VOICE AUDIO ENCODING DEVICE, VOICE AUDIO DECODING DEVICE, VOICE AUDIO ENCODING METHOD, AND VOICE AUDIO DECODING METHOD

Provided are a voice audio encoding device, voice audio decoding device, voice audio encoding method, and voice audio decoding method that efficiently perform bit distribution and improve sound quality. Dominant frequency band identification unit (301) identifies a dominant frequency band having a norm factor value that is the maximum value within the spectrum of an input voice audio signal. Dominant group determination units (302-1 to 302-N) and non-dominant group determination unit (303) group all sub-bands into a dominant group that contains the dominant frequency band and a non-dominant group that contains no dominant frequency band. Group bit distribution unit (308) distributes bits to each group on the basis of the energy and norm variance of each group. Sub-band bit distribution unit (309) redistributes the bits that have been distributed to each group to each sub-band in accordance with the ratio of the norm to the energy of the groups.