Patent ID: 8306827

Claim:
A coding apparatus that encodes an input signal by information of n layers, where n is an integral number equal to or greater than 2, the apparatus comprising: a base layer coder that encodes the input signal and generates encoded information of a first layer; an i-th layer decoder that decodes encoded information of an i-th layer, where i is an integral number between 1 and n−1, and generates a decoded signal of the i-th layer; an adder that finds one of a first layer difference signal representing a difference between the input signal and a decoded signal of the first layer, and an i-th layer difference signal representing a difference between a difference signal of an (i−1)-th layer and a decoded signal of the i-th layer; a (i+1)-th layer enhancement layer coder that encodes the difference signal of the i-th layer and generates encoded information of a (i+1)-th layer; and an enhancement layer controller that controls a coding method in a second coder in a higher layer, which is higher than a predetermined layer according to a quantization result of coding parameters for a first coder in the predetermined layer, wherein one of the coders is a code-excited linear prediction (CELP) type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first linear prediction coefficient (LPC) codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second LPC codebook of a smaller size than the first LPC codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.