It is necessary that the video resolution is adjusted to the screen size. These links didn't help -

example1

<div class="header"> <div class="header__video-wrapp"> <div class="header__video-box"> <video class="header__video" id='header__video' loop autoplay> <source src="https://s3-us-west-2.amazonaws.com/coverr/mp4/Winter-Grass.mp4" type="video/mp4"> <source src="https://s3-us-west-2.amazonaws.com/coverr/mp4/Winter-Grass.mp4" type="video/webm"> </video> </div> </div> <div class='header__video-play' onclick='document.getElementById("header__video").play();'>play</div>

example2

    1 answer 1

     <video id="video">...</video> <style> #video { position: absolute; width: 100%; height: 100%; z-index: -1; } <style>