From b8f104d8b49dd649b5953fdb99c4077af645a3eb Mon Sep 17 00:00:00 2001
From: Vanilagy <1696106+Vanilagy@users.noreply.github.com>
Date: Mon, 12 Jan 2026 16:11:23 +0100
Subject: [PATCH] Fix disabled Matroska tracks crashing demuxer (closes #276)

---
 src/matroska/matroska-demuxer.ts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/matroska/matroska-demuxer.ts b/src/matroska/matroska-demuxer.ts
index 1c47d09..b373ff4 100644
--- a/src/matroska/matroska-demuxer.ts
+++ b/src/matroska/matroska-demuxer.ts
@@ -1012,6 +1012,11 @@ export class MatroskaDemuxer extends Demuxer {
 
 				this.readContiguousElements(slice.slice(dataStartPos, size));
 
+				// Check if track was disabled during parsing (e.g., by FlagEnabled being 0)
+				if (!this.currentTrack) {
+					break;
+				}
+
 				if (this.currentTrack.decodingInstructions.some((instruction) => {
 					return instruction.data?.type !== 'decompress'
 						|| instruction.scope !== ContentEncodingScope.Block