media

images, audio, and video.

video

to embed a video in an HTML document use the video element. 3 video file formats are supported: ogg, webm, and mp4. squat w/o autoplay:

HTML video element, with the following attributes:   
<video controls autoplay loop muted playsinline>
<source src="/media/a.webm" type="video/webm"> 
<source src="/media/a.mp4" type="video/mp4"> 
</video> 

autoplay

the video element has the attribute autoplay. Tap to play/pause. on Windows Tap to select then spacebar to play/pause.

the autoplay attribute controls whether the browser downloads and plays a video immediately. The precise way it works depends on the platform and browser. The autoplay attribute does not work in mobile devices like iPad and iPhone.

device orientation

setting video max-width:100% with CSS can resolve many device orientation layout problems.

video and source developers.google.com web.dev

sintel video 52sec, and sound.

audio

the audio element is used to embed sound content in a doc.

HTML audio element  
<audio controls>
<source src="/media/a.ogg" type="audio/ogg"> 
<source src="/media/a.mp3" type="audio/mpeg"> 
</audio> 

audio developer.mozilla.org