From bfada6f7758ce6d0fc85445733b1abe291de045f Mon Sep 17 00:00:00 2001
From: Paul Adenot <paul@paul.cx>
Date: Thu, 5 Nov 2026 14:29:28 +0100
Subject: [PATCH] Check VideoFrame buffer size against coded size

The VideoFrame(data, init) constructor computed its required allocation size from the visible rect, so a buffer too small for the coded frame was accepted. Compute the layout over the coded rect instead, matching Chromium.

Fixes #516
---
 index.src.html | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/index.src.html b/index.src.html
index e4fadd2d..2d6cb6ae 100644
--- a/index.src.html
+++ b/index.src.html
@@ -3668,7 +3668,9 @@
 8. If |init|.{{VideoFrameBufferInit/layout}} [=map/exists=], assign its value
     to |optLayout|.
 9. Let |combinedLayout| be the result of running the [=VideoFrame/Compute
-    Layout and Allocation Size=] algorithm with |parsedRect|,
+    Layout and Allocation Size=] algorithm with «[ "x" → `0`, "y" → `0`,
+    "width" → |init|.{{VideoFrameBufferInit/codedWidth}},
+    "height" → |init|.{{VideoFrameBufferInit/codedHeight}} ]»,
     |init|.{{VideoFrameBufferInit/format}}, and |optLayout|.
 10. If |combinedLayout| is an exception, throw |combinedLayout|.
 11. If `data.byteLength` is less than |combinedLayout|’s