Patent ID: 7809557

Claim:
A vector quantization apparatus, comprising: a decoded vector storage that stores a decoded vector; a predictive coefficient storage that stores a predictive coefficient; a vector codebook that stores a plurality of code vectors; a parameter calculator that calculates a parameter for distortion calculation using input data comprising two elements, the decoded vector, and the predictive coefficient, wherein the parameter calculator calculates a sum component and a ratio component of the two elements, and then calculates a quantization target vector using the sum component and the ratio component of the two elements; a distortion calculator that calculates a coding distortion corresponding to each code vector stored in the vector codebook, using the parameter for distortion calculation and the predictive coefficient; and a comparator that, by comparing the coding distortions corresponding to the code vectors, finds and outputs an optimal code vector and a code corresponding to the optimal code vector, and updates the decoded vector storage using the optimal code vector.