>I have never played with this one -- but perhaps this is worthy of a look?
>https://jitsi.org/

Tried it out and there was a flaw in the documentation, or rather in instructions for setup. It asked for server name, without any explanation of wtf "server" means in this context. It turned out to be the name of my machine (and wow, it couldn't offer that as default?) but then there was no way to redo that part of installation so it kept crashing, and I couldn't find where its config files to put that name (this is linux).

And then I found out, reading further through config files, that it actually connects to Google's servers to initiate a p2p chat or video, and then switches to p2p only if there are only two parties. So, ahem, all open source and independent and whatnot - and then it goes through a monster's cloud. Thanks, but, no, thanks.