using a video in css code example
Example: how to set background video in html
<div class="fullscreen-bg">
<video loop muted autoplay poster="img/videoframe.jpg" class="fullscreen-bg__video">
<source src="video/big_buck_bunny.webm" type="video/webm">
<source src="video/big_buck_bunny.mp4" type="video/mp4">
<source src="video/big_buck_bunny.ogv" type="video/ogg">
</video>
</div>