Encoding device and decoding device

An encoding device that encodes an input signal comprising:

• a time-frequency transforming unit operable to transform an input signal in a time domain into a frequency spectrum including a lower frequency spectrum;
• a band extending unit operable to generate extension data used for specifying a higher frequency spectrum at higher frequency than the lower frequency spectrum;
• and
• an encoding unit operable to encode the lower frequency spectrum and the extension data, and output the encoded lower frequency spectrum and extension data,
• wherein the band extending unit generates a first parameter and a second parameter as the extension data, the first parameter is used to determine a partial spectrum which is to be copied as the higher frequency spectrum from among a plurality of the partial spectrums which form the lower frequency spectrum, and the second parameter is used to determine a gain of the partial spectrum after being copied, and
• wherein the band extending unit generates a third parameter which is used to determine a frequency position of a partial spectrum including the lowest frequency component from partial spectrums used for generating the extension data among a plurality of the partial spectrums which form the lower frequency spectrum.

An encoding method for encoding an input signal, comprising:

• a time-frequency transforming step for transforming an input signal in a time domain into a frequency spectrum including a lower frequency spectrum;
• a band extending step for generating extension data used for specifying a higher frequency spectrum at higher frequency than the lower frequency spectrum;
• and
• an encoding step for encoding the lower frequency spectrum and the extension data, and outputting the encoded lower frequency spectrum and extension data,
• wherein the band extending step generates a first parameter and a second parameter as the extension data, the first parameter is used to determine a partial spectrum which is to be copied as the higher frequency spectrum from among a plurality of the partial spectrums which form the lower frequency spectrum, and the second parameter is used to determine a gain of the partial spectrum after being copied, and
• wherein the band extending step generates a third parameter which is used to determine a frequency position of a partial spectrum including the lowest frequency component from partial spectrums used for generating the extension data among a plurality of the partial spectrums which form the lower frequency spectrum.

A decoding device for decoding an encoded signal, comprising:

• a decoding unit operable to decode the encoded signal and to generate therefrom a lower frequency spectrum and extension data used for specifying a higher frequency spectrum at higher frequency than the lower frequency spectrum, the extension data including a first parameter, a second parameter and a third parameter, wherein the first parameter is used to determine a partial spectrum which is to be copied as the higher frequency spectrum from among a plurality of the partial spectrums which form the lower frequency spectrum, and the second parameter is used to determine a gain of the partial spectrum after being copied, and the third parameter which is used to determine a frequency position of a partial spectrum including the lowest frequency component from partial spectrums used for generating the extension data among a plurality of the partial spectrums which form the lower frequency spectrum,
• a higher frequency spectrum generating unit operable to generate the higher frequency spectrum based on the lower frequency spectrum and the extension data;
• and
• a time-frequency transforming unit operable to transform a frequency spectrum obtained by combining the generated higher frequency spectrum and the lower frequency spectrum into a signal in a time domain.

A decoding method of decoding an encoded signal, the decoding method comprising:

• a decoding step of decoding the encoded signal to generate therefrom a lower frequency spectrum and extension data used for specifying a higher frequency spectrum at higher frequency than the lower frequency spectrum, the extension data including a first parameter, a second parameter and a third parameter, wherein the first parameter is used to determine a partial spectrum which is to be copied as the higher frequency spectrum from among a plurality of the partial spectrums which form the lower frequency spectrum, and the second parameter is used to determine a gain of the partial spectrum after being copied, and the third parameter which is used to determine a frequency position of a partial spectrum including the lowest frequency component from partial spectrums used for generating the extension data among a plurality of the partial spectrums which form the lower frequency spectrum;
• a higher frequency spectrum generating step for generating the higher frequency spectrum based on the lower frequency spectrum and the extension data;
• and
• a time-frequency transforming step for transforming a frequency spectrum obtained by combining the generated higher frequency spectrum and the lower frequency spectrum into a signal in a time domain.