Custom Video Broadcasting App without third party API Usage

We're looking to build a video broadcasting app that can broadcast a video to YouTube, Facebook, or to any RTMP endpoint with a Layer from the website URL on it: This Means, the stream should consist

A. Video Stream
B. Overlay From Web URL/Endpoint

Something similar to the Prism LIVE app, but we just want a web URL overlay

And live stream it.

Thank you