Do not allow seeking/startup at duration

Seeking to or starting playback at the duration does not work well
across browsers.  Any seek or startup time at or past the duration of
VOD or IPR content will be bumped back by a configurable amount
(default 1s).

Closes #1014
Bug: 69874888

Change-Id: I6d21ecd8e211f0f823a093b8eb8b95d329b4385f

externs/shaka/player.js

@@ -558,7 +558,8 @@ shakaExtern.ManifestConfiguration;
  *   ignoreTextStreamFailures: boolean,
  *   startAtSegmentBoundary: boolean,
  *   smallGapLimit: number,
- *   jumpLargeGaps: boolean
+ *   jumpLargeGaps: boolean,
+ *   durationBackoff: number
  * }}
  *
  * @description
@@ -599,6 +600,12 @@ shakaExtern.ManifestConfiguration;
  *   raised first.  Then, if the app doesn't call preventDefault() on the event,
  *   the Player will jump the gap.  If false, then the event will be raised,
  *   but the gap will not be jumped.
+ * @property {number} durationBackoff
+ *   By default, we will not allow seeking to exactly the duration of a
+ *   presentation.  This field is the number of seconds before duration we will
+ *   seek to when the user tries to seek to or start playback at the duration.
+ *   To disable this behavior, the config can be set to 0.  We recommend using
+ *   the default value unless you have a good reason not to.
  * @exportDoc
  */
 shakaExtern.StreamingConfiguration;

lib/media/playhead.js

@@ -66,7 +66,8 @@ shaka.media.Playhead = function(
    * automatically be calculated later.
    * @private {?number}
    */
-  this.startTime_ = startTime;
+  this.startTime_ = startTime == null ? null :
+                    this.clampSeekToDuration_(startTime);
 
   /** @private {?function()} */
   this.onSeek_ = onSeek;
@@ -186,7 +187,12 @@ shaka.media.Playhead.prototype.destroy = function() {
 };
 
 
-/** @param {number} startTime */
+/**
+ * Adjust the start time.  Used by Player to implement the
+ * streaming.startAtSegmentBoundary configuration.
+ *
+ * @param {number} startTime
+ */
 shaka.media.Playhead.prototype.setStartTime = function(startTime) {
   if (this.video_.readyState > 0)
     this.video_.currentTime = this.clampTime_(startTime);
@@ -195,6 +201,31 @@ shaka.media.Playhead.prototype.setStartTime = function(startTime) {
 };
 
 
+/**
+ * Clamp seek times and playback start times so that we never seek to the
+ * presentation duration.  Seeking to or starting at duration does not work
+ * consistently across browsers.
+ *
+ * TODO: Clean up and simplify Playhead.  There are too many layers of, methods
+ * for, and conditions on timestamp adjustment.
+ *
+ * @see https://github.com/google/shaka-player/issues/979
+ * @param {number} time
+ * @return {number} The adjusted seek time.
+ * @private
+ */
+shaka.media.Playhead.prototype.clampSeekToDuration_ = function(time) {
+  var timeline = this.manifest_.presentationTimeline;
+  var duration = timeline.getDuration();
+  if (time >= duration) {
+    goog.asserts.assert(this.config_.durationBackoff >= 0,
+                        'Duration backoff must be non-negative!');
+    return duration - this.config_.durationBackoff;
+  }
+  return time;
+};
+
+
 /**
  * Gets the playhead's current (logical) position.
  *
@@ -245,7 +276,7 @@ shaka.media.Playhead.prototype.getStartTime_ = function() {
   // a drifting stream, this is very bad, as we will never fall back into a
   // playable range.
   // TODO: re-evaluate after #999 (drift tolerance refactor) is resolved
-  this.startTime_ = startTime;
+  this.startTime_ = this.clampSeekToDuration_(startTime);
 
   return startTime;
 };
@@ -584,6 +615,7 @@ shaka.media.Playhead.prototype.reposition_ = function(currentTime) {
   var timeline = this.manifest_.presentationTimeline;
   var start = timeline.getSafeAvailabilityStart(0);
   var end = timeline.getSegmentAvailabilityEnd();
+  var duration = timeline.getDuration();
 
   // With live content, the beginning of the availability window is moving
   // forward.  This means we cannot seek to it since we will "fall" outside the
@@ -602,6 +634,11 @@ shaka.media.Playhead.prototype.reposition_ = function(currentTime) {
   var seekSafe = timeline.getSafeAvailabilityStart(rebufferingGoal + 5);
 
 
+  if (currentTime >= duration) {
+    shaka.log.v1('Playhead past duration.');
+    return this.clampSeekToDuration_(currentTime);
+  }
+
   if (currentTime > end) {
     shaka.log.v1('Playhead past end.');
     return end;

lib/player.js

@@ -1996,7 +1996,8 @@ shaka.Player.prototype.defaultConfig_ = function() {
       ignoreTextStreamFailures: false,
       startAtSegmentBoundary: false,
       smallGapLimit: 0.5,
-      jumpLargeGaps: false
+      jumpLargeGaps: false,
+      durationBackoff: 1
     },
     abrFactory: shaka.abr.SimpleAbrManager,
     textDisplayFactory: function(videoElement) {

test/media/playhead_observer_unit.js

@@ -77,7 +77,8 @@ describe('PlayheadObserver', function() {
       useRelativeCueTimestamps: false,
       startAtSegmentBoundary: false,
       smallGapLimit: 0.5,
-      jumpLargeGaps: false
+      jumpLargeGaps: false,
+      durationBackoff: 1
     };
 
     onBuffering = jasmine.createSpy('onBuffering');

test/media/playhead_unit.js

@@ -137,10 +137,10 @@ describe('Playhead', function() {
     timeline.isLive.and.returnValue(false);
     timeline.getSegmentAvailabilityStart.and.returnValue(5);
     timeline.getSegmentAvailabilityEnd.and.returnValue(60);
+    timeline.getDuration.and.returnValue(60);
 
     // These tests should not cause these methods to be invoked.
     timeline.getSegmentAvailabilityDuration.and.throwError(new Error());
-    timeline.getDuration.and.throwError(new Error());
     timeline.setDuration.and.throwError(new Error());
 
     manifest = {
@@ -160,7 +160,8 @@ describe('Playhead', function() {
       useRelativeCueTimestamps: false,
       startAtSegmentBoundary: false,
       smallGapLimit: 0.5,
-      jumpLargeGaps: false
+      jumpLargeGaps: false,
+      durationBackoff: 1
     };
   });
 
@@ -262,6 +263,22 @@ describe('Playhead', function() {
       expect(playhead.getTime()).toBe(0);
     });
 
+    it('bumps startTime back from duration', function() {
+      video.readyState = HTMLMediaElement.HAVE_METADATA;
+      timeline.isLive.and.returnValue(false);
+      timeline.getSegmentAvailabilityStart.and.returnValue(0);
+      timeline.getSegmentAvailabilityEnd.and.returnValue(60);
+      timeline.getSeekRangeEnd.and.returnValue(60);
+      timeline.getDuration.and.returnValue(60);
+
+      playhead = new shaka.media.Playhead(
+          video, manifest, config, 60 /* startTime */, Util.spyFunc(onSeek),
+          Util.spyFunc(onEvent));
+
+      expect(playhead.getTime()).toBe(59);  // duration - durationBackoff
+      expect(video.currentTime).toBe(59);  // duration - durationBackoff
+    });
+
     it('respects a seek before metadata is loaded', function() {
       playhead = new shaka.media.Playhead(
           video,
@@ -358,6 +375,7 @@ describe('Playhead', function() {
     video.buffered = createFakeBuffered([{start: 25, end: 55}]);
 
     timeline.isLive.and.returnValue(true);
+    timeline.getDuration.and.returnValue(Infinity);
     timeline.getSegmentAvailabilityStart.and.returnValue(5);
     timeline.getSegmentAvailabilityEnd.and.returnValue(60);
     timeline.getSegmentAvailabilityDuration.and.returnValue(30);
@@ -499,6 +517,7 @@ describe('Playhead', function() {
     timeline.getSegmentAvailabilityStart.and.returnValue(5);
     timeline.getSafeAvailabilityStart.and.returnValue(5);
     timeline.getSegmentAvailabilityEnd.and.returnValue(60);
+    timeline.getDuration.and.returnValue(60);
     timeline.getSegmentAvailabilityDuration.and.returnValue(null);
 
     playhead = new shaka.media.Playhead(
@@ -516,8 +535,8 @@ describe('Playhead', function() {
     // Seek past end.
     video.currentTime = 120;
     video.on['seeking']();
-    expect(video.currentTime).toBe(60);
-    expect(playhead.getTime()).toBe(60);
+    expect(video.currentTime).toBe(59);  // duration - durationBackoff
+    expect(playhead.getTime()).toBe(59);  // duration - durationBackoff
     expect(onSeek).not.toHaveBeenCalled();
     video.on['seeking']();
     expect(onSeek).toHaveBeenCalled();
@@ -539,6 +558,7 @@ describe('Playhead', function() {
     video.readyState = HTMLMediaElement.HAVE_METADATA;
 
     timeline.isLive.and.returnValue(true);
+    timeline.getDuration.and.returnValue(Infinity);
     timeline.getSegmentAvailabilityStart.and.returnValue(1000);
     timeline.getSegmentAvailabilityEnd.and.returnValue(1000);
     timeline.getSegmentAvailabilityDuration.and.returnValue(1000);
@@ -572,6 +592,7 @@ describe('Playhead', function() {
 
     it('(live case)', function() {
       timeline.isLive.and.returnValue(true);
+      timeline.getDuration.and.returnValue(Infinity);
       timeline.getSegmentAvailabilityStart.and.returnValue(5);
       timeline.getSegmentAvailabilityEnd.and.returnValue(60);
       timeline.getSegmentAvailabilityDuration.and.returnValue(30);
@@ -607,6 +628,7 @@ describe('Playhead', function() {
       timeline.getSegmentAvailabilityStart.and.returnValue(5);
       timeline.getSafeAvailabilityStart.and.returnValue(5);
       timeline.getSegmentAvailabilityEnd.and.returnValue(60);
+      timeline.getDuration.and.returnValue(60);
       timeline.getSegmentAvailabilityDuration.and.returnValue(30);
 
       playhead = new shaka.media.Playhead(
@@ -641,6 +663,7 @@ describe('Playhead', function() {
       timeline.getSafeAvailabilityStart.and.returnValue(0);
       timeline.getSegmentAvailabilityStart.and.returnValue(0);
       timeline.getSegmentAvailabilityEnd.and.returnValue(60);
+      timeline.getDuration.and.returnValue(60);
 
       config.smallGapLimit = 1;
     });

test/media/streaming_engine_integration.js

@@ -90,7 +90,8 @@ describe('StreamingEngine', function() {
       useRelativeCueTimestamps: false,
       startAtSegmentBoundary: false,
       smallGapLimit: 0.5,
-      jumpLargeGaps: false
+      jumpLargeGaps: false,
+      durationBackoff: 1
     };
 
     onChooseStreams = jasmine.createSpy('onChooseStreams');

test/media/streaming_engine_unit.js

@@ -449,7 +449,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
     }
 
@@ -1792,7 +1793,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: true,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
       createStreamingEngine(config);
 
@@ -1829,7 +1831,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
       createStreamingEngine(config);
 
@@ -1873,7 +1876,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
       createStreamingEngine(config);
 
@@ -1919,7 +1923,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
       createStreamingEngine(config);
 
@@ -1971,7 +1976,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
       createStreamingEngine(config);
 
@@ -2128,7 +2134,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
 
       mediaSourceEngine = new shaka.test.FakeMediaSourceEngine(segmentData);
@@ -2216,7 +2223,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
 
       mediaSourceEngine = new shaka.test.FakeMediaSourceEngine(segmentData);
@@ -2286,7 +2294,8 @@ describe('StreamingEngine', function() {
         ignoreTextStreamFailures: false,
         startAtSegmentBoundary: false,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       };
 
       mediaSourceEngine = new shaka.test.FakeMediaSourceEngine(segmentData);
@@ -2475,7 +2484,8 @@ describe('StreamingEngine', function() {
         rebufferingGoal: 1,
         bufferingGoal: 1,
         smallGapLimit: 0.5,
-        jumpLargeGaps: false
+        jumpLargeGaps: false,
+        durationBackoff: 1
       });
 
       playhead.getTime.and.returnValue(0);