Decoding method and apparatus for an audio signal through high frequency compensation

A decoding apparatus that decodes a first encoded data that is encoded from a low-frequency component of an audio signal, and a second encoded data that is used when creating a high-frequency component of an audio signal from a low-frequency component and encoded in accordance with a certain bandwidth, into the audio signal, the decoding apparatus comprising:

• a high-frequency component detecting unit that divides the high-frequency component into bands with a certain interval range correspondingly to the certain bandwidth, and detects magnitude of power of the high-frequency components corresponding to each of the bands;
• a compensation-band determining unit that determines a band of a compensation subject which is a high-frequency component to be compensated based on an interval range of the high-frequency components divided by the high-frequency component detecting unit;
• a high-frequency component compensating unit that acquires a difference value by subtracting a power corresponding to the band of the compensation subject from a power corresponding to an adjacent band, acquires a change rate by dividing the difference value by a bandwidth of the band of the compensation subject, acquires an energy of a subdivided band by dividing the power corresponding to the band of the compensation subject by the bandwidth of the band of the compensation subject, acquires a compensating power by adding the energy of the subdivided band to a value which is computed by multiplying the change rate by a frequency change within the band of the compensation subject, and compensates the compensation subject in accordance with the compensating power;
• and
• a decoding unit that decodes the low-frequency component decoded from the first encoded data, and the high-frequency components compensated by the high-frequency component compensating unit, into the audio signal.