Video processing system with real time program duration compression and expansion

This invention relates to video signal processing methods and systems. More particularly, this invention relates to methods and systems for altering the content of video program material to expand or contract the total length of an entire program or program segment. The running real time length of combined video and audio signal programs is shortened or lengthened by deleting or repeating individual fields or frames and corresponding amounts of audio segments. The video and audio portions of the programming material are separated and subjected to processing through a pair of program time changing units. The video portion is processed by deleting individual fields or frames on a manual, periodic or automatic basis. Manual deletion is done by an operator observing the program material on a monitor. Periodic deletion is performed automatically after the operator specifies the total amount of time (or number of fields or frames) to be deleted, with every ith frame or field deleted regardless of content. Automatic deletion is done in a fashion similar to periodic deletion, but the fields or frames are examined and are deleted on the basis of the amount of between frame motion. Audio segment deletion is done either manually, periodically or automatically, and the audio segments removed need not match the deleted frame video, but may be taken from different frames, so long as the total time length of the deleted audio segments equals the total time of the deleted video frames, and also provided that the differential delay between the processed video and processed audio does not exceed the lip sync criterion. A pause function disables the deletion or insertion process for program materials which may not be altered in any way.