Maintains aspect ratio of widescreen video. change 'video' to be the tag, class, id, or combination of the three for element.

maintain_widescreen_aspect.js

$(function(){
    var el = $('video'),
    maintain_aspect = function(){
        el.each(function(){
            var $width = $(this).innerWidth(),
            $new_height = $width * .562;
            $(this).css({'height' : $new_height})
        })
    };
    $(window).resize(function(){
        maintain_aspect()
    })
    // on page load
    maintain_aspect()
})