Alas, this flag only prevents video that has sound from auto-playing. It’s the inadequate option that my earlier comment was referring to.

Here’s more: https://www.chromium.org/audio-video/autoplay

https://developers.google.com/web/updates/2017/09/autoplay-p...

Quoting the blog post, Google’s decision that ”Muted autoplay is always allowed” is the problem. If any other Chrome users wondered why videos now auto-play without sound (even with this option set), at least based on the relatively minimal docs about this flag, this is why.