MediaStream canvas.captureStream() fails for Canvas Context2D
see the bug 230617 test case mediastream-canvas-to-video.html last few elements
Sorry, bug 230613.
*** Bug 231598 has been marked as a duplicate of this bug. ***
>This only occurs on Safari 15 and Safari Technology Preview. It does not occur on Safari 14.
> Here is a JSFiddle that reproduces the issue: https://jsfiddle.net/x8pz4u2y/1/. Click on the "Start" button to start capturing the canvas, which flashes between blue and green every second. Note that you may need to resize the window to get the video element to show in Safari 15 for some reason (which may be a separate bug but my main concern is that the resulting video is red).