Metronome

This is a visual metronome, sorta. The idea here is not to get a regular beat, but instead to eyeball visual smoothness. The orange ball should pass in smooth regular circles. If there's a background process or another application, like a webcam, that does something, like take a picture, once a second, this test will reveal that hiccup. Since there is so little going on in the movie, you then know that it's the system itself that is causing the hiccup as opposed to a coding issue.