Ok here is something weird - when I load all 18 videos at the start and use a variable to signify which one to update() and draw() - I get very strange speed results whereby every speed from 1 - 1.9 looks fine, 2 drops to be a lot slower, then 2.1 goes fast again.
It seems to be that just by creating more instances of ofxWMFVideoPlayer (and only loading 3 of them with videos) is enough to cause this.
Any ideas why that would happen?