From af42912e76c6a78969b795fb83d9311409c432ed Mon Sep 17 00:00:00 2001
From: Asen-O-Nikolov <98342935+Asen-O-Nikolov@users.noreply.github.com>
Date: Mon, 29 Jan 2024 20:08:50 +0200
Subject: [PATCH] fix(Remuxer): Safari segment overlap ensure PTS order (#6132)

* fix(Remuxer): Safari segment overlap ensure PTS alignment
---
 src/remux/mp4-remuxer.ts | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/remux/mp4-remuxer.ts b/src/remux/mp4-remuxer.ts
index 8e194f6a209..3dd815508de 100644
--- a/src/remux/mp4-remuxer.ts
+++ b/src/remux/mp4-remuxer.ts
@@ -544,12 +544,27 @@ export default class MP4Remuxer implements Remuxer {
             inputSamples[0].dts = firstDTS;
             inputSamples[0].pts = firstPTS;
           } else {
+            let isPTSOrderRetained = true;
             for (let i = 0; i < inputSamples.length; i++) {
-              if (inputSamples[i].dts > firstPTS) {
+              if (inputSamples[i].dts > firstPTS && isPTSOrderRetained) {
                 break;
               }
+
+              const prevPTS = inputSamples[i].pts;
               inputSamples[i].dts -= delta;
               inputSamples[i].pts -= delta;
+
+              // check to see if this sample's PTS order has changed
+              // relative to the next one
+              if (i < inputSamples.length - 1) {
+                const nextSamplePTS = inputSamples[i + 1].pts;
+                const currentSamplePTS = inputSamples[i].pts;
+
+                const currentOrder = nextSamplePTS <= currentSamplePTS;
+                const prevOrder = nextSamplePTS <= prevPTS;
+
+                isPTSOrderRetained = currentOrder == prevOrder;
+              }
             }
           }
           logger.log(