[html] use video as background for div

I would like to use a video as background in CSS3. I know that there is no background-video property, but is it possible to do this behavior. Using a fullsize video-tag doesn't give the wanted result, cause there is content that need to be displayed over the video.

It need to be non JS. If it is not possible then I need to do changes on my serverside an give as result also a screenshot of the video.

I need the video to replace the colored boxes:

The colored boxes are atm just, CSS boxes.

Pure CSS method

It is possible to center a video inside an element just like a cover sized background-image without JS using the object-fit attribute or CSS Transforms.

2021 answer: object-fit

As pointed in the comments, it is possible to achieve the same result without CSS transform, but using object-fit, which I think it's an even better option for the same result:

.video-container {
    height: 300px;
    width: 300px;
    position: relative;
}

.video-container video {
  width: 100%;
  height: 100%;
  position: absolute;
  object-fit: cover;
  z-index: 0;
}

/* Just styling the content of the div, the *magic* in the previous rules */
.video-container .caption {
  z-index: 1;
  position: relative;
  text-align: center;
  color: #dc0000;
  padding: 10px;
}

<div class="video-container">
    <video autoplay muted loop>
        <source src="https://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4" type="video/mp4" />
    </video>
    <div class="caption">
      <h2>Your caption here</h2>
    </div>
</div>

Previous answer: CSS Transform

You can set a video as a background to any HTML element easily thanks to transform CSS property.

Note that you can use the transform technique to center vertically and horizontally any HTML element.

.video-container {
  height: 300px;
  width: 300px;
  overflow: hidden;
  position: relative;
}

.video-container video {
  min-width: 100%;
  min-height: 100%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translateX(-50%) translateY(-50%);
}

/* Just styling the content of the div, the *magic* in the previous rules */
.video-container .caption {
  z-index: 1;
  position: relative;
  text-align: center;
  color: #dc0000;
  padding: 10px;
}

<div class="video-container">
  <video autoplay muted loop>
    <source src="https://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4" type="video/mp4" />
  </video>
  <div class="caption">
    <h2>Your caption here</h2>
  </div>
</div>

I believe this is what you're looking for. It automatically scaled the video to fit the container.

DEMO: http://jsfiddle.net/t8qhgxuy/

Video need to have height and width always set to 100% of the parent.

HTML:

<div class="one"> CONTENT OVER VIDEO
    <video class="video-background" no-controls autoplay src="https://dl.dropboxusercontent.com/u/8974822/cloud-troopers-video.mp4" poster="http://thumb.multicastmedia.com/thumbs/aid/w/h/t1351705158/1571585.jpg"></video>
</div>

<div class="two">
    <video class="video-background" no-controls autoplay src="https://dl.dropboxusercontent.com/u/8974822/cloud-troopers-video.mp4" poster="http://thumb.multicastmedia.com/thumbs/aid/w/h/t1351705158/1571585.jpg"></video> CONTENT OVER VIDEO
</div>

CSS:

body {
    overflow: scroll;
    padding:  60px 20px;
}

.one {
    width: 90%;
    height: 30vw;
    overflow: hidden;
    border: 15px solid red;
    margin-bottom: 40px;
    position: relative;
}

.two{
    width: 30%;
    height: 300px;
    overflow: hidden;
    border: 15px solid blue;
    position: relative;
}

.video-background { /* class name used in javascript too */
    width: 100%; /* width needs to be set to 100% */
    height: 100%; /* height needs to be set to 100% */
    position: absolute;
    left: 0;
    top: 0;
    z-index: -1;
}

JS:

function scaleToFill() {
    $('video.video-background').each(function(index, videoTag) {
       var $video = $(videoTag),
           videoRatio = videoTag.videoWidth / videoTag.videoHeight,
           tagRatio = $video.width() / $video.height(),
           val;

       if (videoRatio < tagRatio) {
           val = tagRatio / videoRatio * 1.02; <!-- size increased by 2% because value is not fine enough and sometimes leaves a couple of white pixels at the edges -->
       } else if (tagRatio < videoRatio) {
           val = videoRatio / tagRatio * 1.02;
       }

       $video.css('transform','scale(' + val  + ',' + val + ')');

    });    
}

$(function () {
    scaleToFill();

    $('.video-background').on('loadeddata', scaleToFill);

    $(window).resize(function() {
        scaleToFill();
    });
});