How to combine streaming and gameplay?

Question

Game development

On the web client (on the site) you need to make a game with a stream stream.
The bottom layer will be streaming then rtmp/flv.
DOM elements will be placed above it.
And above them, you need to make a game animated process for which I think to use phaser.io
I can’t change the video stream, but I can change the framework for the game and remove the html markup that goes with the second layer. But I didn’t understand how to combine all this with phaser.
Please tell me the best way to solve this problem. Or maybe take another framework for animation.