Pinafore-Web-Client-Frontend/routes/_components/AutoplayVideo.html

<video
  class="autoplay-video {className || ''}"
  aria-label={ariaLabel || ''}
  style="background-image: url({poster});"
  {poster}
  {width}
  {height}
  {src}
  autoplay
  muted
  loop
  webkit-playsinline
  playsinline
/>
<style>
  .autoplay-video {
    background-repeat: no-repeat;
    background-position: center;
    background-size: contain;
  }
</style>