That's how autoplay videos were originally implemented on mobile browsers. Implementations included GIFs, or giant JPGs of stitched video frames switched out wi

That's how autoplay videos were originally implemented on mobile browsers. Implementations included GIFs, or giant JPGs of stitched video frames switched out with JS. Some even used video decoders that were transpiled to JS and there are webassembly versions now too. It was all replaced when browsers finally implemented video tags that played in screen, but the tech still exists.