Three-two pull-down (3:2 pull down) is a term used in filmmaking and television production for the post-production process of transferring film to video.
It converts 24 frames per second into 29.97 frames per second. Roughly speaking, converting every 4 frames into 5 frames plus a slight slow down in speed. The film runs at a standard rate of 24 frames per second, whereas the NTSC video has a signal frame rate of 29.97 frames per second. Every interlaced video frame has two fields for each frame. The three-two pull-down is where the telecine adds a third video field (a half-frame) to every second video frame, but the untrained eye cannot see the addition of this extra video field. In the figure, the film frames A-D are true or original images since they have been photographed as a complete frame. The A, B, and D frames on the right in the NTSC footage are original frames. The third and fourth frames have been created by blending movie fields from different frames.