Best Way to trigger movie from tracked color?

I'm trying to figure out what the "best" way to trigger a movie file to play when a centroid object (e.g.., like in the color tracking example), is on a certain spot x/y.

It seems as though, if two images are being composited with a blend shader, that when a movie "runs" out, that the image output freezes. There also doesn't seem to be an explicit "play" method in gpuimagemovie.

Given this, should/could I achieve what I want to do by always playing a "blank" movie, and use the result of the centroid to switch the movie path to the desired movie when the color is tracked? Or is there some kind of other call I can make to ignore whether the movie has finished, so that output doesn't ever freeze... then I can just worry about the movie play starting(?).