<audio>
and <video>
tags without Javascript.video/mp4
<video preload="auto" controls="controls">
<source src="https://s3.amazonaws.com/x265.org/video/Tractor_500kbps_x265.mp4" type='video/mp4'>
</video>
HTMLMediaElement.canPlayType('video/mp4')
→ MediaSource.isTypeSupported('video/mp4')
→