Frequency domain parameter sequence generating method, encoding method, decoding method, frequency domain parameter sequence generating apparatus, encoding apparatus, decoding apparatus, program, and recording medium
First Claim
1. A frequency domain parameter sequence generating method, implemented by a frequency domain parameter sequence generating apparatus having processing circuitry, comprising:
- where p is an integer equal to or greater than 1, a linear prediction coefficient sequence which is obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p], and ω
[1], ω
[2], . . . , ω
[p] are a frequency domain parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p],determining, by the processing circuitry, a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] using the frequency domain parameter sequence ω
[1], ω
[2], . . . , ω
[p] as input in a parameter sequence conversion step, whereinthe processing circuitry determines a value of each converted frequency domain parameter {tilde over (
)}ω
[i] (i=1, 2, . . . , p) in the converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] through linear transformation which is based on a relationship of values between ω
[i] and one or more frequency domain parameters adjacent to ω
[i].
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Abstract
The present invention reduces encoding distortion in frequency domain encoding compared to conventional techniques, and obtains LSP parameters that correspond to quantized LSP parameters for the preceding frame and are to be used in time domain encoding from coefficients equivalent to linear prediction coefficients resulting from frequency domain encoding. When p is an integer equal to or greater than 1, a linear prediction coefficient sequence which is obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p], and ω[1], ω[2], . . . , ω[p] are a frequency domain parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], an LSP linear transformation unit (300) determines the value of each converted frequency domain parameter {tilde over ( )}ω[i] (i=1, 2, . . . , p) in a converted frequency domain parameter sequence {tilde over ( )}w[1], {tilde over ( )}w[2], . . . , {tilde over ( )}ω[p] using the frequency domain parameter sequence ω[1], ω[2], . . . , ω[p] as input, through linear transformation which is based on the relationship of values between ω[i] and one or more frequency domain parameters adjacent to ω[i].
21 Citations
12 Claims
-
1. A frequency domain parameter sequence generating method, implemented by a frequency domain parameter sequence generating apparatus having processing circuitry, comprising:
-
where p is an integer equal to or greater than 1, a linear prediction coefficient sequence which is obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p], and ω
[1], ω
[2], . . . , ω
[p] are a frequency domain parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p],determining, by the processing circuitry, a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] using the frequency domain parameter sequence ω
[1], ω
[2], . . . , ω
[p] as input in a parameter sequence conversion step, whereinthe processing circuitry determines a value of each converted frequency domain parameter {tilde over (
)}ω
[i] (i=1, 2, . . . , p) in the converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] through linear transformation which is based on a relationship of values between ω
[i] and one or more frequency domain parameters adjacent to ω
[i]. - View Dependent Claims (5, 11, 12)
-
-
2. A frequency domain parameter sequence generating method, implemented by a frequency domain parameter sequence generating apparatus having processing circuitry, comprising:
-
where p is an integer equal to or greater than 1, and a linear prediction coefficient sequence obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p]; ω
[1], ω
[2], . . . , ω
[p] is one ofan LSP parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], an LSF parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], and a frequency domain parameter sequence which is derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p] and in which all of ω
[1], ω
[2], . . . , ω
[p] are present from 0 to π and
, when all of linear prediction coefficients contained in the linear prediction coefficient sequence are 0, ω
[1], ω
[2], . . . , ω
[p] are present from 0 to π
at equal intervals; andeach γ
1 and γ
2 is a adjustment factor which is a positive constant equal to or smaller than 1, and K is a predetermined pxp band matrix in which diagonal elements and elements that neighbor the diagonal elements in row direction have non-zero values,generating, by the processing circuitry, a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] defined by a following formula - View Dependent Claims (4)
-
-
3. A frequency domain parameter sequence generating method, implemented by a frequency domain parameter sequence generating apparatus having processing circuitry, comprising:
-
where p is an integer equal to or greater than 1, and a linear prediction coefficient sequence obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p]; ω
[1], ω
[2], . . . , ω
[p] is one ofan ISP parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], and an ISF parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p]; and each γ
1 and γ
2 is a adjustment factor which is a positive constant equal to or smaller than 1, and K is a predetermined p−
1×
p−
1 band matrix in which diagonal elements and elements that neighbor the diagonal elements in row direction have non-zero values,generating, by the processing circuitry, a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p−
1] defined by a following formula
-
-
6. A frequency domain parameter sequence generating apparatus comprising:
-
where p is an integer equal to or greater than 1, a linear prediction coefficient sequence which is obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p], and ω
[1], ω
[2], . . . , ω
[p] are a frequency domain parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p],a parameter sequence converting unit that determines a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] using the frequency domain parameter sequence ω
[1], ω
[2], . . . , ω
[p] as input, whereinthe parameter sequence converting unit determines a value of each converted frequency domain parameter {tilde over (
)}ω
[i] (i=1, 2, . . . , p) in the converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] through linear transformation which is based on a relationship of values between ω
[i] and one or more frequency domain parameters adjacent to ω
[i]. - View Dependent Claims (10)
-
-
7. A frequency domain parameter sequence generating apparatus comprising:
-
where p is an integer equal to or greater than 1, and a linear prediction coefficient sequence obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p]; ω
[1], ω
[2], . . . , ω
[p] is one ofan LSP parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], an LSF parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], and a frequency domain parameter sequence which is derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p] and in which all of ω
[1], ω
[2], . . . , ω
[p] are present from 0 to π and
, when all of linear prediction coefficients contained in the linear prediction coefficient sequence are 0, ω
[1], ω
[2], . . . , ω
[p] are present from 0 to it at equal intervals; andeach γ
1 and γ
2 is a adjustment factor which is a positive constant equal to or smaller than 1, and K is a predetermined p×
p band matrix in which diagonal elements and elements that neighbor the diagonal elements in row direction have non-zero values,a parameter sequence converting unit that generates a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p] defined by a following formula - View Dependent Claims (9)
-
-
8. A frequency domain parameter sequence generating apparatus comprising:
-
where p is an integer equal to or greater than 1, and a linear prediction coefficient sequence obtained by linear prediction analysis of audio signals in a predetermined time segment is represented as a[1], a[2], . . . , a[p]; ω
[1], ω
[2], . . . , ω
[p] is one ofan ISP parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p], and an ISF parameter sequence derived from the linear prediction coefficient sequence a[1], a[2], . . . , a[p]; and each γ
1 and γ
2 is a adjustment factor which is a positive constant equal to or smaller than 1, and K is a predetermined p−
1×
p−
1 band matrix in which diagonal elements and elements that neighbor the diagonal elements in row direction have non-zero values,a parameter sequence converting unit that generates a converted frequency domain parameter sequence {tilde over (
)}ω
[1], {tilde over (
)}ω
[2], . . . , {tilde over (
)}ω
[p−
1] defined by a following formula
-
Specification