HTML5 Video Autoplay not working correctly

Question

Im using this code:

Answer 1

html {
  padding: 20px 0;
  background-color: #efefef;
}

body {
  width: 400px;
  padding: 40px;
  margin: 0 auto;
  background: #fff;
  box-shadow: 1px 1px 5px rgba(0, 0, 0, 0.5);
}

video {
  width: 400px;
  display: block;
}

<video onloadeddata="this.play();this.muted=false;" poster="https://durian.blender.org/wp-content/themes/durian/images/void.png" playsinline loop muted controls>
    <source src="http://grochtdreis.de/fuer-jsfiddle/video/sintel_trailer-480.mp4" type="video/mp4" />
    Your browser does not support the video tag or the file format of this video.
</video>