The restoration of the original frame sequence in video material. It is commonly used to reverse the telecine process that converted movies shot on film into interlaced video, back into the original 24 frames-per-second progressive film sequence. Cadence correction is part of deinterlacing, which, in order to apply the appropriate algorithm, must determine if the original movie was shot with a film or video camera. Also called "cadence detection," "film mode detection," "reverse telecine," "inverse telecine" and "reverse 3:2 pulldown."
Advanced correction circuits can detect almost any repeating cadence, such as 2:3:3:2, 3:2:3:2:2, 3:3, etc., which can be the result of splicing video and film clips together as well as careless editing in the studio. See deinterlace
Algolith's Dragonfly removed the telecine cadence in this example to restore the original progressive frame sequence at the bottom. The Dragonfly is a separate, high-end component used in home theaters (see videophile
). (Image courtesy of Algolith Inc., www.algolith.com)