Encoding device and method, decoding device and method, and program

• US 9,361,900 B2
• Filed: 08/14/2012
• Issued: 06/07/2016
• 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
• Primary Examiner(s): Singh, Satwant
• Application Number:
  US14/237,990
• Publication Number:
  US 20140200900A1
• Time in Patent Office: 1,393 Days
• Field of Search: None
• US Class Current: 1/1
• 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:

circuitry 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;

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

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 by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m;

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

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

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

2. The encoding device according to claim 1, wherein the circuitry is further 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, and

generate 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 circuitry is further configured to:

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

generate the data to obtain any one of a plurality of the estimating coefficients.

4. The encoding device according to claim 3, wherein the circuitry is further configured to:

generate high frequency encoded data by encoding the data, and

multiplex 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 circuitry is further configured to calculate 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.

6. The encoding device according to claim 1, wherein the circuitry comprises a central processing unit.

7. A computer-implemented 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 by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m;

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 non-transitory computer-readable medium storing instructions that, when executed by a computer, cause the computer to execute 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 by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m;

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:

circuitry 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, the second sub-band power being calculated by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m;

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

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

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 circuitry is further configured to:

calculate 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

generate 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, wherein the circuitry is further configured to decode the data and obtain the estimating coefficient.

12. The decoding device according to claim 10, wherein the circuitry is further 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 the feature amount obtained from the low frequency signal of the input signal, and

generate the data 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 circuitry is further configured to:

calculate the pseudo high frequency sub-band power 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

generate the data to obtain any one of a plurality of the estimating coefficients.

14. The decoding device according to claim 10, wherein the circuitry is further configured to:

calculate 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.

15. The decoding device according to claim 9, wherein the circuitry comprises a central processing unit.

16. A computer-implemented 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, the second sub-band power being calculated by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m;

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 non-transitory computer-readable medium storing instructions that, when executed by a computer, cause the computer to execute 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, the second sub-band power being calculated by raising a mean value of the first sub-band power raised by the exponent of m by the exponent of 1/m;

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.