Method and apparatus for processing digital audio signal

There is a sequence of samples having values representative of a waveform. Peak-corresponding samples are detected which correspond to respective peaks including local maximums and local minimums in the waveform. An ideal waveform peak is estimated from the value of each detected peak-corresponding sample and values of samples temporally adjacent to the detected peak-corresponding sample through interpolation. A time interval between every two temporally adjacent estimated peaks is calculated. One is selected from coefficients in accordance with the calculated time interval. The value of each detected peak-corresponding sample and values of samples temporally adjacent to the detected peak-corresponding sample are corrected in response to the selected coefficient, the value of an estimated peak corresponding to the detected peak-corresponding sample, and a time position of the estimated peak.