SIGNAL PROCESSING APPARATUS AND SIGNAL PROCESSING METHOD, ENCODER AND ENCODING METHOD, DECODER AND DECODING METHOD, AND PROGRAM

• US 20130202118A1
• Filed: 04/11/2011
• Published: 08/08/2013
• Est. Priority Date: 04/13/2010
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yamamoto, Yuki, Chinen, Toru, Honma, Hiroyuki, Mitsufuji, Yuhki
• Granted Patent: US 9,583,112 B2
• Time in Patent Office: Days
• US Class Current: 381/22
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 21/0388 Details of processing therefor

Abstract

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.

Claims

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;

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.

2. The signal processing apparatus according to claim 1, wherein the sub-band division unit divides the input signal into the high band sub-band signals of a plurality of sub-bands such that the bandwidths of the sub-bands of the high band sub-band signals have the same width as those of sub-bands of the respective coefficients constituting the coefficient table.

3. The signal processing apparatus according to claim 1, further comprising:

an extension unit that, when the coefficient table does not have the coefficients of predetermined sub-bands, produces the coefficients of the predetermined sub-bands based on the coefficients for the respective sub-bands constituting the coefficient table.

4. The signal processing apparatus according to claim 1, wherein the data is high band encoded data which is obtained by encoding the coefficient information.

5. The signal processing apparatus according to claim 4, further comprising:

a low band encoding unit that encodes low band signals of the input signal to produce low band encoded data; and

a multiplexing unit that multiplexes the high band encoded data and the low band encoded data to produce an output code string.

6. A signal processing method of a signal processing apparatus which includes

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 table having coefficients for the respective sub-bands on the high band side and the low band sub-band signals,

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,

the method comprising the steps of causing:

the sub-band division unit to produce the low band sub-band signals and the high band sub-band signals;

the pseudo high band sub-band power calculation unit to calculate the pseudo high band sub-band powers;

the selection unit to select the coefficient table; and

the production unit to produce data containing the coefficient information.

7. A program causing a computer to execute processes including the steps of:

receiving an input signal having an arbitrary sampling frequency as an input and generating 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;

calculating 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;

comparing high band sub-band powers of the high band sub-band signals and the pseudo high band sub-band powers to each other and selecting one of a plurality of the coefficient tables; and

generating data containing coefficient information for obtaining the selected coefficient table.

8. A signal processing apparatus comprising:

a demultiplexing unit that demultiplexes input encoded data to at least low band encoded data and coefficient information;

a low band decoding unit that decodes the low band encoded data to produce low band signals;

a selection unit that selects a coefficient table which is obtained based on the coefficient information among a plurality of coefficient tables used for the production of high band signals and having coefficients for the respective sub-bands on a high band side;

an extension unit that produces the coefficients of predetermined sub-bands based on the coefficients of some sub-bands to extend the coefficient table;

a high band sub-band power calculation unit that determines the respective sub-bands constituting the high band signals based on information pertaining to sampling frequencies of the high band signals and calculates high band sub-band powers of high band sub-band signals of the respective sub-bands constituting the high band signals based on low band sub-band signals of the respective sub-bands constituting the low band signals and the extended coefficient table; and

a high band signal production unit that produces the high band signals based on the high band sub-band powers and the low band sub-band signals.

9. A signal processing method of a signal processing apparatus which includes

a demultiplexing unit that demultiplexes input encoded data to at least low band encoded data and coefficient information,

a low band decoding unit that decodes the low band encoded data to produce low band signals;

a selection unit that selects a coefficient table which is obtained based on the coefficient information among a plurality of coefficient tables used for the production of high band signals and having coefficients for the respective sub-bands on a high band side,

an extension unit that produces the coefficients of predetermined sub-bands based on the coefficients of some sub-bands to extend the coefficient table,

a high band sub-band power calculation unit that determines the respective sub-bands constituting the high band signals based on information pertaining to sampling frequencies of the high band signals and calculates high band sub-band powers of high band sub-band signals of the respective sub-bands constituting the high band signals based on low band sub-band signals of the respective sub-bands constituting the low band signals and the extended coefficient table, and

a high band signal production unit that produces the high band signals based on the high band sub-band powers and the low band sub-band signals,

the method comprising the steps of causing;

the demultiplexing unit to demultiplex the encoded data;

the low band decoding unit to produce the low band signals;

the selection unit to select the coefficient table;

the extension unit to extend the coefficient table;

the high band sub-band power calculation unit to calculate the high band sub-band powers; and

the high band signal production unit to produce the high band signals.

10. A program causing a computer to execute processes including the steps of:

demultiplexing input encoded data to at least low band encoded data and coefficient information;

decoding the low band encoded data to produce low band signals;

selecting a coefficient table which is obtained based on the coefficient information among a plurality of coefficient tables used for the production of high band signals and having coefficients for the respective sub-bands on a high band side;

generating the coefficients of predetermined sub-bands based on the coefficients of some sub-bands to extend the coefficient table;

determining the respective sub-bands constituting the high band signals based on information pertaining to sampling frequencies of the high band signals and calculating high band sub-band powers of high band sub-band signals of the respective sub-bands constituting the high band signals based on low band sub-band signals of the respective sub-bands constituting the low band signals and the extended coefficient table; and

generating the high band signals based on the high band sub-band powers and the low band sub-band signals.

11. An encoder 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;

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;

a high band encoding unit that encodes coefficient information for obtaining the selected coefficient table to produce high band encoded data;

a low band encoding unit that encodes low band signals of the input signal to produce low band encoded data; and

a multiplexing unit that multiplexes the low band encoded data and the high band encoded data to produce an output code string.

12. An encoding method of an encoder which includes

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,

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,

a high band encoding unit that encodes coefficient information for obtaining the selected coefficient table to produce high band encoded data,

a low band encoding unit that encodes low band signals of the input signal to produce low band encoded data, and

a multiplexing unit that multiplexes the low band encoded data and the high band encoded data to produce an output code string,

the method comprising the steps of causing:

the sub-band division unit to produce the low band sub-band signals and the high band sub-band signals;

the pseudo high band sub-band power calculation unit to calculate the pseudo high band sub-band powers;

the selection unit to select the coefficient table;

the high band encoding unit to produce the high band encoded data;

the low band encoding unit to produce the low band encoded data; and

the multiplexing unit to produce the output code string.

13. A decoder comprising:

a demultiplexing unit that demultiplexes input encoded data to at least low band encoded data and coefficient information;

a low band decoding unit that decodes the low band encoded data to produce low band signals;

a selection unit that selects a coefficient table which is obtained based on the coefficient information among a plurality of coefficient tables used for the production of high band signals and having coefficients for the respective sub-bands on a high band side;

an extension unit that produces the coefficients of predetermined sub-bands based on the coefficients of some sub-bands to extend the coefficient table;

a high band sub-band power calculation unit that determines the respective sub-bands constituting the high band signals based on information pertaining to sampling frequencies of the high band signals and calculates high band sub-band powers of high band sub-band signals of the respective sub-bands constituting the high band signals based on low band sub-band signals of the respective sub-bands constituting the low band signals and the extended coefficient table;

a high band signal production unit that produces the high band signals based on the high band sub-band powers and the low band sub-band signals; and

a synthesis unit that synthesizes the produced low band signals and the produced high band signals with each other to produce an output signal.

14. A decoding method of a decoder which includes

a demultiplexing unit that demultiplexes input encoded data to at least low band encoded data and coefficient information,

a low band decoding unit that decodes the low band encoded data to produce low band signals,

a selection unit that selects a coefficient table which is obtained based on the coefficient information among a plurality of coefficient tables used for the production of high band signals and having coefficients for the respective sub-bands on a high band side,

an extension unit that produces the coefficients of predetermined sub-bands based on the coefficients of some sub-bands to extend the coefficient table,

a high band sub-band power calculation unit that determines the respective sub-bands constituting the high band signals based on information pertaining to sampling frequencies of the high band signals and calculates high band sub-band powers of high band sub-band signals of the respective sub-bands constituting the high band signals based on low band sub-band signals of the respective sub-bands constituting the low band signals and the extended coefficient table,

a high band signal production unit that produces the high band signals based on the high band sub-band powers and the low band sub-band signals, and

a synthesis unit that synthesizes the produced low band signals and the produced high band signals with each other to produce an output signal,

the method comprising the steps of causing:

the demultiplexing unit to demultiplex the encoded data;

the low band decoding unit to produce the low band signals;

the selection unit to select the coefficient table;

the extension unit to extend the coefficient table;

the high band sub-band power calculation unit to calculates the high band sub-band powers;

the high band signal production unit to produce the high band signals; and

the synthesis unit to produce the output signal.