Avoid ewma sampling from failing on 0 duration segments.

Fixes #582
shaka-project · Nov 10, 2016 · 3a64b0d · 3a64b0d
1 parent f7fd3c9
commit 3a64b0d
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/lib/abr/ewma.js b/lib/abr/ewma.js
@@ -54,7 +54,10 @@ shaka.abr.Ewma = function(halfLife) {
  */
 shaka.abr.Ewma.prototype.sample = function(weight, value) {
   var adjAlpha = Math.pow(this.alpha_, weight);
-  this.estimate_ = value * (1 - adjAlpha) + adjAlpha * this.estimate_;
+  var newEstimate = value * (1 - adjAlpha) + adjAlpha * this.estimate_;
+  // In rare circumstances newEstimate may come out to NaN. In these
+  // cases ignore it so that subsequent sampling doesn't fail.
+  this.estimate_ = newEstimate || this.estimate_;
   this.totalWeight_ += weight;
 };