Frequency band extending device and method, encoding device and method, decoding device and method, and program

A decoding method comprising:

• a demultiplexing step arranged to demultiplex input encoded data into at least low frequency encoded data and an index;
• a low frequency decoding step arranged to decode said ow frequency encoded data to generate a low frequency signal;
• a sub-band dividing step arranged to divide the band of said low frequency signal into a plurality of low frequency sub-bands to generate a low frequency sub-band signal for each of said low frequency sub-bands;
• and
• a generating step arranged to generate a high frequency signal based on said index and said low frequency sub-band signal.

A non-transitory computer-readable medium causing a computer to execute processing comprising:

• a demultiplexing step arranged to demultiplex input encoded data into at least low frequency encoded data and an index;
• a low frequency decoding step arranged to decode said low frequency encoded data to generate a low frequency signal;
• a sub-band dividing step arranged to divide the band of said low frequency signal into a plurality of low frequency sub-bands to generate a low frequency sub-band signal for each of said low frequency sub-bands;
• and
• a generating step arranged to generate a high frequency signal based on said index and said low frequency sub-band signal.

A decoding device comprising:

• demultiplexing means configured to demultiplex input encoded data into low frequency encoded data and an index for obtaining an estimating coefficient used for generation of a high frequency signal;
• low frequency decoding means configured to decode said low frequency encoded data to generate a low frequency signal;
• sub-band dividing means configured to divide the band of said low frequency signal into a plurality of low frequency sub-bands to generate a low frequency sub-band signal for each of said low frequency sub-bands;
• feature amount calculating means configured to calculate feature amount that expresses a feature of said encoded data using at least one of said low frequency sub-band signal and said low frequency signal;
• high frequency sub-band power calculating means configured to calculate a high frequency sub-band power of the high frequency sub-band signal of said high frequency sub-band by multiplexing said feature amount by said estimating coefficient determined by said index of a plurality of said estimating coefficients prepared beforehand regarding each of a plurality of high frequency sub-bands making up the band of said high frequency signal, and obtaining the sum of said feature amount by which said estimating coefficient has been multiplied;
• and
• high frequency signal generating means configured to generate said high frequency signal using said high frequency sub-band power and said low frequency sub-band signal.

A decoding method comprising:

• a demultiplexing step arranged to demultiplex input encoded data into low frequency encoded data and an index for obtaining an estimating coefficient used for generation of a high frequency signal;
• a low frequency decoding step arranged to decode said low frequency encoded data to generate a low frequency signal;
• a sub-band dividing step arranged to divide the band of said low frequency signal into a plurality of low frequency sub-bands to generate a low frequency sub-band signal for each of said low frequency sub-bands;
• a feature amount calculating step arranged to calculate feature amount that expresses a feature of said encoded data using at least one of said low frequency sub-band signal and said low frequency signal;
• a high frequency sub-band power calculating step arranged to calculate a high frequency sub-band power of the high frequency sub-band signal of said high frequency sub-band by multiplexing said feature amount by said estimating coefficient determined by said index of a plurality of said estimating coefficients prepared beforehand regarding each of a plurality of high frequency sub-bands making up the band of said high frequency signal, and obtaining the sum of said feature amount by which said estimating coefficient has been multiplied;
• and
• a high frequency signal generating step arranged to generate said high frequency signal using said high frequency sub-band power and said low frequency sub-band signal.

A non-transitory computer-readable medium causing a computer to execute processing comprising:

• a demultiplexing step arranged to demultiplex input encoded data into low frequency encoded data and an index for obtaining an estimating coefficient used for generation of a high frequency signal;
• a low frequency decoding step arranged to decode said low frequency encoded data to generate a low frequency signal;
• a sub-band dividing step arranged to divide the band of said low frequency signal into a plurality of low frequency sub-bands to generate a low frequency sub-band signal for each of said low frequency sub-bands;
• a feature amount calculating step arranged to calculate feature amount that expresses a feature of said encoded data using at least one of said low frequency sub-band signal and said low frequency signal;
• a high frequency sub-band power calculating step arranged to calculate a high frequency sub-band power of the high frequency sub-band signal of said high frequency sub-band by multiplexing said feature amount by said estimating coefficient determined by said index of a plurality of said estimating coefficients prepared beforehand regarding each of a plurality of high frequency sub-bands making up the band of said high frequency signal, and obtaining the sum of said feature amount by which said estimating coefficient has been multiplied;
• and
• a high frequency signal generating step arranged to generate said high frequency signal using said high frequency sub-band power and said low frequency sub-band signal.