It works fine in Firefox (send and receive) as long as you don't need to play on multiple output devices. Currently you can enable a feature flag, use enumerateDevices() and play audio files on specific devices, but you can't hook up WebRTC streams to the devices.
enumerateDevices() should enumerate audio output devices (feature behind pref): https://bugzilla.mozilla.org/show_bug.cgi?id=1152401
Enable by default setSinkId pref: https://bugzilla.mozilla.org/show_bug.cgi?id=1498512
Alex Chronopoulos: "We keep it off because it does not work for everything. It works when we playback a file but not for webaudio or WebRTC. We want to add those too and we keep it off till then."