diff --git a/lib/util.js b/lib/util.js
index 9f3896d..1870e11 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -128,3 +128,23 @@ exports.getHumanTime = function(ms) {
 
   return str + ms + ' ms';
 };
+
+/**
+ * Converts seconds to format hh:mm:ss
+ *
+ * @param {Number} seconds
+ * @return {String}
+ */
+exports.formatDuration = function(seconds) {
+  var parts = [];
+  parts.push(seconds % 60);
+  var minutes = Math.floor(seconds / 60);
+  if (minutes > 0) {
+    parts.push(minutes % 60)
+    var hours = Math.floor(minutes / 60);
+    if (hours > 0) {
+        parts.push(hours);
+    }
+  }
+  return parts.reverse().join(':');
+};
diff --git a/lib/youtube-dl.js b/lib/youtube-dl.js
index efa470c..e654cc8 100644
--- a/lib/youtube-dl.js
+++ b/lib/youtube-dl.js
@@ -164,23 +164,10 @@ function call(video, args1, args2, options, callback) {
  */
 function filterData(data) {
   var info = JSON.parse(data);
-  function formatDuration(duration) {
-    var parts = [];
-    parts.push(duration % 60);
-    var minutes = Math.floor(duration / 60);
-    if (minutes > 0) {
-      parts.push(minutes % 60)
-      var hours = Math.floor(minutes / 60);
-      if (hours > 0) {
-          parts.push(hours);
-      }
-    }
-    return parts.reverse().join(':');
-  }
 
   // Add and process some entries to keep backwards compatibility
   info.filename = info._filename;
-  info.duration = formatDuration(info.duration);
+  info.duration = util.formatDuration(info.duration);
   info.itag = info.format_id;
   info.resolution = info.format.split(' - ')[1];
   return info;