How to build a cinematic home page with a video background

The page that talked me into this was ByteDance's launch. You open it and there is no page, just video: full-bleed, edge to edge, a fisheye shot of a guy roaring on a beach volleyball court, with the nav floating on top of it and nothing else competing. I closed the tab and went back to it twice, which is usually my signal that something is working on me. My own blog home page, meanwhile, was a…