It might be possible with Jitsi, but I don't like the program in general. I
tried it on a Windows computer and it was very buggy, even for general use.
There were problems like windows not rendering properly and other. With the
other programs, even if there are problems with voice calls, at least in
general (for text) they work good.
I wasn't able to make a call between Jitsi on Windows and other XMPP clients
on GNU, although it might be possible if you fiddle around. In any case, I
would appreciate reports on how Jitsi works when you test it.
Also, Jitsi supports only H.265 video.
