Nr 2 Flummi, wenn du mir die Ehre erweist :3

s/item.tpl.html

@@ -63,7 +63,7 @@
   <script src="./s/videojs.persistvolume.js"></script>
   <script>
     (function() {                                               
-      var vid1 = videojs('my-video_html5_api');
+        var vid1 = videojs( document.querySelector("video") );
         vid1.persistvolume({                                  
             namespace: "f0ck"                                   
         });