Video speeding up

[omrivolk]

I have adapted the core of this repo to display a video on open layers. But sometimes the video just speeds up, especially when zooming. Another side effect of this is that video.currentTime gives a wrong answer. I know this because I embedded the frame number into video. I also see this happening in the online example here:
https://lcalisto.github.io/ol_videos/

I've looked around and saw that people recommend changing the setInterval for the map.render() with requestanimationframe but that didn't help.

Any idea why this is happening and how to fix?