Introduction to video compression

This chapter introduces the Joint Photographic Experts Group (JPEG), Motion JPEG (M-JPEG), and Moving Picture Experts Group (MPEG) video compression techniques. Most data compression techniques, including run-length encoding (RLE) and LempeI-Ziv- Welch (LZW), accomplish compression by taking advantage of repeated substrings; performance is highly dependent upon the data being compressed. Data compression reduces the number of bits required to store or convey text, numeric, binary, image, sound, or other data, by exploiting statistical properties of the data. The reduction comes at the expense of some computational effort to compress and decompress. Data compression is, by definition, lossless: Decompression recovers exactly, bit for bit (or byte for byte), the data that was presented to the compressor. JPEG refers to a lossy compression method for still images. Its variant, NI-JPEG, is used for motion sequences; DVC equipment uses an AA-JPEG algorithm. NIPEG refers to a lossy compression standard for video sequences; AAPEG-2 is used in digital television distribution (for example, ATSC and DVB), and in DVD.