diff -r 9b8e68803f6f -r 7968346b9689 src/js/widgets/sliderWidget.js
--- a/src/js/widgets/sliderWidget.js	Tue Feb 21 17:26:51 2012 +0100
+++ b/src/js/widgets/sliderWidget.js	Wed Feb 29 18:13:14 2012 +0100
@@ -52,7 +52,7 @@
   
   var time = this._Popcorn.currentTime();
 
-  var duration = this._serializer.currentMedia().meta["dc:duration"] / 1000;
+  var duration = this._serializer.getDuration() / 1000;
   var percents = time / duration;
   
   /* we do these complicated calculations to center exactly
@@ -92,7 +92,7 @@
   var width = this.sliderBackground.width();
   var relX = event.pageX - parentOffset.left;
 
-  var duration = this._serializer.currentMedia().meta["dc:duration"] / 1000;
+  var duration = this._serializer.getDuration() / 1000;
   var newTime = ((relX / width) * duration).toFixed(2);
 
   this._Popcorn.currentTime(newTime);
@@ -105,7 +105,7 @@
   var width = this.sliderBackground.width();
   var relX = event.pageX - parentOffset.left;
 
-  var duration = this._serializer.currentMedia().meta["dc:duration"] / 1000;
+  var duration = this._serializer.getDuration() / 1000;
   var newTime = ((relX / width) * duration).toFixed(2);
 
   this._Popcorn.currentTime(newTime);
@@ -161,7 +161,7 @@
   var width = this.sliderBackground.width();
   var relX = event.pageX - parentOffset.left;
 
-  var duration = this._serializer.currentMedia().meta["dc:duration"] / 1000;
+  var duration = this._serializer.getDuration() / 1000;
   var newTime = ((relX / width) * duration).toFixed(2);
 
   this._Popcorn.currentTime(newTime);