Footage recording on video tape - uses microprocessor to detect and process time data recorded on synchronising track

摘要

To facilitate accurate measurement of video tape footage a time marking facility has been incorporated in French television transmissions, allowing recording on the video tape channel normally used for picture synchronisation of timing data identifying each sequence in the transmission. A fixed binary code occurs at the commencement of each frame as the first part of the data, and is identified by a microprocessor, incorporated in the playback circuit of the video recorder, as representing the synchronising pulse, in response to which the microprocessor immediately supplies the synchronising pulse to the TV receiver. The second part of each data set indicates, in successive frames, hours, tens of minutes, minutes, tens of seconds, and seconds. The microprocessor uses this data to compute elapsed time and puts it on an electronic display.