Add player method to set playback start time ahead of downloading chunks

lib/player/http_video_source.js

@@ -52,6 +52,9 @@ shaka.player.HttpVideoSource = function(mediaUrl, textUrl, drmScheme) {
 
   /** @private {HTMLTrackElement} */
   this.textTrack_ = null;
+
+  /** @private {?number} */
+  this.playbackStartTime_ = null;
 };
 goog.inherits(shaka.player.HttpVideoSource, shaka.util.FakeEventTarget);
 
@@ -167,6 +170,13 @@ shaka.player.HttpVideoSource.prototype.enableTextTrack = function(enabled) {
 };
 
 
+/** @override */
+shaka.player.HttpVideoSource.prototype.setPlaybackStartTime =
+    function(startTime) {
+  this.playbackStartTime_ = startTime;
+};
+
+
 /** @override */
 shaka.player.HttpVideoSource.prototype.enableAdaptation = function(enabled) {
   // nop

lib/player/i_video_source.js

@@ -223,3 +223,12 @@ shaka.player.IVideoSource.prototype.isOffline = function() {};
  * @return {boolean} True if the stream is live.
  */
 shaka.player.IVideoSource.prototype.isLive = function() {};
+
+
+/**
+ * Sets time in seconds from which point video playback should begin.
+ *
+ * @param {?number} startTime
+ */
+shaka.player.IVideoSource.prototype.setPlaybackStartTime =
+    function(startTime) {};

lib/player/player.js

@@ -115,6 +115,9 @@ shaka.player.Player = function(video) {
 
   /** @private {!shaka.player.DrmSchemeInfo.Restrictions} */
   this.restrictions_ = new shaka.player.DrmSchemeInfo.Restrictions();
+
+  /** @private {?number} */
+  this.playbackStartTime_ = null;
 };
 goog.inherits(shaka.player.Player, shaka.util.FakeEventTarget);
 
@@ -269,6 +272,8 @@ shaka.player.Player.prototype.load = function(videoSource) {
                               this.onFirstTimestamp_.bind(this));
   }
 
+  videoSource.setPlaybackStartTime(this.playbackStartTime_);
+
   // Sync adaptation setting, which could have been set before this source was
   // loaded.
   videoSource.enableAdaptation(this.adaptationEnabled_);
@@ -685,6 +690,25 @@ shaka.player.Player.prototype.getRestrictions = function() {
 };
 
 
+/**
+ * @param {number} startTime The time (in seconds) you want to
+ *      set as the starting time for playback.
+ * @export
+ */
+shaka.player.Player.prototype.setPlaybackStartTime = function(startTime) {
+  this.playbackStartTime_ = startTime;
+};
+
+
+/**
+ * @return {?number} The currently set start time
+ * @export
+ */
+shaka.player.Player.prototype.getPlaybackStartTime = function() {
+  return this.playbackStartTime_;
+};
+
+
 /**
  * @return {boolean}
  * @export

lib/player/stream_video_source.js

@@ -151,6 +151,9 @@ shaka.player.StreamVideoSource = function(manifestInfo, estimator, abrManager) {
 
   /** @private {?number} */
   this.seekRangeTimer_ = null;
+
+  /** @private {?number} */
+  this.playbackStartTime_ = null;
 };
 goog.inherits(shaka.player.StreamVideoSource, shaka.util.FakeEventTarget);
 
@@ -653,6 +656,13 @@ shaka.player.StreamVideoSource.prototype.enableTextTrack = function(enabled) {
 };
 
 
+/** @override */
+shaka.player.StreamVideoSource.prototype.setPlaybackStartTime =
+    function(startTime) {
+  this.playbackStartTime_ = startTime;
+};
+
+
 /** @override */
 shaka.player.StreamVideoSource.prototype.enableAdaptation = function(enabled) {
   this.abrManager_.enable(enabled);
@@ -1113,7 +1123,15 @@ shaka.player.StreamVideoSource.prototype.startStreams_ = function(
     streamStartTime = streamLimits.end;
   } else {
     this.mediaSource.duration = streamLimits.end - streamLimits.start;
-    streamStartTime = streamLimits.start;
+    // If a specific start time was set, and it's within the
+    // stream limits, use that as the start time.
+    if (this.playbackStartTime_ &&
+        this.playbackStartTime_ <= streamLimits.end &&
+        this.playbackStartTime_ >= streamLimits.start) {
+      streamStartTime = this.playbackStartTime_;
+    } else {
+      streamStartTime = streamLimits.start;
+    }
   }
 
   // Set the video's current time before starting the streams so that the
@@ -1656,4 +1674,3 @@ shaka.player.StreamVideoSource.prototype.cancelSeekRangeTimer_ = function() {
     this.seekRangeTimer_ = null;
   }
 };
-