diff --git a/lib/media/playhead.js b/lib/media/playhead.js
index 8c37794768..9542c5bf95 100644
--- a/lib/media/playhead.js
+++ b/lib/media/playhead.js
@@ -228,7 +228,12 @@ shaka.media.Playhead.prototype.onWatchdogTimer_ = function() {
   var fudgeFactor = shaka.media.Playhead.FUDGE_FACTOR_;
   var threshold = shaka.media.Playhead.UNDERFLOW_THRESHOLD_;
 
-  var duration = this.video_.duration - fudgeFactor;
+  var duration;
+  if (this.timeline_.isLive()) {
+    duration = this.timeline_.getSegmentAvailabilityEnd() - fudgeFactor;
+  } else {
+    duration = this.video_.duration - fudgeFactor;
+  }
 
   var atEnd = (bufferEnd >= duration) || (this.video_.ended);
   if (!this.buffering_) {