From 052feab9f3a3998e95525e5aab92234d82accd6a Mon Sep 17 00:00:00 2001
From: Rob Walch <rob@jwplayer.com>
Date: Mon, 13 Jul 2020 12:14:14 -0400
Subject: [PATCH] Clamp DTS after timecode hole/overlap check and Safari frame
 duration calculation

---
 src/remux/mp4-remuxer.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/remux/mp4-remuxer.js b/src/remux/mp4-remuxer.js
index 645f1c8ee8c..875473e29be 100644
--- a/src/remux/mp4-remuxer.js
+++ b/src/remux/mp4-remuxer.js
@@ -285,6 +285,10 @@ class MP4Remuxer {
       mp4SampleDuration = Math.round((lastDTS - firstDTS) / (inputSamples.length - 1));
     }
 
+    // Clamp first DTS to 0 so that we're still aligning on initPTS,
+    // and not passing negative values to MP4.traf. This will change initial frame compositionTimeOffset!
+    firstDTS = Math.max(firstDTS, 0);
+
     let nbNalu = 0, naluLen = 0;
     for (let i = 0; i < nbSamples; i++) {
       // compute total/avc sample length and nb of NAL units