Noise shaping for predictive audio coding apparatus

An information coding apparatus comprising:

• a predictive signal generator that generates a predictive signal based on a past audio signal in an input audio signal and a predictive filter coefficient for predicting a present audio signal;
• a predictive residual signal generator that generates a difference between the present audio signal and the predictive signal as a predictive residual signal;
• a quantizer that quantizes a quantization input signal generated based on the predictive residual signal to generate a quantization output signal;
• a quantization error signal generator that generates a difference between the quantization input signal and the quantization output signal as a quantization error signal;
• a feedback signal generator that generates a feedback signal for controlling a frequency characteristic of a quantization noise after decoding based on the quantization error signal;
• a correction filter controller that calculates the quantization noise using the quantization error signal and a transfer function of the feedback signal generator and performs control so as to selectively add correction filters for frames of the present audio signal based on a calculation;
• and
• a quantization input signal generator that generates a difference between the predictive residual signal and the feedback signal as the quantization input signal,
• wherein the feedback signal generator is configured by a pole-zero filter that includes a filter coefficient of an all-pole filter which is based on spectral envelope information estimated by the input audio signal, a parameter for adjusting a peak level in the frequency characteristic of the quantization noise caused by the all-pole filter, and the predictive filter coefficient.