KEY FRAME

(n.) A video frame used in decoding a combined interframe compression and intraframe compression . A decoder cannot decompress most of the video frames without referring to preceding--and sometimes succeeding--frames. However, the first frame in a movie, and usually other frames, does not have interframe dependencies and can be decoded in isolation. These key frames not only start the movie, but enable the decoder to decompress other frames without playing the movie from the beginning. See also data compression