Checks your stabilised footage for any black pixels in the corner. Use this in context to alert you to the problem when you didn't zoom your stabilisation up enough, thanks to John Fegan for this idea

To use, simply connect the input from your stabilised footage / node, play and view output. The 4 corner swatches show the corner pixel color, if rgb = 0,0,0 the swatch turns red. And the traffic light changes to red also. This is momentary but easier to see than a few black pixels.