Three-two pull down a term used in filmmaking and television production for the post-production process of transferring film to video. Film runs at a standard rate of 24 frames per second, whereas 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 to every second video frame, but the untrained eye can't see the addition of this extra video field.
The rate of NTSC video is approximately 29.97 frame per second, or one-tenths slower than 30 frame/s, due to the NTSC color encoding process that was corrected by slowing the video down. Although slight, the sync will catch up, and the audio can end up being several seconds out of sync with the image. In order to correct this error, the telecine can either pull up or pull down. A pull up will speed up the sound by .1%, used for transferring video to film. A pull down will slow the audio speed down by .1%, necessary for transferring film to video.
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