html, body {
height: 100%;
margin: 0;
padding: 0;
}
.sized {
height: 100%;
position: relative;
background: #eee;
overflow:hidden;
padding:0;
}
.sized iframe {
position:absolute;
left: 0;
top: 0;
width: 100%;
height: 100%;
}
@media (min-width: 320px) {
height: 200%;
top: -50%;
}
@media (min-width: 640px) {
height: 180%;
top: -40%;
}
<div class="sized">
<iframe src="https://player.vimeo.com/video/135335257?autoplay=false" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
</div>
<h3>Original video</h3>
<iframe src="https://player.vimeo.com/video/135335257?autoplay=false" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>