Don't replace PresentationTimeline on MPD update

Only update segment availability duration. Issue #295 Change-Id: Ia73338be4c308169f28f5394c9d4ef5dbc8af304
shaka-project · Mar 31, 2016 · 0b4398f · 0b4398f
1 parent 13a5f41
commit 0b4398f
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Showing 3 changed files with 70 additions and 26 deletions.
diff --git a/lib/dash/dash_parser.js b/lib/dash/dash_parser.js
@@ -437,40 +437,43 @@ shaka.dash.DashParser.prototype.parseManifest_ =
     if (!this.networkingEngine_)
       return;
 
+    // Determine |segmentAvailabilityDuration|.
     if (presentationStartTime == null) {
       // If this is not live, then ignore segment availability.
       segmentAvailabilityDuration = null;
+    } else if (segmentAvailabilityDuration == null) {
+      // If there is no availability given and it's live, then the segments
+      // will always be available.
+      segmentAvailabilityDuration = Number.POSITIVE_INFINITY;
+    }
+
+    if (this.manifest_) {
+      this.manifest_.presentationTimeline.setSegmentAvailabiliyDuration(
+          segmentAvailabilityDuration);
     } else {
-      if (segmentAvailabilityDuration == null) {
-        // If there is no availability given and it's live, then the segments
-        // will always be available.
-        segmentAvailabilityDuration = Number.POSITIVE_INFINITY;
+      if (presentationStartTime != null) {
+        // Offset the start time by @suggestedPresentationDelay.  This has the
+        // effect of making the segments become available later than they
+        // actually are, so it causes a delay.  Note that the DASH spec
+        // recommends that a default @suggestedPresentationDelay be used when
+        // one is not explicitly specified.
+        presentationStartTime +=
+            suggestedDelay != null ?
+            suggestedDelay :
+            shaka.dash.DashParser.DEFAULT_SUGGESTED_PRESENTATION_DELAY_;
       }
 
-      // Offset the start time by @suggestedPresentationDelay.  This has the
-      // effect of making the segments become available later than they
-      // actually are, so it causes a delay.  Note that the DASH spec
-      // recommends that a default @suggestedPresentationDelay be used when one
-      // is not explicitly specified.
-      presentationStartTime +=
-          suggestedDelay != null ?
-          suggestedDelay :
-          shaka.dash.DashParser.DEFAULT_SUGGESTED_PRESENTATION_DELAY_;
-    }
+      shaka.log.v1('maxSegmentDuration:',
+                   'explict=' + maxSegmentDuration,
+                   'derived=' + context.maxSegmentDuration);
 
-    shaka.log.v1('maxSegmentDuration:',
-                 'explict=' + maxSegmentDuration,
-                 'derived=' + context.maxSegmentDuration);
-    var timeline = new shaka.media.PresentationTimeline(
-        duration || Number.POSITIVE_INFINITY,
-        presentationStartTime,
-        segmentAvailabilityDuration,
-        maxSegmentDuration || context.maxSegmentDuration,
-        offset);
+      var timeline = new shaka.media.PresentationTimeline(
+          duration || Number.POSITIVE_INFINITY,
+          presentationStartTime,
+          segmentAvailabilityDuration,
+          maxSegmentDuration || context.maxSegmentDuration,
+          offset);
 
-    if (this.manifest_) {
-      this.manifest_.presentationTimeline = timeline;
-    } else {
       this.manifest_ = {
         periods: periods,
         presentationTimeline: timeline,

diff --git a/lib/media/presentation_timeline.js b/lib/media/presentation_timeline.js
@@ -106,6 +106,25 @@ shaka.media.PresentationTimeline.prototype.getSegmentAvailabilityDuration =
 };
 
 
+/**
+ * Updates the presentation's segment availability duration. The segment
+ * availability duration can only be updated for live.
+ *
+ * @param {?number} segmentAvailabilityDuration The presentation's new segment
+ *     availability duration in seconds.
+ */
+shaka.media.PresentationTimeline.prototype.setSegmentAvailabiliyDuration =
+    function(segmentAvailabilityDuration) {
+  goog.asserts.assert(
+      (this.segmentAvailabilityDuration_ == null &&
+       segmentAvailabilityDuration == null) ||
+      (this.segmentAvailabilityDuration_ != null &&
+       segmentAvailabilityDuration != null),
+      'Segment availability duration can only be updated for live');
+  this.segmentAvailabilityDuration_ = segmentAvailabilityDuration;
+};
+
+
 /**
  * Gets the presentation's current segment availability start time. Segments
  * ending at or before this time should be assumed to be unavailable.

diff --git a/test/presentation_timeline_unit.js b/test/presentation_timeline_unit.js
@@ -250,6 +250,28 @@ describe('PresentationTimeline', function() {
         Number.POSITIVE_INFINITY);
   });
 
+  it('setSegmentAvailabiliyDuration', function() {
+    setElapsed(0);
+    var timeline = new shaka.media.PresentationTimeline(60, null, null, 10, 0);
+    expect(timeline.getSegmentAvailabilityDuration()).toBeNull();
+
+    timeline = new shaka.media.PresentationTimeline(
+        Number.POSITIVE_INFINITY, Date.now() / 1000.0, 20, 10, 0);
+    timeline.setSegmentAvailabiliyDuration(7);
+    expect(timeline.getSegmentAvailabilityDuration()).toBe(7);
+
+    timeline = new shaka.media.PresentationTimeline(
+        Number.POSITIVE_INFINITY, Date.now() / 1000.0, 20, 10, 0);
+    timeline.setSegmentAvailabiliyDuration(Number.POSITIVE_INFINITY);
+    expect(timeline.getSegmentAvailabilityDuration()).toBe(
+        Number.POSITIVE_INFINITY);
+
+    timeline = new shaka.media.PresentationTimeline(
+        60, null, null, 10, 0);
+    timeline.setSegmentAvailabiliyDuration(null);
+    expect(timeline.getSegmentAvailabilityDuration()).toBe(null);
+  });
+
   it('clockOffset', function() {
     // setElapsed sets the local clock.  The server is 10 seconds ahead so it
     // should return 10.