SOUND EFFECTER, FUNDAMENTAL TONE EXTRACTION METHOD, AND COMPUTER PROGRAM

The present invention provides a technique for shifting pitch to target pitch without detecting the original pitch directly, and for extracting the pitch of the audio waveform exactly. A phase compensator extracts 2 or more frequency channels each having frequency components of a harmonic overtone whose frequency is 1 or more times as higher than frequency of a fundamental tone of the original sound, from the frequency channels from which the frequency components are extracted by fast Fourier transform. The phase compensator calculates a scaling value to be used for converting the fundamental tone to another target fundamental tone, and performs phase compensation in accordance with the scaling value. A pitch shifter performs pitch scaling in accordance with the scaling value onto the audio data resultant from inverse fast Fourier transform onto the phase compensated frequency components. Thus, audio data representing the target fundamental tone are generated.