DIGITAL SIGNAL PROCESSING METHOD, LEARNING METHOD, APPARATUSES FOR THEM, AND PROGRAM STORAGE MEDIUM

Power spectrum data is calculated from a digital audio signal D10. A part of power spectrum data is extracted from thus calculated power spectrum data. Classification is made based on the extracted part of power spectrum data. And the digital audio signal D10 is converted by a predicting method that corresponds to the classified class. Thereby, conversion further adapted to the characteristic of the digital audio signal D10 can be performed.