Closed / Open GOP

A closed group of pictures (frames) is often referred to as a closed GOP and the encoding solution must limit data compression to only the frames within the current GOP. This is sometimes erroneously referred to as a single I frame GOP, where each I frame starts the next group of pictures. However, multiple GOPs with a single I frame can be used in an open GOP method. A closed GOP merely means that the GOP decoded without requiring access to an adjacent GOP.