ENCODING DEVICE AND METHOD, DECODING DEVICE AND METHOD, AND PROGRAM

• US 20140200900A1
• Filed: 08/14/2012
• Published: 07/17/2014
• Est. Priority Date: 08/24/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yamamoto, Yuki, Chinen, Toru
• Granted Patent: US 9,361,900 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/265 Pre-filtering, e.g. high frequency emphasis prior to encoding
• CPC Class Codes: G10L 21/038 using band spreading techniques

Abstract

The present technology relates to an encoding device and method, a decoding device and method, and a program, which enable improvement of audio quality.

A QMF sub-band power calculation unit calculates power of a QMF sub-band signal of a high frequency QMF sub-band among a plurality of the QMF sub-bands constituting an input signal. A high frequency sub-band power calculation unit carries out an operation to weight more a QMF sub-band power having larger power as for a sub-band including a number of the high frequency QMF sub-bands to calculate high frequency sub-band power of the sub-band. The multiplexing circuit multiplexes high frequency encoded data and low frequency encoded data for outputting. The high frequency encoded data is selected based on the high frequency sub-band power and obtained by encoding information used for obtaining a high frequency component of the input signal by estimating, and the low frequency encoded data is obtained by encoding low frequency components of the input signal. The present technology can be applied to encoding devices.

Claims

1. An encoding device comprising:

a sub-band dividing unit configured to divide a frequency band of an input signal and generate a first sub-band signal of a first sub-band on a high frequency side of the input signal;

a first sub-band power calculation unit configured to calculate first sub-band power of the first sub-band signal based on the first sub-band signal;

a second sub-band power calculation unit configured to carry out an operation to weight more the first sub-band power having larger power, and calculate second sub-band power of a second sub-band signal including a number of the continuous first sub-bands;

a generating unit configured to generate data to obtain, by estimating, a high frequency signal of the input signal based on the second sub-band power;

a low frequency encoding unit configured encode a low frequency signal of the input signal to generate low frequency encoded data; and

a multiplexing unit configured to multiplex the data and the low frequency encoded data to generate an output code string.

2. The encoding device according to claim 1, further comprising

a pseudo high frequency sub-band power calculation unit configured to calculate pseudo high frequency sub-band power which is an estimated value of the second sub-band power based on the input signal or a feature amount obtained from the low frequency signal,

wherein the generating unit generates the data by comparing the second sub-band power with the pseudo high frequency sub-band power.

3. The encoding device according to claim 2, wherein

the pseudo high frequency sub-band power calculation unit calculates the pseudo high frequency sub-band power based on the feature amount and an estimating coefficient preliminarily prepared, and

the generating unit generates the data to obtain any one of a plurality of the estimating coefficients.

4. The encoding device according to claim 3, further comprising

a high frequency encoding unit configured to generate high frequency encoded data by encoding the data,

wherein the multiplexing unit multiplexes the high frequency encoded data and the low frequency encoded data to generate the output code string.

5. The encoding device according to claim 4, wherein the second sub-band power calculation unit calculates the second sub-band power by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m.

6. The encoding device according to claim 4,

wherein the second sub-band power calculation unit calculates the second sub-band power by obtaining a weighted mean value of the first sub-band power, using the weight which becomes larger as the first sub-band power becomes larger.

7. An encoding method comprising steps of:

dividing a frequency band of an input signal and generating a first sub-band signal of a first sub-band on a high frequency side of the input signal;

calculating first sub-band power of the first sub-band signal based on the first sub-band signal;

carrying out an operation to weight more the first sub-band power having larger power, and calculating second sub-band power of a second sub-band signal including a number of the continuous first sub-bands;

generating data to obtain, by estimating, a high frequency signal of the input signal based on the second sub-band power;

encoding a low frequency signal of the input signal to generate low frequency encoded data; and

multiplexing the data and the low frequency encoded data to generate an output code string.

8. A program causing a computer to execute processes comprising steps of:

dividing a frequency band of an input signal and generating a first sub-band signal of a first sub-band on a high frequency side of the input signal;

calculating first sub-band power of the first sub-band signal based on the first sub-band signal;

carrying out an operation to weight more the first sub-band power having larger power, and calculating second sub-band power of a second sub-band signal including a number of the continuous first sub-bands;

generating data to obtain, by estimating, a high frequency signal of the input signal based on the second sub-band power;

encoding a low frequency signal of the input signal to generate low frequency encoded data; and

multiplexing the data and the low frequency encoded data to generate an output code string.

9. A decoding device comprising:

a demultiplexing unit configured to demultiplex an input code string into data and low frequency encoded data, wherein the data is generated based on second sub-band power of a second sub-band signal including a number of the continuous first sub-bands on a high frequency side of an input signal, the second sub-band power is calculated by weighting more first sub-band power having larger power among first sub-band power of the first sub-bands and used for obtaining, by estimating, a high frequency signal of the input signal, and the low frequency encoded data is obtained by encoding the low frequency signal of the input signal;

a low frequency decoding unit configured to decode the low frequency encoded data to generate a low frequency signal;

a high frequency signal generating unit configured to generate a high frequency signal based on an estimating coefficient obtained from the data and the low frequency signal obtained from the decoding; and

a synthesizing unit configured to generate an output signal based on the generated high frequency signal and the low frequency signal obtained from the decoding.

10. The decoding device according to claim 9, wherein

the high frequency signal generating unit calculates an estimated value of the second sub-band power based on a feature amount acquired from a low frequency signal obtained from the decoding and the estimating coefficient, and generates a high frequency signal based on the estimated value of the second sub-band power and the low frequency signal obtained from the decoding.

11. The decoding device according to claim 10, further comprising a high frequency decoding unit configured to decode the data and obtain the estimating coefficient.

12. The decoding device according to claim 10, wherein

pseudo high frequency sub-band power which is an estimated value of the second sub-band power is calculated based on the input signal or the feature amount obtained from the low frequency signal of the input signal, and the data is generated by comparing the second sub-band power with the pseudo high frequency sub-band power.

13. The decoding device according to claim 12, wherein

the pseudo high frequency sub-band power is calculated based on the input signal or the feature amount obtained from low frequency signal of the input signal and the estimating coefficient preliminarily prepared, and the data to obtain any one of a plurality of the estimating coefficients is generated.

14. The decoding device according to claim 10, wherein

the second sub-band power is calculated by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m.

15. The decoding device according to claim 10, wherein

the second sub-band power is calculated by obtaining a weighted mean value of the first sub-band power, using the weight which becomes larger as the first sub-band power becomes larger.

16. A decoding method comprising steps of:

demultiplexing an input code string into data and low frequency encoded data, wherein the data is generated based on second sub-band power of a second sub-band signal including a number of the continuous first sub-bands on a high frequency side of an input signal, the second sub-band power is calculated by weighting more first sub-band power having larger power among first sub-band power of the first sub-bands and used for obtaining, by estimating, a high frequency signal of the input signal, and the low frequency encoded data is obtained by encoding the low frequency signal of the input signal;

decoding the low frequency encoded data to generate a low frequency signal;

generating a high frequency signal based on an estimating coefficient obtained from the data and the low frequency signal obtained from the decoding; and

generating an output signal based on the generated high frequency signal and the low frequency signal obtained from the decoding.

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

demultiplexing an input code string into data and low frequency encoded data, wherein the data is generated based on second sub-band power of a second sub-band signal including a number of the continuous first sub-bands on a high frequency side of an input signal, the second sub-band power is calculated by weighting more first sub-band power having larger power among first sub-band power of the first sub-bands and used for obtaining, by estimating, a high frequency signal of the input signal, and the low frequency encoded data is obtained by encoding the low frequency signal of the input signal;

decoding the low frequency encoded data to generate a low frequency signal;

generating a high frequency signal based on an estimating coefficient obtained from the data and the low frequency signal obtained from the decoding; and

generating an output signal based on the generated high frequency signal and the low frequency signal obtained from the decoding.