Video discrimination between different video formats.

摘要

A video discriminator for automatically providing a format select indicator generates from the number of vertical sync pulses (14) in a vertical interval of an input video signal and from the current state of the format select indicator (34) an error signal (22) if the number of vertical sync pulses is incompatible with the format select indicator. The error signal and a vertical sync detect pulse together with a horizontal line count determine (24) the format of the input video signal and cause the format select indicator to change to reflect the format of the input video signal.