jitsi is an open server.  it makes connections to you when you want to chat with video, and for each person in the room.  it then delivers everyones video to each user, eliminating bandwidth issues caused by other video network topologies.
its neat. its called SFU architecture - and when you start getting serious about optimizing it, you end up reading things like this:
https://webrtchacks.com/sfu-cascading/

David Medina

no, jitsi does not require a membership, just a credential.  you need to have the app, it tokenizes your data stream from your phone or laptop to the jitsi SFU server, and then everyone who has the same "key" which is just the #nameoftheJitsiRooom  they can join.  
you can password a room. make a room "permanent" by always joining it, but the odds of some dippy do taking your room name is pretty low... plus, are you really that weak inside ? pick a new name.
you can also do cool stuff like have some callers dial in on video, some dial in on their phones, and like the voice users will show the phone number, so people on the call can know its them, oh yeah thats bobs number or thats theresa, etc-  its got a few other features, but you should just freaking read about it man :)

they have a website.   jitsi. something :D