.wh-video
{
  position:relative;
  width:100%;
}
.wh-video:after
{
  display:block;
  content: '';
}
.wh-video.aspect_16_9:after
{
  padding-top:56.25%;
}
.wh-video.aspect_4_3:after
{
  padding-top:56.25%;
}
.wh-video > iframe
{
  position:absolute;
  width:100%;
  height:100%;
}