A signal that was placed on line 19 of the vertical interval designed to provide a reference for luminance and chrominance levels. It isnt used much any more. Much of the television transmission world has replaced it with a reference signal for ghost canceling circuits.
VIR (VERTICAL INTERVAL REFERENCE)
Meaning of VIR (VERTICAL INTERVAL REFERENCE) in English
Film and video English vocabulary. Английский словарь фильмов и видео. 2012