Patent ID: 8463602

Claim:
A coding apparatus comprising: an acquisition section that acquires a spectrum divided into at least a spectrum of a low frequency band and a spectrum of a high frequency band; a first coding section that codes the spectrum of the low frequency band; a second coding section that codes a shape of the spectrum of the high frequency band; a gain calculation section that divides the spectrum of the high frequency band into a plurality of subbands and calculates a gain of each of the subbands; a subband selection section that selects a subband having a maximum or minimum gain in the calculated gains of the subbands; a third coding section that codes only a gain of a specific subband of the spectrum of the high frequency band and a gain of the selected subband; a fourth coding section that codes information relating to a position of the selected subband; and an output terminal that outputs coded information obtained by the first, second, third, and fourth coding sections, wherein the third coding section comprises: a determination section that determines the gain of the specific subband of the spectrum of the high frequency band and the gain of the selected subband; an interpolation section that obtains a gain of a subband other than the specific subband in the spectrum of the high frequency band and the selected subband by interpolating the gains of the specific subband and the selected subband; and a change section that compares a spectrum indicated by the gains determined by the determination section and the gain determined by the interpolation section with the spectrum of the high frequency band, and changes the gains determined by the determination section according to a comparison result of these spectra, and codes the gains that were changed by the change section.