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US 12,217,764 B2Granted
Encoding method, decoding method, encoding apparatus, and decoding apparatus
AssigneeHuawei Technologies Co., Ltd.
InventorsBin Wang, Zexin Liu, Lei Miao
Life of this patent
Estimating the term…
Abstract
An encoding method includes dividing a to-be-encoded time-domain signal into a low band signal and a high band signal, performing encoding on the low band signal to obtain a low frequency encoding parameter, performing encoding on the high band signal to obtain a high frequency encoding parameter, obtaining a synthesized high band signal, performing short-time post-filtering processing on the synthesized high band signal to obtain a short-time filtering signal, and calculating a high frequency gain based on the high band signal and the short-time filtering signal.
Claims14
An encoding method, comprising:
- dividing an input time domain signal into a low band signal and a high band signal;
- encoding, using an algebraic code excited linear prediction (ACELP) encoder, the low band signal to obtain a low frequency encoding parameter;
- obtaining an excitation signal according to the low frequency encoding parameter;
- encoding the high band signal to obtain a high frequency encoding parameter;
- obtaining, by passing the excitation signal through a linear predictive coding (LPC) synthesis filter, a synthesized high band signal, wherein coefficients of the LPC synthesis filter are based on the high frequency encoding parameter;
- performing, using a short-term post-filter, filtering processing on the synthesized high band signal to obtain a short-time filtered signal, wherein the short-term post-filter comprises a pole-zero filter, and wherein a coefficient of the pole-zero filter is based on the high frequency encoding parameter;
- calculating a z-domain transfer function of the pole-zero filter using the following formula:
- H
- s
- (
- z
- )
- =
- 1
- -
- a
- 1
-
- β
-
- z
- -
- 1
- -
- a
- 2
-
- β
- 2
-
- z
- -
- 2
- -
- …
- -
- a
- M
-
- β
- M
-
- z
- -
- M
- 1
- -
- a
- 1
-
- γ
-
- z
- -
- 1
- -
- a
- 2
-
- γ
- 2
-
- z
- -
- 2
- -
- …
- -
- a
- M
-
- γ
- M
-
- z
- -
- M
- ,
- wherein Hs(z) is the z-domain transfer function, wherein a1, a2, . . . aM is an LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ are constants that satisfy a condition 0<β<γ<1;
- and
- calculating a high frequency gain based on the high band signal and the short-time filtered signal.
78 more elements
A decoding method, comprising:
- obtaining a low frequency encoding parameter, a high frequency encoding parameter, and a high frequency gain from a bitstream;
- decoding, using an algebraic code excited linear prediction (ACELP) decoder, the low frequency encoding parameter to obtain a low band signal;
- obtaining an excitation signal according to the low frequency encoding parameter;
- obtaining a synthesized high band signal by passing the excitation signal through a linear predictive coding (LPC) synthesis filter, wherein coefficients of the LPC synthesis filter are based on the high frequency encoding parameter;
- performing, using a short-term post-filter, filtering processing on the synthesized high band signal to obtain a short-time filtered signal, wherein the short-term post-filter comprises a pole-zero filter, and wherein a coefficient of the pole-zero filter is based on the high frequency encoding parameter;
- calculating a z-domain transfer function of the pole-zero filter is calculated using the following formula:
- H
- s
- (
- z
- )
- =
- 1
- -
- a
- 1
-
- β
-
- z
- -
- 1
- -
- a
- 2
-
- β
- 2
-
- z
- -
- 2
- -
- …
- -
- a
- M
-
- β
- M
-
- z
- -
- M
- 1
- -
- a
- 1
-
- γ
-
- z
- -
- 1
- -
- a
- 2
-
- γ
- 2
-
- z
- -
- 2
- -
- …
- -
- a
- M
-
- γ
- M
-
- z
- -
- M
- ,
- wherein Hs(z) is the z-domain transfer function, wherein a1, a2, . . . aM is an LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ are constants that satisfy a condition 0<β<γ<1;
- adjusting the short-time filtered signal using the high frequency gain to obtain a high band signal;
- and
- combining the low band signal and the high band signal to obtain a final decoding signal.
78 more elements
An encoding apparatus, comprising:
- a memory comprising instructions;
- and
- a processor coupled to the memory and configured to execute the instructions to cause the encoding apparatus to:
- divide an input time domain signal into a low band signal and a high band signal;
- encode, using an algebraic code excited linear prediction (ACELP) encoder, the low band signal to obtain a low frequency encoding parameter;
- obtain an excitation signal according to the low frequency encoding parameter;
- encode the high band signal to obtain a high frequency encoding parameter;
- obtain a synthesized high band signal by passing the excitation signal through a linear predictive coding (LPC) synthesis filter, wherein coefficients of the LPC synthesis filter are based on the high frequency encoding parameter;
- perform, using a short-term post-filter, filtering processing on the synthesized high band signal to obtain a short-time filtered signal, wherein the short-term post-filter comprises a pole-zero filter, and wherein a coefficient of the pole-zero filter is based on the high frequency encoding parameter;
- calculate a z-domain transfer function of the pole-zero filter is calculated using the following formula:
- H
- s
- (
- z
- )
- =
- 1
- -
- a
- 1
-
- β
-
- z
- -
- 1
- -
- a
- 2
-
- β
- 2
-
- z
- -
- 2
- -
- …
- -
- a
- M
-
- β
- M
-
- z
- -
- M
- 1
- -
- a
- 1
-
- γ
-
- z
- -
- 1
- -
- a
- 2
-
- γ
- 2
-
- z
- -
- 2
- -
- …
- -
- a
- M
-
- γ
- M
-
- z
- -
- M
- ,
- wherein Hs(z) is the z-domain transfer function, wherein a1, a2, . . . aM is an LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ are constants that satisfy a condition 0<β<γ<1;
- and
- calculate a high frequency gain based on the high band signal and the short-time filtered signal.
81 more elements
Dependencies are inferred from the claim text.