From d8aa24f41d79c9efb58014c3069c5183738f26d4 Mon Sep 17 00:00:00 2001
From: Dave Nicholas <davenicholasuk@gmail.com>
Date: Thu, 16 Nov 2023 08:48:12 +0000
Subject: [PATCH] fix(DASH): Segments being fetched out of the range of the
 timeline (#5889)

Fixes: https://github.com/shaka-project/shaka-player/issues/3952
---
 .gitignore                         | 1 +
 lib/dash/mpd_utils.js              | 6 ++++--
 lib/dash/segment_template.js       | 2 +-
 lib/media/presentation_timeline.js | 5 ++++-
 test/dash/mpd_utils_unit.js        | 3 ++-
 5 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/.gitignore b/.gitignore
index e67fa224bc..cf5683caa1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ coverage/
 .DS_Store
 .vscode
 .babel-cache
+.idea/
diff --git a/lib/dash/mpd_utils.js b/lib/dash/mpd_utils.js
index 252786a272..4a31dc8c46 100644
--- a/lib/dash/mpd_utils.js
+++ b/lib/dash/mpd_utils.js
@@ -128,11 +128,12 @@ shaka.dash.MpdUtils = class {
    * @param {number} unscaledPresentationTimeOffset
    * @param {number} periodDuration The Period's duration in seconds.
    *   Infinity indicates that the Period continues indefinitely.
+   * @param {number} startNumber
    * @return {!Array.<shaka.media.PresentationTimeline.TimeRange>}
    */
   static createTimeline(
       segmentTimeline, timescale, unscaledPresentationTimeOffset,
-      periodDuration) {
+      periodDuration, startNumber) {
     goog.asserts.assert(
         timescale > 0 && timescale < Infinity,
         'timescale must be a positive, finite integer');
@@ -243,6 +244,7 @@ shaka.dash.MpdUtils = class {
           end: endTime / timescale,
           unscaledStart: startTime,
           partialSegments: partialSegments,
+          segmentPosition: timeline.length + startNumber,
         };
         timeline.push(item);
 
@@ -306,7 +308,7 @@ shaka.dash.MpdUtils = class {
     if (timelineNode) {
       timeline = MpdUtils.createTimeline(
           timelineNode, timescale, unscaledPresentationTimeOffset,
-          context.periodInfo.duration || Infinity);
+          context.periodInfo.duration || Infinity, startNumber);
     }
 
     const scaledPresentationTimeOffset =
diff --git a/lib/dash/segment_template.js b/lib/dash/segment_template.js
index b43f6a7e17..b50ae26225 100644
--- a/lib/dash/segment_template.js
+++ b/lib/dash/segment_template.js
@@ -820,7 +820,7 @@ shaka.dash.TimelineSegmentIndex = class extends shaka.media.SegmentIndex {
     if (!ref) {
       const mediaTemplate = this.templateInfo_.mediaTemplate;
       const range = this.templateInfo_.timeline[correctedPosition];
-      const segmentReplacement = position + this.templateInfo_.startNumber;
+      const segmentReplacement = range.segmentPosition;
       const timeReplacement = this.templateInfo_
           .unscaledPresentationTimeOffset + range.unscaledStart;
       const timestampOffset = this.periodStart_ -
diff --git a/lib/media/presentation_timeline.js b/lib/media/presentation_timeline.js
index df1695a36d..8b8d0221c4 100644
--- a/lib/media/presentation_timeline.js
+++ b/lib/media/presentation_timeline.js
@@ -620,7 +620,8 @@ shaka.media.PresentationTimeline = class {
  *   start: number,
  *   unscaledStart: number,
  *   end: number,
- *   partialSegments: number
+ *   partialSegments: number,
+ *   segmentPosition: number
  * }}
  *
  * @description
@@ -634,6 +635,8 @@ shaka.media.PresentationTimeline = class {
  *   The end time (exclusive) of the range.
  * @property {number} partialSegments
  *   The number of partial segments
+ * @property {number} segmentPosition
+ *   The segment position of the timeline entry as it appears in the manifest
  *
  * @export
  */
diff --git a/test/dash/mpd_utils_unit.js b/test/dash/mpd_utils_unit.js
index dfedb3bb4e..9ce1ec892d 100644
--- a/test/dash/mpd_utils_unit.js
+++ b/test/dash/mpd_utils_unit.js
@@ -459,7 +459,8 @@ describe('MpdUtils', () => {
       console.assert(segmentTimeline);
 
       const timeline = MpdUtils.createTimeline(
-          segmentTimeline, timescale, presentationTimeOffset, periodDuration);
+          segmentTimeline, timescale, presentationTimeOffset,
+          periodDuration, 0);
       expect(timeline).toEqual(
           expected.map((c) => jasmine.objectContaining(c)));
     }