From ad26edc6b53019c3da7d40f9f04a2ff6c3f22acf Mon Sep 17 00:00:00 2001
From: Vanilagy <1696106+Vanilagy@users.noreply.github.com>
Date: Sun, 24 Aug 2025 14:49:33 +0200
Subject: [PATCH] Catch degenerate ISOBMFF matrices

---
 src/isobmff/isobmff-demuxer.ts | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/isobmff/isobmff-demuxer.ts b/src/isobmff/isobmff-demuxer.ts
index 20723ff..ba5ec2d 100644
--- a/src/isobmff/isobmff-demuxer.ts
+++ b/src/isobmff/isobmff-demuxer.ts
@@ -2755,7 +2755,14 @@ const extractRotationFromMatrix = (matrix: TransformationMatrix) => {
 	const sinTheta = m21 / scaleX;
 
 	// Invert the rotation because matrices are post-multiplied in ISOBMFF
-	return -Math.atan2(sinTheta, cosTheta) * (180 / Math.PI);
+	const result = -Math.atan2(sinTheta, cosTheta) * (180 / Math.PI);
+
+	if (!Number.isFinite(result)) {
+		// Can happen if the entire matrix is 0, for example
+		return 0;
+	}
+
+	return result;
 };
 
 const sampleTableIsEmpty = (sampleTable: SampleTable) => {