I've worked on a few recent projects involving the WebAudio API, and just offhand, a lot of the samples you see online are actually either broken in various (hello never releasing and closing recording nodes) or just work with specific chrome quirks (needing processing nodes connected to output nodes), so what you want I haven't done, I doubt anyone you'll find as a freelancer has, but I can work with you to figure out first if it's even possible. The API lists an ability to feed in a processor and be given formatted output, but it doesn't look like any browser actually implemented that part of the API, so you're looking at taking individual frames and working with them. This would basically require fairly decently spec'ed user end hardware to work with to either real time encode a video format in a browser engine or just either short video clips on old hardware, and it's all saved and post processed. Anyway,send me a PM and we can talk some details during business hours US EST.