JPEG and motion-JPEG (M-JPEG) compression

This chapter describes Joint Photographic Experts Group (JPEG), which is a standard for lossy compression of still images based upon the discrete cosine transform (DCT). JPEG is rarely used directly in video, but it forms the basis of Motion-JPEG (M-JPEG) used in desktop video editing and digital video (DV) compression. Also, JPEG techniques form the core of MPEG refers to the use of a JPEG-like algorithm to compress each field or frame in a sequence of video fields or frames. M-JPEG systems use the methods of JPEG, if conform to the ISO/IEC JPEG standard. DV is a specific type of M-JPEG that is well standardized. The JPEG standard, cited in the margin, defines four modes: sequential, hierarchical, progressive, and lossless. The JPEG standard accommodates discrete cosine transform (DCT) coefficients having from 2 to 16 bits, and accommodates two different entropy coders (Huffman and arithmetic). The ISO/IEC standard for JPEG defines a bitstream, consistent with the original expectation that JPEG would be used across communication links.