feat: add presentationTime as an attribute on each SegmentTemplate se…

…gment (#139)
videojs · Jul 27, 2021 · a972b8c · a972b8c
1 parent 39109d0
commit a972b8c
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Showing 11 changed files with 556 additions and 174 deletions.
diff --git a/src/segment/segmentTemplate.js b/src/segment/segmentTemplate.js
@@ -157,14 +157,25 @@ export const segmentsFromTemplate = (attributes, segmentTimeline) => {
     templateValues.Time = segment.time;
 
     const uri = constructTemplateUrl(attributes.media || '', templateValues);
+    // See DASH spec section 5.3.9.2.2
+    // - if timescale isn't present on any level, default to 1.
+    const timescale = attributes.timescale || 1;
+    // - if presentationTimeOffset isn't present on any level, default to 0
+    const presentationTimeOffset = attributes.presentationTimeOffset || 0;
+    // presentationTimeOffset has already been adjusted by the timescale
+    const presentationTime =
+      // Even if the @t attribute is not specified for the segment, segment.time is
+      // calculated in mpd-parser prior to this, so it's assumed to be available.
+      attributes.periodStart + (segment.time / timescale) - presentationTimeOffset;
 
     const map = {
       uri,
       timeline: segment.timeline,
       duration: segment.duration,
       resolvedUri: resolveUrl(attributes.baseUrl || '', uri),
       map: mapSegment,
-      number: segment.number
+      number: segment.number,
+      presentationTime
     };
 
     if (attributes.presentationTimeOffset) {