pauseOnClose.js

jQuery(document).ready(function(){
    $('.close-reveal-modal').on("click", function(e){
        e.preventDefault();
        for (var i=0; i<window.player.length; i++){
            window.player[i].pauseVideo();
        }
    });
});

ytapi.js

function onYouTubePlayerAPIReady(){
    var videos = jQuery('.youtube-player'),
        l = videos.length;
    window.players = [];
    for (var i=0; i < l; i++){
        window.players.push(new YT.Player(videos[i].id, {
            events: {
            }
        }));
    }
}