Don't always switch tracks in configure().

Configure should only switch tracks if the current variant can't be
played under the new configuration.

Closes #1138

Change-Id: I1acb8bdbb0c8b41252e978bd17ef52bec1095844

lib/player.js

@@ -962,19 +962,15 @@ shaka.Player.prototype.configure = function(config) {
   shaka.util.ConfigUtils.mergeConfigObjects(
       this.config_, config, this.defaultConfig_(), this.configOverrides_(), '');
 
-  // We only need to clear buffers is the user is changing a setting that we
-  // need to see reflected immediately.
-  var clearBuffer = 'restrictions' in config;
-  this.applyConfig_(clearBuffer);
+  this.applyConfig_();
 };
 
 
 /**
  * Apply config changes.
- * @param {boolean} clearBuffer
  * @private
  */
-shaka.Player.prototype.applyConfig_ = function(clearBuffer) {
+shaka.Player.prototype.applyConfig_ = function() {
   if (this.parser_) {
     this.parser_.configure(this.config_.manifest);
   }
@@ -992,10 +988,17 @@ shaka.Player.prototype.applyConfig_ = function(clearBuffer) {
       this.onError_(error);
     }
 
-    // May need to choose new streams.
-    shaka.log.debug('Choosing new streams after changing configuration');
+    // If the stream we are playing is restricted, we need to switch.
+    var activeAudio = this.streamingEngine_.getActiveAudio();
+    var activeVideo = this.streamingEngine_.getActiveVideo();
     var period = this.streamingEngine_.getCurrentPeriod();
-    this.chooseStreamsAndSwitch_(period, clearBuffer);
+    var activeVariant = shaka.util.StreamUtils.getVariantByStreams(
+        activeAudio, activeVideo, period.variants);
+    if (!activeVariant || !activeVariant.allowedByApplication ||
+        !activeVariant.allowedByKeySystem) {
+      shaka.log.debug('Choosing new streams after changing configuration');
+      this.chooseStreamsAndSwitch_(period);
+    }
   }
 
   if (this.abrManager_) {
@@ -1059,10 +1062,7 @@ shaka.Player.prototype.resetConfiguration = function() {
   // Don't call mergeConfigObjects_(), since that would not reset open-ended
   // dictionaries like drm.servers.
   this.config_ = this.defaultConfig_();
-
-  // Rather than checking if it makes sense to clear the buffers based on which
-  // values are getting reset, just clear them.
-  this.applyConfig_(true);
+  this.applyConfig_();
 };
 
 
@@ -1452,7 +1452,7 @@ shaka.Player.prototype.selectAudioLanguage = function(language, opt_role) {
   var period = this.streamingEngine_.getCurrentPeriod();
   this.currentAudioLanguage_ = language;
   this.currentVariantRole_ = opt_role || '';
-  this.chooseStreamsAndSwitch_(period, true);
+  this.chooseStreamsAndSwitch_(period);
 };
 
 
@@ -1469,7 +1469,7 @@ shaka.Player.prototype.selectTextLanguage = function(language, opt_role) {
   var period = this.streamingEngine_.getCurrentPeriod();
   this.currentTextLanguage_ = language;
   this.currentTextRole_ = opt_role || '';
-  this.chooseStreamsAndSwitch_(period, true);
+  this.chooseStreamsAndSwitch_(period);
 };
 
 
@@ -1732,7 +1732,7 @@ shaka.Player.prototype.addTextTrack = function(
         this.loadingTextStreamIds_.indexOf(stream.id), 1);
 
     shaka.log.debug('Choosing new streams after adding a text stream');
-    this.chooseStreamsAndSwitch_(period, true);
+    this.chooseStreamsAndSwitch_(period);
     this.onTracksChanged_();
 
     return {
@@ -2515,10 +2515,9 @@ shaka.Player.prototype.chooseVariant_ = function(variants) {
  * explicit language change.
  *
  * @param {!shakaExtern.Period} period
- * @param {!boolean} clearBuffer
  * @private
  */
-shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period, clearBuffer) {
+shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period) {
   goog.asserts.assert(this.config_, 'Must not be destroyed');
 
   var variants = shaka.util.StreamUtils.filterVariantsByLanguageAndRole(
@@ -2532,7 +2531,7 @@ shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period, clearBuffer) {
   var chosenVariant = this.chooseVariant_(variants);
   if (chosenVariant) {
     this.addVariantToSwitchHistory_(chosenVariant, /* fromAdaptation */ true);
-    this.switchVariant_(chosenVariant, clearBuffer);
+    this.switchVariant_(chosenVariant, true);
   }
 
   var chosenText = textStreams[0];
@@ -2932,7 +2931,7 @@ shaka.Player.prototype.onKeyStatus_ = function(keyStatusMap) {
 
   if (activeVariant && !activeVariant.allowedByKeySystem) {
     shaka.log.debug('Choosing new streams after key status changed');
-    this.chooseStreamsAndSwitch_(period, true);
+    this.chooseStreamsAndSwitch_(period);
   }
 
   if (tracksChanged)

test/player_unit.js

@@ -854,38 +854,22 @@ describe('Player', function() {
       .then(done);
     });
 
-    it('does not clear buffers when restrictions change', function(done) {
-      var smallBandwidth = 200000;
-      var largeBandwidth = 1000000;
-
-      var smallDelay = 0.5;
-      var doNotClear = false;
-
-      var smallBandwidthSettings = {
-        abr: {restrictions: {maxBandwidth: smallBandwidth}}
-      };
-
-      var largeBandwidthSettings = {
-        abr: {restrictions: {maxBandwidth: largeBandwidth}}
-      };
-
+    it('does not switch for plain configuration changes', function(done) {
       var parser = new shaka.test.FakeManifestParser(manifest);
       var factory = function() { return parser; };
 
       var switchVariantSpy = spyOn(player, 'switchVariant_');
 
-      player.configure(smallBandwidthSettings);
-
       player.load('', 0, factory)
           .then(function() {
-            player.configure(largeBandwidthSettings);
+            player.configure({abr: {enabled: false}});
+            player.configure({streaming: {bufferingGoal: 9001}});
+
             // Delay to ensure that the switch would have been called.
-            return shaka.test.Util.delay(smallDelay);
+            return shaka.test.Util.delay(0.1);
           })
           .then(function() {
-            expect(switchVariantSpy).toHaveBeenCalledWith(
-                /* variant */ jasmine.anything(),
-                doNotClear);
+            expect(switchVariantSpy).not.toHaveBeenCalled();
           })
           .catch(fail)
           .then(done);