Audio signal processing apparatus and audio signal processing method

An audio signal processing method comprising:

• generating, by using a processor, a first frame signal by multiplying a divided input audio signal by a prescribed first window function, the divided input audio signal being included in a divided signal string generated by dividing an audio input signal into frames of a prescribed frame length;
• transforming, by using the processor, the first frame signal into a frequency spectrum;
• adjusting, by using the processor, an amplitude component of the frequency spectrum;
• applying, by using the processor, inverse transform to the amplitude component after adjustment and to a phase component of the frequency spectrum to generate a second frame signal in a time domain;
• identifying, by using the processor, a segment in an overlapping section between the second frame signal and an immediately preceding frame signal of the second frame signal such that an absolute value of an amplitude of the second frame signal at a start end of the segment becomes smaller than an absolute value of an amplitude of the second frame signal at a terminal end of the overlapping section, the immediately preceding frame signal being generated from a immediately preceding divided input audio signal of the divided input audio signal in the divided signal string;
• and
• in the identified segment, adding, by using the processor, the immediately preceding frame signal and the second frame signal.

A non-transitory computer readable recording medium having stored therein a program for causing a computer to execute an audio signal processing, the processing comprising:

• generating, by the computer, a first frame signal by multiplying an input signal divided into frames of a prescribed frame length by a prescribed first window function;
• transforming, by the computer, the first frame signal into a frequency spectrum;
• adjusting, by the computer, an amplitude component of the frequency spectrum;
• applying, by the computer, inverse transform to the amplitude component after adjustment and to a phase component of the frequency spectrum to generate a second frame signal in a time domain;
• identifying, by the computer, a segment in an overlapping section between the second frame signal and an immediately preceding frame signal of the second frame signal such that an absolute value of an amplitude of the second frame signal at a start end of the segment becomes smaller than an absolute value of an amplitude of the second frame signal at a terminal end of the overlapping section, the immediately preceding frame signal being generated from a immediately preceding divided input audio signal of the divided input audio signal in the divided signal string;
• and
• in the identified segment, adding, by the computer, the immediately preceding frame signal and the second frame signal.