Audio/Video Glossary

TABLE OF CONTENTS: (See TOC)
TALENT: A term used to refer to all on-camera human subjects in a video production, regardless if they have any or not.
TALLY LAMP: A signal lamp or LED installed on a video camera which informs performers and crew members when the camera is "live".
TB (Terabyte): 1,099,511,627,776 bytes of data or 1024 Gigabytes. This should not be confused with a Terabyte of disk space which is computed by multiplying 1000 x 1000 x 1000 x 1000.
TBC (Time Base Corrector): A device used to rectify any problems with a video signal’s sync pulses by generating a new clean time base, then synchronizing any other incoming video to this reference.
TDIF (Tascam Digital Interface): An 8-channel digital audio interface format via a 25-pin D-type connector.
TELECINE: Telecine is a term used to describe a device used to convert film to video. In advanced telecine machines, the movie film is digitally sampled and converted to video, frame by frame in real-time. Frame rate is the biggest problem encountered in film-to-video conversion. Movie film has a frame rate of 18, 24 or 30 fps (frames per second) contrasting with the 30 and 25 fps video frame rates of NTSC and PAL respectively. With NTSC, every fifth film frame is repeated when transferred to video. (See FLICKER)
TELE-PROMPTER: A device for displaying large, readable text on a partially transparent screen for video production. The tele-prompter uses a monitor mounted under the camera lens, facing up, and a mirrored glass which reflects the monitor’s image toward the talent. Since the camera shoots through the mirrored glass and the mirrored glass is transparent to the camera, the talent can look directly into the camera lens as they read the script from the glass.
TERMINATION SWITCH: A switch that connects and disconnects a load resistance to a video input, used to terminate the line. In order for a video signal to be correctly transmitted without loss, proper end of line impedance is essential. A 50 or 75 ohm resistor is usually employed to accomplish this. When the termination switch is off, the unterminated video signal is looped to the next device where the signal can be transmitted in parallel. The final device in the chain must be terminated using the termination switch. (See LOAD RESISTANCE)
TEST PATTERN: A chart with special patterns, placed in front of a television camera to generate a standard reference signal that can be used to adjust the camera and all equipment downstream.
THX: A set of quality-control standards pioneered by Lucasfilm, named for one of George Lucas’ early student films "THX-1138". Encompassing theatrical presentation, home playback, and video mastering, "THX Certification" means many different things. Home theater components, for example, are tuned in such a manner to compensate for differences between theatrical and home playback.
TIME CODE: A digital code number recorded onto a videotape for editing purposes. When decoded, the time code identifies every frame of a videotape using digits reading hours:minutes:seconds and frames. Each individual video frame is assigned a unique address, a must for accurate editing. The three time code standards used for audio and video are VITC, LTC and RC.
TITLING: The addition of text, symbols and graphic elements to a video image. Titles may be added to a video scene during shooting or in post-production. Sophisticated titling devices allow the user to prepare text and graphics in various sizes, fonts and colors to be triggered later, one-by-one, at appropriate places within a production. Many video cameras include basic titlers or permit externally-generated titles to be mixed with the video image during shooting.
TOC (Table of Contents): That part of a CD’s lead-in data which shows the number of tracks, their starting locations and the total length of the data area of the disc. The TOC does NOT show the length of each track, only its starting point.
TRACK-AT-ONCE: Mode of writing that allows a session to be written in a number of discrete write events called tracks. The mode mandates a minimum track length of 300 blocks (4 seconds), which equates to around 700KB, and a maximum of 99 tracks per disc. The disc may be removed from the writer and read in another writer before the session is closed (‘fixated’).
TRACKING: The angle and speed at which the tape passes the video heads. Due to small differences in head-to-tape alignment between VCRs, it is sometimes necessary to adjust the tracking control on a VCR when playing a tape recorded on another deck.
TRANSCODER: A device used to convert from one component format to another or one video standard to another. (e.g., PAL to SECAM)
TRANSFER RATE: The amount of data which is transferred from a CD-ROM to the computer. The CD-ROM transfer rate is limited by the speed at which the disc rotates in the drive. The conventional CD-ROM transfer rate is approximately 150 kilobytes/sec, referred to as 1x. Therefore, a quadruple speed (4x) CD-ROM drive can transfer data at a rate of 600 KB/sec.
TRUNCATION: The shortening of a digital word, wherein data belonging to the least-significant bits is lost.

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