ARITHMETIC CODING IN LOSSLESS WAVE-FORM COMPRESSION

A method for applying arithmetic coding to lossless waveform compressi on is discussed, Arithmetic coding has been used widely in lossless te xt compression and is known to produce compression ratios that are nea rly optimal when the symbol table consists of an ordinary alphabet, In lossless compression of digitized waveform data, however, if each pos sible sample value is viewed as a ''symbol,'' the symbol table would b e typically very large and impractical, We therefore define a symbol t o be a certain range of possible waveform values, rather than a single value, and develop a coding scheme on this basis. The coding scheme c onsists of two compression stages, The first stage is lossless linear prediction, which removes coherent components from a digitized wavefor m and produces a residue sequence that is assumed to have a white spec trum and a Gaussian amplitude distribution, The prediction is lossless in the sense that the original digitized waveform can be recovered by processing the residue sequence, The second stage, which is the subje ct of this paper, is arithmetic coding used as just described, A formu la for selecting ranges of waveform values is provided, Experiments wi th seismic and speech waveforms that produce near-optimal results are included.