🤳🏽 webRTC stream ingestion from browser tab, not camera

I was able to do a stream from my browser – info here Tell HN: Twitch.tv now supports WebRTC ingestion (Broadcast from your browser) | Hacker News
But I’m not able to fire peerConnection.setRemoteDescription when I init a stream with getDisplayMedia to capture my browser tab like I can when I use getUserMedia to capture my camera. I don’t know very much about WebRTC but I believe my javascript code is correct and want to check whether twitch blocks browser tab streams.