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

Patent metadata

Field	Value
Publication number	US-9842603-B2
Application number	US-201214236350-A
Country	US
Kind code	B2
Filing date	Aug 14, 2012
Priority date	Aug 24, 2011
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

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.

First claim

The invention claimed is:

1. An encoding device, comprising:
processing circuitry configured to perform a process including:
receiving an input audio signal;
generating a low frequency sub-band signal of a sub-band on a low frequency side of the input audio signal and a high frequency sub-band signal of a sub-band on a high frequency side of the input audio 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 by calculating a sub-band power sum of the power of the sub-band signal of the sub-bands on the high frequency side of the input signal, wherein the sub-band power sum is an estimated bandwidth of a frame to be processed;
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;
encoding a low frequency signal of the input signal to generate low frequency encoded data;
multiplexing the data and the low frequency encoded data to generate an output code string representative of the input audio signal; and
outputting the 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 temporal change of 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 frequency profile of the input signal.

4. 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.

5. The encoding device according to claim 1 , further comprising the processing circuitry calculating, 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 includes selecting 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.

6. The encoding device according to claim 5 , 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.

7. The encoding device according to claim 5 , wherein the selecting includes selecting 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, identifying 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 defining the estimation coefficient selected in each frame as the estimation coefficient of the corresponding frame in the identified combination.

8. The encoding device according to claim 1 , further comprising the processing circuitry encoding the data to generate high frequency encoded data, wherein
the multiplexing includes generating the output code string by multiplexing the high frequency encoded data and the low frequency encoded data.

9. The encoding device according to claim 8 , wherein
the determining includes calculating 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 includes encoding 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.

10. An encoding method, comprising:
receiving, by processing circuitry, an input audio signal;
generating, by the processing circuitry, a low frequency sub-band signal of a sub-band on a low frequency side of the input audio signal and a high frequency sub-band signal of a sub-band on a high frequency side of the input audio signal;
calculating, by the processing circuitry, 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, by the processing circuitry, a number-of-sections determining feature amount by calculating a sub-band power sum of the power of the sub-band signal of the sub-bands on the high frequency side of the input signal, wherein the sub-band power sum is an estimated bandwidth of a frame to be processed;
determining, by the processing circuitry, 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, by the processing circuitry, 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, by the processing circuitry, data for obtaining the estimation coefficient selected in a frame of each of the continuous frame sections constituting the process target section;
generating, by the processing circuitry, low frequency encoded data by encoding a low frequency signal of the input signal;
generating, by the processing circuitry, an output code string by multiplexing the data and the low frequency encoded data, the output code string being representative of the input audio signal; and
outputting, by the processing circuitry, the output code string.

11. A computer-readable storage device encoded with computer-executable instructions that, when executed by processing circuitry, perform an encoding method comprising:
receiving an input audio signal;
generating a low frequency sub-band signal of a sub-band on a low frequency side of the input audio signal and a high frequency sub-band signal of a sub-band on a high frequency side of the input audio 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 c

Assignees

• Yamamoto Yuki
• Chinen Toru
• Sony Corp

Inventors

• Yamamoto Yuki
• Chinen Toru

Classifications

• G10L21/038

  using band spreading techniques · CPC title

• G10L19/0204 Primary

  using subband decomposition · CPC title

• G10L19/022

  Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring · CPC title

• G10L19/265 Primary

  Pre-filtering, e.g. high frequency emphasis prior to encoding · CPC title

• G10L25/21

  the extracted parameters being power information · CPC title