Index: openacs-4/packages/proctoring-support/www/resources/proctoring.js
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/proctoring-support/www/resources/Attic/proctoring.js,v
diff -u -r1.1.2.17 -r1.1.2.18
--- openacs-4/packages/proctoring-support/www/resources/proctoring.js	15 Dec 2022 13:41:22 -0000	1.1.2.17
+++ openacs-4/packages/proctoring-support/www/resources/proctoring.js	20 Dec 2022 15:20:54 -0000	1.1.2.18
@@ -697,7 +697,8 @@
             const canvas = document.createElement('canvas');
             canvas.width = iWidth;
             canvas.height = iHeight;
-            canvas.getContext('2d').drawImage(video, 0, 0, iWidth, iHeight);
+            const ctx = canvas.getContext('2d', {willReadFrequently: true});
+            ctx.drawImage(video, 0, 0, iWidth, iHeight);
 
             // In the future we might be stricter about black pictures...
             // if (this.isCanvasMonochrome(canvas)) {