A little while ago I got inspired to put something together that people could download and use freely. It’s a good start, but by not complete - it doesn’t (yet) take advantage of the Asterisk 16+ features of a multi-steam video, but video calling is possible, even text chat.
You can check it out, clone it, etc:
How-to video in YouTube:
P.s Although the Channel focus is on Raspberry Pi based deployment, it could easily be applied to any Asterisk box - the principals will be the same.