Responsives Video anzeigen

class="responsive-video">
<iframe width="560" height="315" src="/videos/testvideo.mp4" frameborder="0" allowfullscreen></iframe>
</div>

Und die CSS

.responsive-video {
padding-bottom: 56.25%;
position: relative;
overflow: hidden;
display: block;
height: 0;
}
.responsive-video iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}