I recently came across this website Design the next iPhone where after you click preset you have an option of downloading the video of 6s. As you can see below
in the past I’ve used the spite’s ccapture.js library for recording canvas to video using a fixed framerate. It is kind of dated, and generates WebM and PNGs sequences very well.
a more modern approach would be using html5 captureStream() method to grab canvas data and then record it using the MediaRecorder API. Please see this page from mozilla docs for details