From cb3351ef785b3df4bda8fe60f5272a6459c1b8b4 Mon Sep 17 00:00:00 2001
From: Rob Walch <robwalch@users.noreply.github.com>
Date: Mon, 17 Jul 2023 17:25:06 -0700
Subject: [PATCH] Use input timescale when remuxing inband captions (#5675)

Fixes #5669
---
 src/remux/mp4-remuxer.ts     |  2 +-
 src/utils/texttrack-utils.ts | 20 +++++++++++++-------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/remux/mp4-remuxer.ts b/src/remux/mp4-remuxer.ts
index 27c10e28a38..11d5e4b6dba 100644
--- a/src/remux/mp4-remuxer.ts
+++ b/src/remux/mp4-remuxer.ts
@@ -1125,7 +1125,7 @@ export function flushTextTrackUserdataCueSamples(
     // using this._initPTS and this._initDTS to calculate relative time
     sample.pts =
       normalizePts(
-        sample.pts - (initPTS.baseTime * 90000) / initPTS.timescale,
+        sample.pts - (initPTS.baseTime * inputTimeScale) / initPTS.timescale,
         timeOffset * inputTimeScale
       ) / inputTimeScale;
   }
diff --git a/src/utils/texttrack-utils.ts b/src/utils/texttrack-utils.ts
index dd64a9cc68c..1f8a944ea74 100644
--- a/src/utils/texttrack-utils.ts
+++ b/src/utils/texttrack-utils.ts
@@ -29,13 +29,19 @@ export function addCueToTrack(track: TextTrack, cue: VTTCue) {
       }
     } catch (err) {
       logger.debug(`[texttrack-utils]: ${err}`);
-      const textTrackCue = new (self.TextTrackCue as any)(
-        cue.startTime,
-        cue.endTime,
-        cue.text
-      );
-      textTrackCue.id = cue.id;
-      track.addCue(textTrackCue);
+      try {
+        const textTrackCue = new (self.TextTrackCue as any)(
+          cue.startTime,
+          cue.endTime,
+          cue.text
+        );
+        textTrackCue.id = cue.id;
+        track.addCue(textTrackCue);
+      } catch (err2) {
+        logger.debug(
+          `[texttrack-utils]: Legacy TextTrackCue fallback failed: ${err2}`
+        );
+      }
     }
   }
   if (mode === 'disabled') {