State of the art and trends in speech coding

An introductory review of some basic speech coding techniques covers the most important properties of speech production and hearing, the ubiquitous techniques of quantization and linear prediction, and a recital of the most important measures of coding performance. In the survey that follows, several standardized speech coding systems reflecting the state of the art in speech coding are discussed in terms of coding method, bit rate, performance, complexity and typical application areas. Major future trends are indicated on the basis of expected future standards. The paper, which primarily deals with narrowband speech coding systems, is concluded by a review of the state of affairs and an outline of the future trends in the area of wideband speech coding.