We have a bug to add generic jabber support, but as long as no program manager allows that feature, teams can't work on it (yeah, that sucks). About video call over xmpp, the feature is being worked on but I can't promise it'll be released in next update. Maybe 3rd party apps like peregrine allow that?
mc-tool add gabble/jabber jabberorg string:account=myuser@jabber.org string:password=mypassword mc-tool list mc-tool enable gabble/jabber/myuser_40jabber_2eorg0