ENCODING METHOD, DECODING METHOD, ENCODING DEVICE, DECODING DEVICE, PROGRAM, AND RECORDING MEDIUM

• US 20130101049A1
• Filed: 07/04/2011
• Published: 04/25/2013
• Est. Priority Date: 07/05/2010
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Fukui, Masahiro, Sasaki, Shigeaki, Hiwasaki, Yusuke, Koyama, Shoichi, Tsutsumi, Kimitaka
• Granted Patent: US 9,319,645 B2
• Time in Patent Office: Days
• US Class Current: 375/240.22
• CPC Class Codes: G10L 19/038 Vector quantisation, e.g. TwinVQ audio
• CPC Class Codes: H03M 7/3082 Vector coding for television signals, see H04N19/94
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/94 Vector quantisation

Abstract

In encoding, index information indicating a group of coefficients that minimizes the sum of the error between the value of each sample and the value obtained by multiplying the quantized value of the sample by a coefficient corresponding to the position of the sample, for all sample positions, among a plurality of groups of predetermined coefficients corresponding to the positions of the samples, is output. In decoding, a plurality of values corresponding to an input vector quantization index are obtained as decoded values corresponding to a plurality of sample positions;

and, with the use of a group of predetermined coefficients corresponding to the plurality of sample positions and indicated by input index information, the values obtained by multiplying the decoded values and the coefficients, corresponding to the sample positions are output.

Claims

1. An encoding method comprising:

a vector quantization step of vector-quantizing a plurality of samples collectively to obtain a vector quantization index and the quantized value of each of the plurality of samples; and

a coefficient group selection step of outputting index information indicating a group of coefficients that minimizes the sum of the error between the value of each sample and the value obtained by multiplying the quantized value of the sample by a coefficient corresponding to the position of the sample, for all sample positions, among a plurality of groups of predetermined coefficients corresponding to the positions of the samples.

2. The encoding method according to claim 1, wherein the groups of coefficients are each formed of coefficients disposed on a straight line in a plane having values corresponding to frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of each of the plurality of groups of coefficients are disposed in the plane on a straight line having a different gradient from straight lines for the other groups.

3. The encoding method according to claim 1, wherein the groups of coefficients are each formed of coefficients distributed lopsidedly on a straight line or a specific curve in a plane having values of frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of the plurality of groups of coefficients are disposed lopsidedly in the plane on straight lines that are not parallel to the first axis or specific curves.

4. The encoding method according to one of claims 1 to 3, wherein the number of bits of the index information output in the coefficient group selection step is equal to or smaller than the value obtained by subtracting the number of bits actually used for a code corresponding to the vector quantization index from the number of bits assigned for the code corresponding to the vector quantization index.

17. A computer-readable recording medium having stored thereon a program for causing a computer to execute the steps of the encoding method according to claim 1.

5. A decoding method comprising:

a vector decoding step of obtaining a plurality of values corresponding to an input vector quantization index as decoded values corresponding to a plurality of sample positions; and

a coefficient multiplication step of outputting, with the use of a group of predetermined coefficients corresponding to the plurality of sample positions and indicated by input index information, the values obtained by multiplying the decoded values and the coefficients, corresponding to the sample positions.

6. The decoding method according to claim 5, wherein the group of coefficients is formed of coefficients disposed on a straight line in a plane having values corresponding to frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of each of the plurality of groups of coefficients are disposed in the plane on a straight line having a different gradient from straight lines for the other groups.

7. The decoding method according to claim 5, wherein the group of coefficients is formed of coefficients distributed lopsidedly on a straight line or a specific curve in a plane having values of frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of the plurality of groups of coefficients are disposed lopsidedly in the plane on straight lines that are not parallel to the first axis or specific curves.

18. A computer-readable recording medium having stored thereon a program for causing a computer to execute the steps of the decoding method according to claim 5.

8. An encoding device comprising:

a vector quantizer that vector-quantizes a plurality of samples collectively to obtain a vector quantization index and the quantized value of each of the plurality of samples; and

a coefficient group selection unit that outputs index information indicating a group of coefficients that minimizes the sum of the error between the value of each sample and the value obtained by multiplying the quantized value of the sample by a coefficient corresponding to the position of the sample, for all sample positions, among a plurality of groups of predetermined coefficients corresponding to the positions of the samples.

9. The encoding device according to claim 8, wherein the groups of coefficients are each formed of coefficients disposed on a straight line in a plane having values corresponding to frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of each of the plurality of groups of coefficients are disposed in the plane on a straight line having a different gradient from straight lines for the other groups.

10. The encoding device according to claim 8, wherein the groups of coefficients are each formed of coefficients distributed lopsidedly on a straight line or a specific curve in a plane having values of frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of the plurality of groups of coefficients are disposed lopsidedly in the plane on straight lines that are not parallel to the first axis or specific curves.

11. The encoding device according to one of claims 8 to 10, wherein the number of bits of the index information output from the coefficient group selection unit is equal to or smaller than the value obtained by subtracting the number of bits actually used for a code corresponding to the vector quantization index from the number of bits assigned for the code corresponding to the vector quantization index.

12. A decoding device comprising:

a vector decoder that obtains a plurality of values corresponding to an input vector quantization index as decoded values corresponding to a plurality of sample positions; and

a coefficient multiplication unit that outputs, with the use of a group of predetermined coefficients corresponding to the plurality of sample positions and indicated by input index information, the values obtained by multiplying the decoded values and the coefficients, corresponding to the sample positions.

13. The decoding device according to claim 12, wherein the group of coefficients is formed of coefficients disposed on a straight line in a plane having values corresponding to frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of each of the plurality of groups of coefficients are disposed in the plane on a straight line having a different gradient from straight lines for the other groups.

14. The decoding device according to claim 12, wherein the group of coefficients is formed of coefficients distributed lopsidedly on a straight line or a specific curve in a plane having values of frequency or time corresponding to the sample positions with which the coefficients are associated on a first axis thereof and the values of the coefficients on a second axis thereof;

and

the coefficients of the plurality of groups of coefficients are disposed lopsidedly in the plane on straight lines that are not parallel to the first axis or specific curves.

15-16. -16. (canceled)