Abbreviation for Group of Pictures. A GOP is a structured grouping of video frames used to make up an MPEG video stream. In a GOP, each frame is encoded according one of three possible schemes. These schemes involve complex algorithms that, among other things, can allow data from previous frames and/or subsequent frames to be utilized in their rendering. This interdependency of information makes it important for any codec decoding the stream to be able to work properly with frames that are grouped together in this manner so they can be decoded as a unit. One of these groupings is a GOP; the parameters of which are detailed in the MPEG specification.