Separate text parsing and display logic.

Closes #796.
Closes #923.

Change-Id: Ifc2017b40a0fb570103f0fed7bc130aa24819e9f

build/types/text

@@ -1,6 +1,8 @@
-# All standard text parsing plugins.
+# All files related to text parsing and displaying.
 
++../../lib/text/cue.js
 +../../lib/text/mp4_ttml_parser.js
 +../../lib/text/mp4_vtt_parser.js
++../../lib/text/simple_text_displayer.js
 +../../lib/text/ttml_text_parser.js
 +../../lib/text/vtt_text_parser.js

externs/shaka/player.js

@@ -606,7 +606,8 @@ shakaExtern.AbrConfiguration;
  *   preferredTextLanguage: string,
  *   restrictions: shakaExtern.Restrictions,
  *   playRangeStart: number,
- *   playRangeEnd: number
+ *   playRangeEnd: number,
+ *   textDisplayFactory: shakaExtern.TextDisplayer.Factory
  * }}
  *
  * @property {shakaExtern.DrmConfiguration} drm
@@ -637,6 +638,8 @@ shakaExtern.AbrConfiguration;
  * @property {number} playRangeEnd
  *   Optional playback and seek end time in seconds. Defaults to the end of
  *   the presentation if not provided.
+ * @property {shakaExtern.TextDisplayer.Factory} textDisplayFactory
+ *   A factory to construct text displayer.
  * @exportDoc
  */
 shakaExtern.PlayerConfiguration;

externs/shaka/text.js

@@ -70,7 +70,7 @@ shakaExtern.TextParser.prototype.parseInit = function(data) {};
  * @param {shakaExtern.TextParser.TimeContext} timeContext
  *    The time information that should be used to adjust the times values
  *    for each cue.
- * @return {!Array.<!TextTrackCue>}
+ * @return {!Array.<!shaka.text.Cue>}
  *
  * @exportDoc
  */
@@ -81,3 +81,66 @@ shakaExtern.TextParser.prototype.parseMedia = function(data, timeContext) {};
  * @typedef {function(new:shakaExtern.TextParser)}
  */
 shakaExtern.TextParserPlugin;
+
+
+
+/**
+ * An interface for plugins that display text.
+ *
+ * @interface
+ * @extends {shaka.util.IDestroyable}
+ * @exportDoc
+ */
+shakaExtern.TextDisplayer = function() {};
+
+
+/**
+ * Append given text cues to the list of cues to be displayed.
+ *
+ * @param {!Array.<!shaka.text.Cue>} cues
+ *    Text cues to be appended.
+ *
+ * @exportDoc
+ */
+shakaExtern.TextDisplayer.prototype.append = function(cues) {};
+
+
+/**
+ * Remove cues in a given time range.
+ *
+ * @param {number} start
+ * @param {number} end
+ * @return {boolean}
+ *
+ * @exportDoc
+ */
+shakaExtern.TextDisplayer.prototype.remove = function(start, end) {};
+
+
+/**
+ * Returns true if text is currently visible.
+ *
+ * @return {boolean}
+ *
+ * @exportDoc
+ */
+shakaExtern.TextDisplayer.prototype.isTextVisible = function() {};
+
+
+/**
+ * Set text visibility.
+ *
+ * @param {boolean} on
+ *
+ * @exportDoc
+ */
+shakaExtern.TextDisplayer.prototype.setTextVisibility = function(on) {};
+
+
+/**
+ * A factory for creating a TextDisplayer.
+ *
+ * @typedef {function(new:shakaExtern.TextDisplayer)}
+ * @exportDoc
+ */
+shakaExtern.TextDisplayer.Factory;

lib/media/media_source_engine.js

@@ -40,13 +40,13 @@ goog.require('shaka.util.PublicPromise');
  *   when MediaSource operations fail.
  * @param {MediaSource} mediaSource The MediaSource, which must be in the
  *   'open' state.
- * @param {TextTrack} textTrack The TextTrack to use for subtitles/captions.
+ * @param {shakaExtern.TextDisplayer} textDisplayer
  *
  * @struct
  * @constructor
  * @implements {shaka.util.IDestroyable}
  */
-shaka.media.MediaSourceEngine = function(video, mediaSource, textTrack) {
+shaka.media.MediaSourceEngine = function(video, mediaSource, textDisplayer) {
   goog.asserts.assert(mediaSource.readyState == 'open',
                       'The MediaSource should be in the \'open\' state.');
 
@@ -56,8 +56,8 @@ shaka.media.MediaSourceEngine = function(video, mediaSource, textTrack) {
   /** @private {MediaSource} */
   this.mediaSource_ = mediaSource;
 
-  /** @private {TextTrack} */
-  this.textTrack_ = textTrack;
+  /** @private {shakaExtern.TextDisplayer} */
+  this.textDisplayer_ = textDisplayer;
 
   /** @private {!Object.<shaka.util.ManifestParserUtils.ContentType,
                          SourceBuffer>} */
@@ -204,8 +204,8 @@ shaka.media.MediaSourceEngine.prototype.destroy = function() {
     this.eventManager_ = null;
     this.video_ = null;
     this.mediaSource_ = null;
-    this.textTrack_ = null;
     this.textEngine_ = null;
+    this.textDisplayer_ = null;
     this.sourceBuffers_ = {};
     if (!COMPILED) {
       for (var contentType in this.queues_) {
@@ -265,7 +265,7 @@ shaka.media.MediaSourceEngine.prototype.init = function(typeConfig) {
  */
 shaka.media.MediaSourceEngine.prototype.reinitText = function(mimeType) {
   if (!this.textEngine_) {
-    this.textEngine_ = new shaka.text.TextEngine(this.textTrack_);
+    this.textEngine_ = new shaka.text.TextEngine(this.textDisplayer_);
   }
   this.textEngine_.initParser(mimeType);
 };

lib/player.js

@@ -28,6 +28,7 @@ goog.require('shaka.media.PlayheadObserver');
 goog.require('shaka.media.SegmentReference');
 goog.require('shaka.media.StreamingEngine');
 goog.require('shaka.net.NetworkingEngine');
+goog.require('shaka.text.SimpleTextDisplayer');
 goog.require('shaka.util.CancelableChain');
 goog.require('shaka.util.ConfigUtils');
 goog.require('shaka.util.Error');
@@ -67,8 +68,8 @@ shaka.Player = function(video, opt_dependencyInjector) {
   /** @private {HTMLMediaElement} */
   this.video_ = video;
 
-  /** @private {TextTrack} */
-  this.textTrack_ = null;
+  /** @private {shakaExtern.TextDisplayer} */
+  this.textDisplayer_ = null;
 
   /** @private {shaka.util.EventManager} */
   this.eventManager_ = new shaka.util.EventManager();
@@ -207,16 +208,16 @@ shaka.Player.prototype.destroy = function() {
       this.unloadChain_,
       this.destroyStreaming_(),
       this.eventManager_ ? this.eventManager_.destroy() : null,
-      this.networkingEngine_ ? this.networkingEngine_.destroy() : null
+      this.networkingEngine_ ? this.networkingEngine_.destroy() : null,
+      this.textDisplayer_ ? this.textDisplayer_.destroy() : null
     ]);
 
     this.video_ = null;
-    this.textTrack_ = null;
+    this.textDisplayer_ = null;
     this.eventManager_ = null;
     this.abrManager_ = null;
     this.networkingEngine_ = null;
     this.config_ = null;
-
     return p;
   }.bind(this));
 };
@@ -494,6 +495,8 @@ shaka.Player.prototype.load = function(manifestUri, opt_startTime,
     this.abrManager_ = new abrManagerFactory();
     this.abrManager_.configure(this.config_.abr);
 
+    this.textDisplayer_ = new this.config_.textDisplayFactory();
+
     goog.asserts.assert(this.networkingEngine_, 'Must not be destroyed');
     return shaka.media.ManifestParser.getFactory(
         manifestUri,
@@ -561,7 +564,6 @@ shaka.Player.prototype.load = function(manifestUri, opt_startTime,
     this.drmEngine_.configure(this.config_.drm);
     return this.drmEngine_.init(manifest, false /* isOffline */);
   }.bind(this)).then(function() {
-
     // Re-filter the manifest after DRM has been initialized.
     this.manifest_.periods.forEach(this.filterPeriod_.bind(this));
 
@@ -604,7 +606,6 @@ shaka.Player.prototype.load = function(manifestUri, opt_startTime,
     ]);
   }.bind(this)).then(function() {
     this.abrManager_.init(this.switch_.bind(this));
-
     // MediaSource is open, so create the Playhead, MediaSourceEngine, and
     // StreamingEngine.
     var startTime = opt_startTime || this.config_.playRangeStart;
@@ -618,7 +619,6 @@ shaka.Player.prototype.load = function(manifestUri, opt_startTime,
     // If the content is multi-codec and the browser can play more than one of
     // them, choose codecs now before we initialize streaming.
     this.chooseCodecsAndFilterManifest_();
-
     return this.streamingEngine_.init();
   }.bind(this)).then(function() {
     if (this.config_.streaming.startAtSegmentBoundary) {
@@ -821,7 +821,7 @@ shaka.Player.prototype.createMediaSource = function() {
  */
 shaka.Player.prototype.createMediaSourceEngine = function() {
   return new shaka.media.MediaSourceEngine(
-      this.video_, this.mediaSource_, this.textTrack_);
+      this.video_, this.mediaSource_, this.textDisplayer_);
 };
 
 
@@ -1432,7 +1432,7 @@ shaka.Player.prototype.selectTextLanguage = function(language, opt_role) {
  * @export
  */
 shaka.Player.prototype.isTextTrackVisible = function() {
-  return this.textTrack_.mode == 'showing';
+  return this.textDisplayer_.isTextVisible();
 };
 
 
@@ -1443,7 +1443,7 @@ shaka.Player.prototype.isTextTrackVisible = function() {
  * @export
  */
 shaka.Player.prototype.setTextTrackVisibility = function(on) {
-  this.textTrack_.mode = on ? 'showing' : 'hidden';
+  this.textDisplayer_.setTextVisibility(on);
   this.onTextTrackVisibility_();
 };
 
@@ -1662,30 +1662,6 @@ shaka.Player.prototype.initialize_ = function() {
   // Start the (potentially slow) process of opening MediaSource now.
   this.mediaSourceOpen_ = this.createMediaSource();
 
-  // If the video element has TextTracks, disable them.  If we see one that
-  // was created by a previous instance of Shaka Player, reuse it.
-  for (var i = 0; i < this.video_.textTracks.length; ++i) {
-    var track = this.video_.textTracks[i];
-    track.mode = 'disabled';
-
-    if (track.label == shaka.Player.TextTrackLabel_) {
-      this.textTrack_ = track;
-    }
-  }
-
-  if (!this.textTrack_) {
-    // As far as I can tell, there is no observable difference between setting
-    // kind to 'subtitles' or 'captions' when creating the TextTrack object.
-    // The individual text tracks from the manifest will still have their own
-    // kinds which can be displayed in the app's UI.
-    this.textTrack_ = this.video_.addTextTrack(
-        'subtitles', shaka.Player.TextTrackLabel_);
-  }
-  this.textTrack_.mode = 'hidden';
-
-  // TODO: test that in all cases, the built-in CC controls in the video element
-  // are toggling our TextTrack.
-
   // Listen for video errors.
   this.eventManager_.listen(this.video_, 'error',
       this.onVideoError_.bind(this));
@@ -1831,13 +1807,6 @@ shaka.Player.prototype.resetStreaming_ = function() {
 };
 
 
-/**
- * @const {string}
- * @private
- */
-shaka.Player.TextTrackLabel_ = 'Shaka Player TextTrack';
-
-
 /**
  * @return {!Object}
  * @private
@@ -1904,6 +1873,9 @@ shaka.Player.prototype.defaultConfig_ = function() {
       jumpLargeGaps: false
     },
     abrFactory: shaka.abr.SimpleAbrManager,
+    textDisplayFactory: function(videoElement) {
+      return new shaka.text.SimpleTextDisplayer(videoElement);
+    }.bind(null, this.video_),
     abr: {
       enabled: true,
       // This is a relatively safe default, since 3G cell connections
@@ -2355,7 +2327,7 @@ shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period) {
         languageMatches[ContentType.TEXT] &&
         chosen[ContentType.TEXT].language !=
             chosen[ContentType.AUDIO].language) {
-      this.textTrack_.mode = 'showing';
+      this.textDisplayer_.setTextVisibility(true);
       this.onTextTrackVisibility_();
     }
   }