I'm looking for a video editor that will do what I want, which SHOULD be easy enough (the words that lead to months/years of work). In videos I will be editing, there will be a symbol/shape that will appear in the same position, with generally the same color at different times. Thinking of it as a watermark that comes in and out isn't too far off the mark. What I want is a program that will recognize that symbol, reliably, and apply a filter of my design whenever it appears.

Any advice on where to look would be appreciated. I've taken to looking at open-source software and re-learning how to program, so any faster ideas would save me a lot of trouble.