riot.im hosts its own Jitsi instance which is built into the UI, so hitting the call button in a room will spawn an embedded Jitsi call in the room.

Recently we added the option for people to use their own self hosted Jitsi instances, if they prefer.

(1:1 calls at the moment are normal WebRTC, directly over Matrix)

I might be breaking the rules, but can you point me towards any information about how to integrate my existing self-hosted jitsi server into my self-hosted matrix install? Finding this seems elusive.

I tried and i don't think its easily possible.

Thanks for the clarification!