Then try VLC in Debian 13