Quick note on webrtc: It requires every client to stream video directly to every other client, meaning the amount of bandwidth goes up exponentially with the number of users in a chat. It really really doesn’t work well for video chats over ~10 people, or people on poor connections.
As I said, I work mostly remotely in a large team with daily video calls, we’ve tested basically every video chat client going and Hangouts is the only one that works with big groups at all.
I too would prefer an open solution, but they’re all just terrible for this at the moment! Motivation to write one 