This was not the Rotograph. It was the Setback Camera, billed on screen as The Stereoptical Process. The Rotograph was a form of what was later called "Aerial Image Photography" where compositing of art elements like titles and animation could be made on a first generation negative to avoid using the Optical Printer and generational loss.
Amazing piece of animation history :) This was in the 1930s and they used some very sophisticated techniques. Where did you get this video, was it a DVD extra?
