We have been processing and editing the CMT videos for the past couple of days and ran into a snag when it came to superimposing images on the laptop screen. The problem was that the actor moves the laptop on the x, y and z axis so it is quite a job to impose an image by hand. After some trial and error, I discovered a technique called “corner pinning”. Basically, the image you are imposing has 4 corners and each of those is linked to a tracker in the motion tracking controls. Wherever the tracker moves, corner pin moves with it. The actual image never moves, just each corner along with the relative perspective. Some segments where the laptop is at a sharp angle or moved too quick had to be done by hand. Regardless, this method probably saved us a few hours and would have worked even better if we put actual tracker points on the laptop screen rather than green screen fabric. Just another example of DDA problem solving!