Computer Dictionary of Information Technology

non-uniform quantising logarithmic compression

The kind of compression often applied to a sound waveform. Logarithmic compression is a good match for the human ear's sensitivity but cannot handle zero amplitude (for which the logarithm is negative infinity). There are two standard compression functions which give a smooth transition between the logarithmic function and a linear segment passing through the origin: mu-law (North America) and A-law (ITU-T).