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.