$(document).ready(function() {
    changeVideo("video1");
    
       
});
 
 function changeVideo(id) {
     var video_content = $("#" + id);
     var video_placement = $("#mast .wrapper");
     var video_html = video_content.html();
     
     video_placement.fadeOut("fast");
     video_placement.empty();
     video_placement.html(video_html);
     video_placement.fadeIn("slow");
     
 }