Encoding device and decoding device

摘要

An encoding device ( 200 ) includes an MDCT unit ( 202 ) that transforms an input signal in a time domain into a frequency spectrum including a lower frequency spectrum, a BWE encoding unit ( 204 ) that generates extension data which specifies a higher frequency spectrum at a higher frequency than the lower frequency spectrum, and an encoded data stream generating unit ( 205 ) that encodes to output the lower frequency spectrum obtained by the MDCT unit ( 202 ) and the extension data obtained by the BWE encoding unit ( 204 ). The BWE encoding unit ( 204 ) generates as the extension data (i) a first parameter which specifies a lower subband which is to be copied as the higher frequency spectrum from among a plurality of the lower subbands which form the lower frequency spectrum obtained by the MDCT unit ( 202 ) and (ii) a second parameter which specifies a gain of the lower subband after being copied.