A voice / audio coding apparatus comprising: a receiver that receives a voice / audio input signal in the time domain; a memory; and a processor that transforms the voice / audio input signal to a frequency domain; divide a frequency spectrum of the voice / audio signal to obtain a plurality of subbands; estimates an energy envelope that represents an energy level for each of the plurality of subbands; quantify the energy envelope; determines a plurality of groups from the quantized energy envelope, each consisting of the plurality of groups of a plurality of subbands; assigns, group by group, bits to the determined plurality of groups; assigns, subband by subband, the bits assigned to each of the plurality of groups to the plurality of subbands included in each of the groups; and encodes the frequency spectrum using the bits assigned to the subbands, in which when determining the plurality of groups, the processor identifies one or more dominant groups that are comprised of a dominant frequency subband in which an envelope of spectrum energy of frequency has a local maximum value and mutually adjacent subbands on both sides of the dominant frequency subband, each of the adjacent subbands forming mutually a downward slope of an energy envelope, and identifies one or more non-dominant groups that are composed of adjacent subbands mutually distinct from those included in the one or more dominant groups.
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