Hi @ns23, when using background video, the video will never resize smaller than the smallest physical dimension, the background video works like a background image set to cover.
The video in question is 1280px wide, so the minimum size to show the full video contents using the background video will be 1280 and currently you are using it in a 940px container.
One solution is to use a tool like handbreak.fr to resize the video to 940px wide so that it shows on desktop (will still crop on mobile)
Second solution would be not to use a background video widget, but instead use a custom html video embed, which will allow you to style the embed responsively, see here: [Tutorial] Responsive Video using HTML Embed
When the size of the background video widget goes below the actual physical size of the video, the video will zoom/crop.
I hope this helps.