Film runs at 24 frames per second and video at 30 frames or 60 half frames (fields) per second. In order to make 24 frames play at the same time rate (speed) as 60 half frames (fields) you do the following. Film frame 1 goes into video fields 1A and 1B, film frame 2 goes into video fields 2A,2B, and 3A (repeat). Then film frame 3 goes into video fields 3B and 4A, film frame 4 into video fields 4B,5A and 5B (repeat). Which means even film frame frames into 2 video fields (1 video frame), odd film frames into 3 video fields (1.5 video frames. Hence the 2/3 pull down.
This is why an improperly flagged DVD containing film source shown on a progressive display will show vertical lines when a scene changes. You are actually seeing 1 field (half a frame) of the last scene that was not "weaved" together with its proper frame.
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!