| 摘要 |
PROBLEM TO BE SOLVED: To conduct nonlinear inverse quantization processing with high accuracy and a small arithmetic amount in the case of decoding data that are converted into frequency region data, quantized, encoded and compressed. SOLUTION: The signal decoding method of this invention includes a step s1 of dividing decoded input data X into higher-order bits X- high and lower- order bits X- low, a step s2 of checking whether the higher-order bits are 0, a step s3 of referencing an inverse quantization table Q by using the lower-order bits for a Key when the higher-order bits are 0 to obtain a result of the inverse quantization arithmetic operation, a step s4 of referencing a representative table V to obtain a representative value V by using the higher-order bits for the Key when the higher-order bits are not 0 and referencing an interpolation table G by using the higher-order bits for the Key to obtain the gradient g at that time, and a step s5 of using the representative value V, the gradient g and the divided lower-order bits to calculate V+g*X- low to obtain the result of the nonlinear inverse quantization arithmetic operation with respect to the input data X at that time. |
