Interruptions and audio cracking during video conversation

User Support General
21

@Talkabout

Thanks for the feedback. I hope you enjoyed your vacation!

Have you also tested without network, e.g. recording something locally, then checking the result?

No, didn’t test this. Wondering how this might be related, can you elaborate?

If it is a networking issue, some data may be lost/damaged in transit, thus resulting in bad sound.

Considering you use BT as well, I would consider it a potential source of issues too, i.e. trying a different BT adapter on different USB ports…

If you are able to isolate the issue from network and BT, then we can be sure to say “It is an issue with Qubes for sure”.

Thanks for your help so far!

I don’t see how I have helped. I am rather searching for the reason myself.

22

So, I have been testing the exact same thing: qTox on 2 separate Whonix-17-based VMs.

Result: No underruns in journal. Sound is fine. I have not touched quantum.

While sys-whonix is the netvm, 360p is achievable but 240p is more stable.

Tested switching the netvm to sys-firewall, then even 720p was running smoothly. I had the camera pointed at a TV with quite dynamic pictures.

Overall, it seems Tox chat always needs about 30-40 seconds to “stabilize” the conference initially, only then things look smooth (video and sound). Until then, there are these cracks and smears.

My conclusion so far:

  • It is not hardware
  • It is not Qubes OS
  • It seems partially related to qtox and network speed
  • Some recent update may have fixed the underruns (no idea how to check)

I have not tried a newer version of qtox, only the one that is on the official repo provided by Whonix 17.

For the sake of a more complete testing, I also downloaded and installed the much praised SimpleX chat.

Result: Only chat seems to work, regardless of network settings. Any attempt for audio or video call doesn’t even notify the other party about it.

No idea what else to try.

23

@qubist thanks again for putting effort into this topic!

After using hardware acceleration in vms (via sriov) those issues are mostly gone. I am able to listen to sound without cracks and also my mic seems to work properly in Teams. Not sure though if this is a result of the hardware acceleration or if there were changes in the underlying code base.

Sometimes when starting Teams discussion I can hear cracks at the beginning, but the disappear while the call is ongoing.

So for now I don’t see any issues on my side any more and would like to thank all people involved here for their attention!

24

That’s great news.