Нужно разобрать скрипт

 var resize = function() {
            var width = $(window).width(),
                pWidth, // player width, to be defined
                height = $(window).height(),
                pHeight, // player height, tbd
                $tubularPlayer = $('#tubular-player');
 
            // when screen aspect ratio differs from video, video must center and underlay one dimension
 
            if (width / options.ratio < height) { // if new video height < window height (gap underneath)
                pWidth = Math.ceil(height * options.ratio); // get new player width
                $tubularPlayer.width(pWidth).height(height).css({left: (width - pWidth) / 2, top: 0}); // player width is greater, offset left; reset top
            } else { // new video width < window width (gap to right)
                pHeight = Math.ceil(width / options.ratio); // get new player height
                $tubularPlayer.width(width).height(pHeight).css({left: 0, top: (height - pHeight) / 2}); // player height is greater, offset top; reset left
            }
 
        }
 
        // events
        $(window).on('resize.tubular', function() {
            resize();
        })