Simple steps to create an instagram-like Video Boomerang effect on the web
At the weekend I was playing around with a Boomerang effect video encoder, you can kinda get it working in near real-time (I'll explain later). I got it working on Chrome on Desktop, but it would never work properly on Chrome on Android. See the code here. It looks like when you use captureStream() on a <canvas> that has a relatively large resolution (1280x720 in my case) the MediaRecorder API won't be able to encode the videos and it won't error and you can't detect that it can't encode the video ahead of time.
You should be able to create and edit videos using just the web in the browser. It should be possible to provide a user-interface akin to Screenflow that lets you create an output video that combines multiple videos, images, and audio into one video that can be uploaded to services like YouTube. This post is really just a statement of intent. I am going to start the long process of working out what is and isn't available on the platform and seeing how far we can get today.
Finally you can record your screen directly on Android via JS... well 'finally' is a strong word.