Multiple screen sessions failing when playing video


Trying to find hint for a problem with using multiple desktops via fast user switching on a Mac. It appears that some applications playing video (EyeTV, QuickTime, Skype) freeze when a user connected via VNC interacts with his desktop. Rainbow wheel is displayed and nothing happens until the user at physical screen switches to another application and back.

VLC is apparently not impacted by the problem. Here is a report where other EyeTV users discuss the issue:

Elgato claims they need to be “active” users, while it is the case. My posts in that thread disappeared somehow, not sure what is going on. But considering other applications having the same problem, it appears more of Vine server issue.

I would appreciate if someone could have a look at this.

It’s certainly not a restriction we have intentionally put into Vine Server. As our page on multiple desktops mentions you can run into problems if the application is using hardware resources. In this case possibly the video card driver isn’t capable of taking simultaneous input from multiple users and it’s probably more inherent in the underlying API’s that Vine uses.

That said, I would recommend experimenting with the “Use OpenGL” flag in the latest version of Vine Server, linked on our downloads page.

I do not see the problem as a ‘restriction’ of Vine server.
At the same time I do not see how the backgroung user can compete with access to video hardware.
By definition the background user does not interact with real video card, mouse or keyboard.

To me it appears like a possible issue in Aqua itself,
where Apple did not expect someone interacting
with desktop that is fast-switched off.
And specific applications using a particular call to display video can get impacted here.

Certainly Apple does not officially support multiple desktops, but I do not think they would do this intentionally. But in this grey area they probably won’t accept a bug either.

Perhaps Vine server could work it aroud somehow:. I will in any case try the new version with Open GL.

Ideally the VNC server should work similar as Xvnc under unix, creating virtual desktop without any relation to actual display hardware.
I do not think Apple provides similar solution for multiplatform clients even with X-server.

It appears that the problem is not limited to video applications, there must be something common to the programs, see

I tried 3.11 with opengl but it does not seem to really help. Even worse, I am not able to connect to the session after it is fast switched off. Also observed another issues, like no keyboard input or session hang.

Same issue. Plex, VLC, doesn’t matter… Video freezes (audio continues) unless clicked/dragged, until background user logs out.