html,body{
  height: 3000px;
  background: black;
}

video{
  position: fixed;
  top: 0;
  left: 50%;
  wdith: 50%;
  transform: translate(-50%,0);
}

h1{
  z-index: 1;
  position: relative;
  text-align: center;
  font-family: arial;
  font-size: 16px;
  color: #333333; 
}