Here’s a hacky zoom-enable.js that enables zooming for videos on web, mobile web, and in the mobile app.
On desktop, you can use the mouse wheel to zoom in/out, and click-and-drag to reposition the zoomed in video.
On mobile (both web and in the app), you can use the pinch gesture to zoom in/out, and touch-and-drag to reposition the zoomed in video.
https://gist.github.com/olegbl/34e890b2a5e3ae73ed15ad150973fdbe