Most video formats consist of compressed and encoded images like the frames in a movie.
In order to minimize the amount of space, ingenious methods have been developed. Most revolve around the idea of key frames which indicate places where significant motion has taken place and otherwise occur at regular intervals. Other frames are encoded relative to these key frames so that they consist of a small amount of pertinent information. These new formats allow videos to be played as they are downloaded and over modest bandwidths. Thi s guidebook uses streaming technology in its video presentations.