Use: <video autoplay loop muted playsinline src="cats.mp4"></video> as Twitter does

About #mp4, #webm, #x264, #x265, #VP9, #VP8, #AV1 containers and codecs

Evilmartian uses the new codec and here is the comparison: "In AV1 it is just 68 KB, similar to the image file. HEVC is 195 KB, and H264 is 512 КB."

Use an image for dark mode only 😯

<picture>
  <source srcset="dark-animation.avifs" media="(prefers-color-scheme: dark)">
  <img src="light-animation.avif" alt="">
</picture>