gag reel. Comic reel made of a show’s outtakes and crew tomfoolery shown at the end-of the-season or wrap party. Sound effects, music, and narration are often added.
gain control. Audio pot that raises or lowers the record, mix, or playback signal strength.
gain. The increase or decrease in strength of an electrical signal measured in decibels or number-of-times of magnification. Mixers constantly “ride the gain” to ensure a consistent audio level from show start to finish.
garbage matte. A rough matte created when keying green screens to remove garbage (undesirable elements such as wires or models) or retain parts of images e.g. light spills that the green screen might wipe out.
GB. See gigabyte.
generation loss. Loss of picture and sound quality which occurs each time an analog tape is dubbed to another tape.
genlock. Locking one device to another via an internal signal generator to achieve synchronization.
gigabyte. GB. Approximately 1024 megabytes or 1 billion bytes. A unit of measurement used to measure computer files sizes, data storage, and memory.
glitch. Distortion of video or audio on an analog tape during playback.
GOP. Group of pictures (frames). In video coding, how intra- and inter-frames are ordered and arranged.
GPI. General Purpose Interface. An interface that allows the computer to control specific functions on a variety of remote devices. Used extensively on switchers and online machines. Usually means a serial connection (RS232 or RS422) between computers.
grade. Color time a film or tape. See also color correct and timing.
gray scale. The 7-10 shades of gray which form a test pattern that corresponds to the brightness range that a television system can reproduce. Used by cinematographers, film, and video technicians.
greenlight. To formally approve a project and acquire it’s financing. Once it’s greenlit (greenlighted), a project moves into the development phase.
green screen. Special effect created by shooting a subject in front of a green (or blue) screen. Shot 1, a live action shot, is the background. Shot 2, the green screen shot, contains the subject (talent) and is the foreground. When the two shots are composited (merged), the green screen washes out and the subject appears to react to what’s happening in the background, e.g. a farmers reacting to a giant spider. See also chroma-key.
guide track. See work track.
GVG. Grass Valley Group. Northern California company renowned for its switchers, online editing systems, and Profile video file system.
GVX. Graphics file.