Matrix supports both video and audio chat over WebRTC. IIUC this provides strong e2e encryption and very good performance (it is the best looking video call I have used as they don't seem to really have any limit on the resources used because it is p2p). However it is limited to 1:1 right now.
Element (and some other clients, but I don't think it is part of the standard) also supports multi-user voice and video using Jitsi which works very well but you loose e2e encryption (although IIUC Jitsi has some experiments for this) and need to run it separately.
Element (and some other clients, but I don't think it is part of the standard) also supports multi-user voice and video using Jitsi which works very well but you loose e2e encryption (although IIUC Jitsi has some experiments for this) and need to run it separately.