Nonuniform quantizers reduce perceived noise by spacing levels of rare louder signals farther apart

Evidence

One solution to this is to use nonuniform quantization, sometimes called nonlinear quantization, in which the levels are not equally spaced. By having the less-probable higher levels farther apart, the increased quantization error that results is more likely to be masked by the signal, and, because it’s less probable, the average signal-to-noise level does not increase. In fact, for a given number of levels, the average signal to noise reduces because the more likely levels are closer together and thus generate less quantization noise. MPEG-1 layer 3 uses a nonuniform quantizer to quantize the filtered signal samples. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2664

Categorization

• DEFINE: Defines nonuniform/nonlinear quantization as a concrete coding scheme drawing on psychoacoustic masking principles.