The bit that matters
The still is the background. The same clip sits on top, looped and muted, at 40% opacity. If the video never loads, or reduced motion hides it, the photograph is already the hero. For a full guide on how to create this subtle background motion, check out the article Giving a Still Hero a Little Motion with a Low-Opacity Video.
<div class="relative min-h-[60vh] overflow-hidden bg-cover" style="background-image: url(background.jpg)">
<video autoplay muted loop playsinline class="absolute top-0 right-0 h-full w-full opacity-40">
<source src="smoke.mp4" type="video/mp4" />
</video>
</div>