"Just" video in HTML5 is actually trivial. You just put a video in a <video> element and you're set. Maybe put multiple resolutions in and a button to switch ou

"Just" video in HTML5 is actually trivial. You just put a video in a <video> element and you're set. Maybe put multiple resolutions in and a button to switch out the src. If you want the additional compression of VP9, you can put both a WebM source and a MP4 source in the <video> element and the browser will pick the better one, no Javascript required. As an example, I think 4chan has the simplest possible user submitted video hosting possible. They don't even need an encoding pipeline, they just serve user submitted WebM files < 3MB. It works quite well. Where it becomes harder is if you want to do complex things, like slice up content in Javascript to insert ads, manually control buffering with Javascript, try to estimate bandwidth, etc. These are harder right now because the MSE API is pretty new and used by very few websites.