ABSTRACT
This chapter examines the Discrete Cosine Transform (DCT) and the processing that follows it. The DCT is a transform with the characteristic that it takes values in a matrix and concentrates most of the information about them into just a few coefficients. The DCT has several properties that make it a particularly apt choice for use in compressing digital video. Most of these relate to ways in which the values of the coefficients can be mathematically manipulated to reduce the amount of data to be transmitted. Most of this manipulation takes the form of number crunching. A technique that can be applied to the DCT is the zig-zag scanning of the coefficients. The value of variable length coding can be seen through use of an example. The mechanism for sending the residue is a major part of each digital compression system.
