Algorithms for manipulating compressed images

A family of algorithms that implement operations on compressed digital images is described. These algorithms allow many traditional image manipulation operations to be performed 50 to 100 times faster than their brute-force counterparts. It is shown how the algebraic operations of pixel-wise and scalar addition and multiplication, which are the basis for many image transformations, can be implemented on compressed images. These operations are used to implement two common video transformations: dissolving one video sequence into another and subtitling. The performance of these operations is compared with the brute-force approach. The limitations of the technique, extensions to other compression standards and the relationship of this research to other work in the area are discussed.<>