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The μ-law CODEC

Douglas Lyon


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This paper describes how to use a CODEC (COder-DECoder) to encode, decode, synthesize and play AU-format audio data. The AU format use a μ-law (pronounced mu-law) compression technique improving dynamic range over the linear encoding of audio. The μ-law CODEC dates from 1965, yet is still in common use today.

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About the author


Douglas A. Lyon (M'89-SM'00) received the Ph.D., M.S. and B.S. degrees in computer and systems engineering from Rensselaer Polytechnic Institute (1991, 1985 and 1983). Dr. Lyon has worked at AT&T Bell Laboratories at Murray Hill, NJ and the Jet Propulsion Laboratory at the California Institute of Technology, Pasadena, CA. He is currently the Chairman of the Computer Engineering Department at Fairfield University, in Fairfield CT, a senior member of the IEEE and President of DocJava, Inc., a consulting firm in Connecticut. Dr. Lyon has authored or co-authored three books (Java, Digital Signal Processing, Image Processing in Java and Java for Programmers). He has authored over 30 journal publications. Email: Web:

Douglas A. Lyon “The μ-law CODEC”, in Journal of Object Technology , vol. 7. no. 8, November – December 2008 pp. 21-34

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