Digital audio signal coding and/or deciding method

摘要

A method and apparatus for high efficiency encoding audio signals. The high-efficiency encoding apparatus includes a transform circuit for transforming an input signal into frequency components and a signal component separating circuit for separating the frequency components into tonal components and noisy components. The high-efficiency encoding apparatus also includes a tonal component encoding circuit for encoding tonal components and a noisy component encoding circuit for encoding noisy components. The tonal components are made up only of signal components of a specified band and encoded along with the information specifying the band. The noisy components are normalized and quantized every pre-set encoding unit and encoded along with the quantization precision information. The information on the numbers of quantization steps of the noisy components is encoded with a smaller number of bits for the high-range side than for the low-range side. With the high-efficiency encoding method and apparatus, not only the main information but also the subsidiary information may be improved in encoding efficiency, while the degree of freedom may be assured in the method of representing the subsidiary information and satisfactory encoding may be achieved.