$(function(){

if (window.isScroll) {
  $('html,body').on('mousewheel', function(){
    checkBGVideo();
  });
} else {
  $(window).on('slideChange',function(event, number, element){
    //stop all videos
    $('video').each(function(){ $(this)[0].pause();});

    //start selected
    if ($(element).hasClass('video')){
      var $el = $(element).find('.background video').eq(0);
      $el[0].play();
    }
  });
}

//toggle play/pause video
function checkBGVideo(){
  $('.slide.video').each(function(){
    var $el = $(this).find('.background video').eq(0);

    if (isElementInView($(this))) {
      $el[0].play();
    } else {
      $el[0].pause();
    }
  });
}

//is element in view?
function isElementInView(element) {
  var scrollTop = $(window).scrollTop(),
      $element = $(element),
      pageBottom = scrollTop + $(window).height(),
      elementTop = $element.offset().top,
      elementBottom = elementTop + $element.height();

  return (scrollTop > elementTop - $(window).height()) && (scrollTop < elementTop + $element.height());
};

});