Isn't this what YouTube calls content ID? They alert you that your content is up somewhere, then you have the option of monetizing it, or having it taken down.
Not quite trivial: people can crop, skew, vignette, mirror, timestretch and scale video to try to defeat it. YouTube's Content ID seems to be vulnerable to this sort of thing still.
I think that's why many of these systems focus on audio. It's harder to change in a way that beats fingerprinting but doesn't ruin the viewing experience.
https://support.google.com/youtube/answer/1311402