Patent ID: 8311816

Claim:
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 filter adjuster that performs control to selectively add correction filters for frames of the present audio signal based on a clipping frequency of the quantizer; 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.