Why WebRTC? I think that's more designed for Browser-to-Browser connections. You'd just need to stream an H.264 file using a <video> tag (and use a websocket for the input).
Streaming an unbounded file to a <video> tag can have fairly significant delay compared to webRTC. It's really more designed for one to many situations (such as livestreams or VOD) than one to one low latency.