If you read https://github.com/matrix-org/matrix-spec-proposals/blob/matthew/group-voip/proposals/3401-group-voip.md https://github.com/matrix-org/matrix-spec-

If you read https://github.com/matrix-org/matrix-spec-proposals/blob/matthew/group-voip/proposals/3401-group-voip.md https://github.com/matrix-org/matrix-spec-proposals/blob/mat... it becomes apparent that the 'eventually consistent' part of Matrix is more of a hindrance in this case. Also 'the more federation and interoperability the better' is kind of contradictory to constantly reinventing extisting Internet Standards. I suspect VoIP over Matrix is not compatible with SIP or XMPP A/V calls and looking at current state of the matrix.org XMPP chat implementation they probably will never be.