Signal processing apparatus and signal processing method, encoder and encoding method, decoder and decoding method, and program

摘要

The present invention relates to a signal processing apparatus and a signal processing method, an encoder and an encoding method, a decoder and a decoding method, and a program capable of reproducing music signal having a better sound quality by expansion of frequency band.;A sampling frequency conversion unit converts a sampling frequency of an input signal, and a sub-band division circuit divides the input signal after the sampling conversion into sub-band signals of sub-bands having the number corresponding to the sampling frequency.;A pseudo high band sub-band power calculation circuit calculates pseudo high band sub-band powers based on low band signals of the input signal and coefficient tables having coefficients for the respective high band sub-bands. A pseudo high band sub-band power difference calculation circuit compares high band sub-band powers and the pseudo high band sub-band powers to each other and selects a coefficient table from plural coefficient tables. In addition, a coefficient index which specifies the coefficient table is encoded and set as high band encoded data. The present invention can be applied to an encoder.

主权项

1. A signal processing apparatus comprising:
a sub-band division unit that receives an input signal having an arbitrary sampling frequency as an input and produces low band sub-band signals of a plurality of sub-bands on a low band side of the input signal and high band sub-band signals of a plurality of sub-bands on a high band side of the input signal, the sub-bands on the high band side having the number corresponding to the sampling frequency of the input signal; a pseudo high band sub-band power calculation unit that calculates pseudo high band sub-band powers, which are estimated values of powers of the high band sub-band signals, for the respective sub-bands on the high band side based on coefficient tables having coefficients for the respective sub-bands on the high band side and the low band sub-band signals, wherein each of the pseudo high band sub-band powers is calculated as a linear combination of a plurality of low band sub-band powers; a selection unit that compares high band sub-band powers of the high band sub-band signals and the pseudo high band sub-band powers to each other and selects one of a plurality of the coefficient tables; and a production unit that produces data containing coefficient information for obtaining the selected coefficient table.