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

• US 20140200899A1
• 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 9,842,603 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• 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
• CPC Class Codes: G10L 25/21 the extracted parameters being power information

Abstract

The present technology relates to an encoding device and an encoding method, a decoding device and a decoding method, and a program, configured to obtain a high quality audio with less encoding amount. A number-of-sections determining feature amount calculating circuit calculates a number-of-sections determining feature amount for determining the number of divisions to divide a process target section into continuous frame sections each including a frame for which the same estimation coefficient is selected, based on sub-band signals of a plurality of sub-bands constituting an input signal. A quasi-high frequency sub-band power difference calculating circuit determines the number of continuous frame sections in the process target section based on the number-of-sections determining feature amount, selects an estimation coefficient for obtaining a high frequency component of the input signal by estimation for each continuous frame section, and generates data including a coefficient index for obtaining the estimation coefficient. A high frequency encoding circuit encodes the obtained data, and generates high frequency encoded data. The present technology can be applied to an encoding device.

Claims

1. An encoding device, comprising:

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

a quasi-high frequency sub-band power calculating unit configured to calculate a quasi-high frequency sub-band power that is an estimated value of a high frequency sub-band power of the high frequency sub-band signal based on the low frequency sub-band signal and a predetermined estimation coefficient;

a feature amount calculating unit configured to calculate a number-of-sections determining feature amount based on at least one of the low frequency sub-band signal or the high frequency sub-band signal;

a determining unit configured to determine the number of continuous frame sections including frames for which the same estimation coefficient is selected in a process target section including a plurality of frames of the input signal, based on the number-of-sections determining feature amount;

a selecting unit configured to select the estimation coefficient of a frame that constitutes the continuous frame section from a plurality of estimation coefficients based on the quasi-high frequency sub-band power and the high frequency sub-band power in each continuous frame section obtained by dividing the process target section based on the determined number of continuous frame sections;

a generating unit configured to generate data for obtaining the estimation coefficient selected in a frame of each of the continuous frame sections constituting the process target section;

a low frequency encoding unit configured to 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, wherein the number-of-sections determining feature amount includes a feature amount indicating a sum of the high frequency sub-band power.

3. The encoding device according to claim 1, wherein the number-of-sections determining feature amount includes a feature amount indicating a temporal change of a sum of the high frequency sub-band power.

4. The encoding device according to claim 1, wherein the number-of-sections determining feature amount includes a feature amount indicating a frequency profile of the input signal.

5. The encoding device according to claim 1, wherein the number-of-sections determining feature amount includes a linear sum or a nonlinear sum of a plurality of feature amounts.

6. The encoding device according to claim 1, further comprising an evaluation value sum calculating unit configured to calculate, based on an evaluation value indicating an error between the quasi-high frequency sub-band power and the high frequency sub-band power in the frame calculated for each of the estimation coefficients, a sum of the evaluation value of each frame constituting the continuous frame section for each of the estimation coefficients, wherein

the selecting unit is configured to select the estimation coefficient of the frame of the continuous frame section based on the sum of the evaluation value calculated for each of the estimation coefficients.

7. The encoding device according to claim 6, wherein each section obtained by equally dividing the process target section by the determined number of continuous frame sections is defined as the continuous frame section.

8. The encoding device according to claim 6, wherein the selecting unit is configured to select the estimation coefficient of the frame of the continuous frame section based on the sum of the evaluation value for each combination of divisions of the process target section that can be taken when dividing the process target section by the determined number of continuous frame sections, identify a combination with which the sum of the evaluation values of the selected estimation coefficients of all the frames constituting the process target section is minimized from among the combinations, and define the estimation coefficient selected in each frame as the estimation coefficient of the corresponding frame in the identified combination.

9. The encoding device according to claim 1, further comprising a high frequency encoding unit configured to encode the data to generate high frequency encoded data, wherein

the multiplexing unit is configured to generate the output code string by multiplexing the high frequency encoded data and the low frequency encoded data.

10. The encoding device according to claim 9, wherein

the determining unit is configured to further calculate an encoding amount of the high frequency encoded data of the process target section based on the determined number of continuous frame sections, and

the low frequency encoding unit is configured to encode the low frequency signal with an encoding amount determined from an encoding amount determined in advance for the process target section and the calculated encoding amount of the high frequency encoded data.

11. An encoding method, comprising the steps of:

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

calculating a quasi-high frequency sub-band power that is an estimated value of a high frequency sub-band power of the high frequency sub-band signal based on the low frequency sub-band signal and a predetermined estimation coefficient;

calculating a number-of-sections determining feature amount based on at least one of the low frequency sub-band signal or the high frequency sub-band signal;

determining the number of continuous frame sections including frames for which the same estimation coefficient is selected in a process target section including a plurality of frames of the input signal, based on the number-of-sections determining feature amount;

selecting the estimation coefficient of a frame that constitutes the continuous frame section from a plurality of estimation coefficients based on the quasi-high frequency sub-band power and the high frequency sub-band power in each continuous frame section obtained by dividing the process target section based on the determined number of continuous frame sections;

generating data for obtaining the estimation coefficient selected in a frame of each of the continuous frame sections constituting the process target section;

generating low frequency encoded data by encoding a low frequency signal of the input signal; and

generating an output code string by multiplexing the data and the low frequency encoded data.

12. A program configured to cause a computer to execute the steps of:

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

calculating a quasi-high frequency sub-band power that is an estimated value of a high frequency sub-band power of the high frequency sub-band signal based on the low frequency sub-band signal and a predetermined estimation coefficient;

calculating a number-of-sections determining feature amount based on at least one of the low frequency sub-band signal or the high frequency sub-band signal;

determining the number of continuous frame sections including frames for which the same estimation coefficient is selected in a process target section including a plurality of frames of the input signal, based on the number-of-sections determining feature amount;

selecting the estimation coefficient of a frame that constitutes the continuous frame section from a plurality of estimation coefficients based on the quasi-high frequency sub-band power and the high frequency sub-band power in each continuous frame section obtained by dividing the process target section based on the determined number of continuous frame sections;

generating data for obtaining the estimation coefficient selected in a frame of each of the continuous frame sections constituting the process target section;

generating low frequency encoded data by encoding a low frequency signal of the input signal; and

generating an output code string by multiplexing the data and the low frequency encoded data.

13. A decoding device, comprising:

a demultiplexing unit configured to demultiplex an input code string into data for obtaining an estimation coefficient selected in a frame of each continuous frame section constituting a process target section, which is generated based on a result of calculating an estimated value of a high frequency sub-band power of a high frequency sub-band signal of an input signal based on a low frequency sub-band signal of the input signal and a predetermined estimation coefficient, determining the number of continuous frame sections including frames for which the same estimation coefficient is selected in the process target section including a plurality of frames of the input signal based on a number-of-sections determining feature amount extracted from the input signal, and selecting the estimation coefficient of a frame constituting the continuous frame section from a plurality of estimation coefficients based on the estimated value and the high frequency sub-band power in each of the continuous frame sections obtained by dividing the process target section based on the determined number of continuous frame sections, and low frequency encoded data obtained by encoding a 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 the estimation coefficient obtained from the data and the low frequency signal obtained from the decoding; and

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

14. The decoding device according to claim 13, further comprising a high frequency decoding unit configured to decode the data to obtain the estimation coefficient.

15. The decoding device according to claim 14, wherein

based on an evaluation value indicating an error between the estimated value and the high frequency sub-band power in the frame calculated for each of the estimation coefficients, a sum of the evaluation value of each frame constituting the continuous frame section is calculated for each of the estimation coefficients, and

based on the sum of the evaluation value calculated for each of the estimation coefficients, the estimation coefficient of the frame of the continuous frame section is selected.

16. The decoding device according to claim 15, wherein each section obtained by equally dividing the process target section by the determined number of continuous frame sections is defined as the continuous frame section.

17. The decoding device according to claim 15, wherein

the estimation coefficient of the frame of the continuous frame section is selected based on the sum of the evaluation value for each combination of divisions of the process target section that can be taken when dividing the process target section by the determined number of continuous frame sections,

a combination with which the sum of the evaluation values of the selected estimation coefficients of all the frames constituting the process target section is minimized is identified from among the combinations, and

the estimation coefficient selected in each frame is defined as the estimation coefficient of the corresponding frame in the identified combination.

18. A decoding method, comprising the steps of:

demultiplexing an input code string into data for obtaining an estimation coefficient selected in a frame of each continuous frame section constituting a process target section, which is generated based on a result of calculating an estimated value of a high frequency sub-band power of a high frequency sub-band signal of an input signal based on a low frequency sub-band signal of the input signal and a predetermined estimation coefficient, determining the number of continuous frame sections including frames for which the same estimation coefficient is selected in the process target section including a plurality of frames of the input signal based on a number-of-sections determining feature amount extracted from the input signal, and selecting the estimation coefficient of a frame constituting the continuous frame section from a plurality of estimation coefficients based on the estimated value and the high frequency sub-band power in each of the continuous frame sections obtained by dividing the process target section based on the determined number of continuous frame sections, and low frequency encoded data obtained by encoding a low frequency signal of the input signal;

generating a low frequency signal by decoding the low frequency encoded data;

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

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

19. A program configured to cause a computer to execute the steps of:

demultiplexing an input code string into data for obtaining an estimation coefficient selected in a frame of each continuous frame section constituting a process target section, which is generated based on a result of calculating an estimated value of a high frequency sub-band power of a high frequency sub-band signal of an input signal based on a low frequency sub-band signal of the input signal and a predetermined estimation coefficient, determining the number of continuous frame sections including frames for which the same estimation coefficient is selected in the process target section including a plurality of frames of the input signal based on a number-of-sections determining feature amount extracted from the input signal, and selecting the estimation coefficient of a frame constituting the continuous frame section from a plurality of estimation coefficients based on the estimated value and the high frequency sub-band power in each of the continuous frame sections obtained by dividing the process target section based on the determined number of continuous frame sections, and low frequency encoded data obtained by encoding a low frequency signal of the input signal;

generating a low frequency signal by decoding the low frequency encoded data;

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

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