Edit in JSFiddle

<div class="video-bg">

    <div class="content">

        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc non ante id magna fringilla congue. Suspendisse in elementum dolor. In in enim maximus, ultricies sapien sed, dictum purus. Proin tempus risus est. Phasellus id ullamcorper tellus. Aenean ultrices id massa ut congue. Sed id hendrerit libero. Ut egestas dignissim magna ac finibus. Vestibulum feugiat justo ut lacus semper tristique. In cursus urna felis, eget molestie elit accumsan vel.</p>

        <p>Donec consequat gravida malesuada. Integer quis mattis velit. Sed ac pulvinar lectus, non tempus eros. Nullam mi arcu, ultrices eget diam ac, pellentesque consectetur ligula. Duis lacus dui, pharetra nec mollis non, lacinia vel quam. Integer dapibus urna a magna dapibus, in scelerisque nisi cursus.</p>

    </div>

    <iframe src="https://www.youtube.com/embed/6XWwwJUaXdw?modestbranding=1&autoplay=1&controls=0&loop=1&playlist=6XWwwJUaXdw"></iframe>

</div>

.video-bg {
    position: relative;
}

.video-bg .content {
    position: relative;
    z-index: 100;
    padding: 15px 0;
}

.video-bg p {
    width: 90%;
    margin: 20px auto;
    color: #FFF;
    text-shadow: 0 1px 0 #000, 0 -1px 0 #000, 1px 0 0 #000, -1px 0 0 #000;
    font-size: 15px;
    line-height: 1.15;
    font-family: sans-serif;
    font-weight: bold;
}

.video-bg iframe {
    border: 0;
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0;
    top: 0;
    z-index: 0;
}