gistfile1.html

<!-- XML from candy-->
  <video media-id="57519164">
    <caption>Different caption for the same video</caption>
  </video>

<!-- HTML via XSLT-->
  <video id="video-57519164"></video>

<!-- JS added into page by php from candy meta -->
  <script>
    require(['VideoHandler'], function(VideoHandler){
      VideoHandler.add({
        id: 'video-57519164',
        width: 999,
        height: 888,
        href: '',
        // etc 
      });
      VideoHandler.add({
        id: 'video-2',
        width: 999,
        height: 888,
        href: '',
        // etc 
      });
    });
  </script>

Or we could have a global object (durn dur duuurn) which describes the meta of the page (inbcluding the video)?