VITC, which stands for Vertical Interval Time Code (abbreviated VITC and sometimes pronounced VIHT-see) is data which is encoded into the blank “vertical interval” between video frames.
Remembering that frames are pictures taken by a camera, after every picture that is successful there is a timing signal that is part of a video recording. It is recorded in the vertical blanking intervals between successive picture frames, hence the “vertical interval.”
The vertical blanking interval (VBI) is a portion of a television signal that can carry information other than video or audio, such as closed-caption text and stock market data. The interval in sending a video signal is required for the time it takes the electron gun in a television monitor’s cathode ray tube ( CRT ) to move back up to the top of the tube. VBI data can be inserted by a cable TV provider and transmitted to a special receiver that connects to a computer’s RS-232C port .
VITC assigns a specific time in hours, minutes, and seconds to each vertical blanking interval in a video recording, along with a frame number. The time code can be used to start a recording at a certain chronological time (such as 5:00:00 p.m.), or it can be used to keep a playback machine synchronized with a master time source. The former application might be used by a home television viewer, while the latter application would more likely be used by a broadcaster.
VITC is one of two timing schemes adopted by the Society of Motion Picture and Television Engineers ( SMPTE ) in the 1960s. The other, known as longitudinal time code ( LTC ), is used with audio recordings.