I only understand the basics of WebRTC. In this context, I don't know the purpose of using WebRTC for generating the video. Your video does little to explain what is happening, or the use case for it.

What is the value of recording an HTML canvas? Why are you saying this is an "editing tool"? Why does your documentation reference Blender, when none of this code interfaces with Blender at all? As far as I can tell, your project takes an existing 3d rotating WebGL cube and renders it to a cropped video. A far cry from an editing tool, so far as I'm concerned. And your titles imply there's audio editing but none of that is demonstrated or explained.

Plus it's a bit of a hassle to find the code for your actual project, which I had to navigate through an empty repo to your forked repo and then get the difference from the upstream: https://github.com/gfxfundamentals/threejsfundamentals/compare/master...udexon:master

Your main code libphos.js doesn't exactly scream "readable" either. But I don't really do JS, either. I'm also assuming I must be missing something because I don't see any code referencing ffmpeg either.