Uhh, Jitsi? Jitsi Meet? Free and open source of course.
Jitsi has ZRTP encryption. Jitsi Meet uses WebRTC and its encryption isn't the same, but from the academic research papers I've read such as "Stegozoa: Enhancing WebRTC Covert Channels with Video Steganography for Internet Censorship Circumvention" from June 2022, it's convincing enough for me to have set up my own Jitsi Meet server on a Debian Linux Virtualbox machine.
From the paper:
"Given that the peer-to-peer connections carrying the video
streams are encrypted end-to-end, not even a state-level adversary
with unrestricted access to the network infrastructure will be able
to observe the raw video content of the WebRTC streams. "
Jitsi has ZRTP encryption. Jitsi Meet uses WebRTC and its encryption isn't the same, but from the academic research papers I've read such as "Stegozoa: Enhancing WebRTC Covert Channels with Video Steganography for Internet Censorship Circumvention" from June 2022, it's convincing enough for me to have set up my own Jitsi Meet server on a Debian Linux Virtualbox machine.
From the paper:
"Given that the peer-to-peer connections carrying the video streams are encrypted end-to-end, not even a state-level adversary with unrestricted access to the network infrastructure will be able to observe the raw video content of the WebRTC streams. "