The objective is to play videos from various sources full screen with minimal clutter. It used to be possible to control advertising, logging in and other 'recommended' videos with HTML here, but all this seems to be down to the channel which is sourcing the video these days. It's slightly fiddly to get a decent appearance of the thumbnail and the video on mobile, but these examples seem to work quite well.

CERN

Recommended embedding.

Youtube

Rienzi overture, Hochschule für Musik FRANZ LISZT, Weimar

Vimeo