<section id="sect_sel">
    <video id="video" autoplay="autoplay" loop="loop" preload="auto" muted>
    <source src="_images/rest.mp4"></source>
    </video>          
</section>

section {
    display: block;
    width: 100%;
    height: 200px;
    overflow: hidden;
}
video {
    display: block;
    width: 100%;
}