Patent ID: 7392176

Claim:
An encoding device that encodes audio data comprising: a splitting unit operable to split an audio data string into a fixed number of contiguous audio data; a transforming unit operable to transform the split audio data into spectral data in a frequency domain; a dividing unit operable to divide the spectral data obtained by the transforming unit into a plurality of groups of spectral data, and to divide the spectral data which are divided into groups into spectral data in a lower frequency band of f 1 Hz and less and spectral data in a higher frequency band over f 1 Hz; a lower frequency band encoding unit operable to quantize and encode each group of the divided spectral data in the lower frequency band; a sub information generating unit operable to generate, for each group of spectral data in the higher frequency band, information specifying a spectrum of spectral data in the lower frequency band which is most approximate to the spectrum in each group of spectral data in the higher frequency band as sub information indicating a characteristic of a spectrum in each group of spectral data in the higher frequency band; a higher frequency band encoding unit operable to encode the generated sub information; and an outputting unit operable to integrate the encoded data obtained by the lower frequency band encoding unit and the encoded sub information obtained by the higher frequency band encoding unit, and output the integrated result, wherein f 1 is a half or less of a sampling frequency f 2 for the audio data string.