From 4ad575d50eeebafb78f68d7e25d1807fa50adc94 Mon Sep 17 00:00:00 2001
From: Rob Walch <rwalch@apple.com>
Date: Fri, 16 Feb 2024 15:43:11 -0800
Subject: [PATCH] Shift DateRange metadata Cue times when media timeline is
 shifted Fixes #6203

---
 src/controller/id3-track-controller.ts | 43 ++++++++++++++++++++------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/src/controller/id3-track-controller.ts b/src/controller/id3-track-controller.ts
index f0b89523a2d..a11ed785d6b 100644
--- a/src/controller/id3-track-controller.ts
+++ b/src/controller/id3-track-controller.ts
@@ -10,10 +10,12 @@ import {
   isDateRangeCueAttribute,
   isSCTE35Attribute,
 } from '../loader/date-range';
+import { LevelDetails } from '../loader/level-details';
 import { MetadataSchema } from '../types/demuxer';
 import type {
   BufferFlushingData,
   FragParsingMetadataData,
+  LevelPTSUpdatedData,
   LevelUpdatedData,
   MediaAttachedData,
 } from '../types/events';
@@ -95,7 +97,7 @@ class ID3TrackController implements ComponentAPI {
     this._registerListeners();
   }
 
-  destroy() {
+  public destroy() {
     this._unregisterListeners();
     this.id3Track = null;
     this.media = null;
@@ -112,6 +114,7 @@ class ID3TrackController implements ComponentAPI {
     hls.on(Events.FRAG_PARSING_METADATA, this.onFragParsingMetadata, this);
     hls.on(Events.BUFFER_FLUSHING, this.onBufferFlushing, this);
     hls.on(Events.LEVEL_UPDATED, this.onLevelUpdated, this);
+    hls.on(Events.LEVEL_PTS_UPDATED, this.onLevelPtsUpdated, this);
   }
 
   private _unregisterListeners() {
@@ -122,17 +125,18 @@ class ID3TrackController implements ComponentAPI {
     hls.off(Events.FRAG_PARSING_METADATA, this.onFragParsingMetadata, this);
     hls.off(Events.BUFFER_FLUSHING, this.onBufferFlushing, this);
     hls.off(Events.LEVEL_UPDATED, this.onLevelUpdated, this);
+    hls.off(Events.LEVEL_PTS_UPDATED, this.onLevelPtsUpdated, this);
   }
 
   // Add ID3 metatadata text track.
-  protected onMediaAttached(
+  private onMediaAttached(
     event: Events.MEDIA_ATTACHED,
     data: MediaAttachedData,
   ): void {
     this.media = data.media;
   }
 
-  protected onMediaDetaching(): void {
+  private onMediaDetaching(): void {
     if (!this.id3Track) {
       return;
     }
@@ -146,13 +150,13 @@ class ID3TrackController implements ComponentAPI {
     this.dateRangeCuesAppended = {};
   }
 
-  createTrack(media: HTMLMediaElement): TextTrack {
+  private createTrack(media: HTMLMediaElement): TextTrack {
     const track = this.getID3Track(media.textTracks) as TextTrack;
     track.mode = 'hidden';
     return track;
   }
 
-  getID3Track(textTracks: TextTrackList): TextTrack | void {
+  private getID3Track(textTracks: TextTrackList): TextTrack | void {
     if (!this.media) {
       return;
     }
@@ -169,7 +173,7 @@ class ID3TrackController implements ComponentAPI {
     return this.media.addTextTrack('metadata', 'id3');
   }
 
-  onFragParsingMetadata(
+  private onFragParsingMetadata(
     event: Events.FRAG_PARSING_METADATA,
     data: FragParsingMetadataData,
   ) {
@@ -243,7 +247,7 @@ class ID3TrackController implements ComponentAPI {
     }
   }
 
-  updateId3CueEnds(startTime: number, type: MetadataSchema) {
+  private updateId3CueEnds(startTime: number, type: MetadataSchema) {
     const cues = this.id3Track?.cues;
     if (cues) {
       for (let i = cues.length; i--; ) {
@@ -259,7 +263,7 @@ class ID3TrackController implements ComponentAPI {
     }
   }
 
-  onBufferFlushing(
+  private onBufferFlushing(
     event: Events.BUFFER_FLUSHING,
     { startOffset, endOffset, type }: BufferFlushingData,
   ) {
@@ -291,7 +295,23 @@ class ID3TrackController implements ComponentAPI {
     }
   }
 
-  onLevelUpdated(event: Events.LEVEL_UPDATED, { details }: LevelUpdatedData) {
+  private onLevelUpdated(
+    event: Events.LEVEL_UPDATED,
+    { details }: LevelUpdatedData,
+  ) {
+    this.updateDateRangeCues(details, true);
+  }
+
+  private onLevelPtsUpdated(
+    event: Events.LEVEL_PTS_UPDATED,
+    data: LevelPTSUpdatedData,
+  ) {
+    if (Math.abs(data.drift) > 0.01) {
+      this.updateDateRangeCues(data.details);
+    }
+  }
+
+  private updateDateRangeCues(details: LevelDetails, removeOldCues?: true) {
     if (
       !this.media ||
       !details.hasProgramDateTime ||
@@ -303,7 +323,7 @@ class ID3TrackController implements ComponentAPI {
     const { dateRanges } = details;
     const ids = Object.keys(dateRanges);
     // Remove cues from track not found in details.dateRanges
-    if (id3Track) {
+    if (id3Track && removeOldCues) {
       const idsToRemove = Object.keys(dateRangeCuesAppended).filter(
         (id) => !ids.includes(id),
       );
@@ -376,6 +396,9 @@ class ID3TrackController implements ComponentAPI {
         if (cue) {
           if (durationKnown && !appendedDateRangeCues.durationKnown) {
             cue.endTime = endTime;
+          } else if (Math.abs(cue.startTime - startTime) > 0.01) {
+            cue.startTime = startTime;
+            cue.endTime = endTime;
           }
         } else if (Cue) {
           let data = dateRange.attr[key];