I've looked at a few apps that allow you to layer effects over videos and found them impressive. Today I'm looking at Green Screen Movie FX Studio (US$4.99, universal) for iPhone, iPod touch and iPad. It goes a step beyond some others and lets you create impressive green screen effects. The app also allows tweening so you can set a few positions for an effect, like a tank, a rocket or dinosaur, and fills in the animation between the starting and ending points.
The app features 88 video FX layers, which you can resize, rotat
