Fullscreen background video

.video_contain {
 }
 video {
     z-index: -10;
    position: fixed;
       right: 0;
       bottom: 0;
       min-width: 100%;
       min-height: 100%;
       transform: translateX(calc((100% - 100vw) / 2));
 }
 
 .opacityOverlayBackgroundVideo {
   background: rgba(0, 0, 0, 0.50);
   left: 0;
   top: 0;
   height: 100%;
   width: 100%;
 }
<div class="vid-container video_contain">
    <video class="bgvid" autoplay="autoplay" muted="muted" preload="auto" loop="loop">
      <source src="assets/video1.mp4" type="video/mp4">
    </video>
    <div class="opacityOverlayBackgroundVideo"></div>
  </div>