Abstract: An in-station method and apparatus for encoding television programs, including commercials, with a digital identification code recorded on a selected video scan line which is not normally visible to the television viewer, and for verifying the proper airing of such programs by such television broadcast station. The encoding and decoding is performed at the broadcast station during its normal operating procedure. The program is encoded during the normal dubbing procedure when a program video tape is dubbed to a video cartridge for use by the broadcast station's library management system. The decoder is located either at the station at an off-air monitor, or at the transmitter, where it monitors the transmitted signal from the broadcast station and records the occurrence of encoded programs or commercials. The information generated is stored locally for later transmission to a host computer where the information can be combined with information from other broadcast stations and other databases.