Data processing method and device for processing speech signal or audio signal
A data processing method is disclosed, including: twiddling input data, so as to obtain twiddled data; pre-rotating the twiddled data by using a symmetric rotate factor, where the rotate factor is a·W 4L 2p+1 , p=0, . . . , L/2−1, and a is a constant; performing a Fast Fourier (Fast Fourier Transform, FFT) transform of L/2 point on the pre-rotated data, where L is the length of the input data; post-rotating the data that has undergone the FFT transform by using a symmetric rotate factor, where the rotate factor is b·W 4L 2q+1 , q=0, . . . , L/2−1, and b is a constant; and obtaining output data.
1. A method for processing a raw audio signal to transform the raw audio signal from time domain to frequency or from frequency domain to time domain and performed by an audio signal processing device including a processor, comprising:
obtaining an input signal corresponding to the raw audio signal;
obtaining a twiddled signal by twiddling the input signal;
pre-rotating the twiddled signal by using a first symmetric rotate factor to generate a pre-rotated signal, wherein the first symmetric rotate factor is (a·W 4L 2p+1 ), wherein p=0, . . . , L/2−1, and (a) is a constant;
performing a Fast Fourier Transform (FFT) of a L/2 point on the pre-rotated signal to generate a FFT transformed signal, wherein L is the length of the input signal;
post-rotating the FFT transformed signal using a second symmetric rotate factor to generate a post-rotated signal, wherein the second symmetric rotate factor is (b·W 4L 2q+1 ), wherein q=0, . . . , L/2−1, and wherein (b) is a constant; and
writing a processed audio signal based on the post-rotated signal into a bitstream for transmitting or storing.
2. The method according to claim 1 , before the post-rotating step, the method further comprises performing fixed rotate compensation by using a fixed rotate compensation factor.
3. The method according to claim 2 , wherein performing the fixed rotate compensation by using the fixed rotate compensation factor comprises:
performing fixed rotate compensation at least one time, wherein a product of a rotate compensation factor of the at least one time fixed rotate compensation is W 8L −3 .
4. The method according to claim 2 , wherein performing the fixed rotate compensation by using the fixed rotate compensation factor comprises:
performing fixed rotate compensation at least one time, wherein a rotate compensation factor of the at least one time fixed rotate compensation is a first order Taylor series expansion of at least one factor a product of which is W 8L −3 .
5. The method according to claim 1 , wherein a product of (a) and (b) is equal to
2
2
L
2
.
6. A time-domain to frequency-domain signal processing method for processing a raw audio signal performed by an audio signal processing device comprising a processor, comprising:
obtaining a time domain signal corresponding to the raw audio signal;
obtaining a pre-processed signal by pre-processing the time domain signal;
pre-rotating the pre-processed signal by using a rotate factor (a·W N n+0.5 ) to generate a pre-rotated signal;
performing a Fast Fourier Transform (FFT) of N/4 point on the pre-rotated signal to generate a FFT transformed signal;
post-rotating the FFT transformed signal using a rotate factor (b·W N k+0.5 ), so as to obtain a frequency domain signal;
writing a processed audio signal based on the frequency domain signal into a bitstream for transmitting or storing;
wherein, before the obtaining the frequency domain signal, the method further comprises performing fixed rotate compensation by using a fixed rotate compensation factor; (a) and (b) are constants, the N is the length of the time domain signal, and
W
N
=
ⅇ
-
j
2
π
N
.
7. The method according to claim 6 , wherein performing the fixed rotate compensation by using the fixed rotate compensation factor comprises:
performing fixed rotate compensation at least one time, wherein a product of a rotate compensation factor of the at least one time fixed rotate compensation is W N −0.75 .
8. The method according to claim 6 , wherein performing the fixed rotate compensation by using the fixed rotate compensation factor comprises:
performing fixed rotate compensation at least one time, wherein a rotate compensation factor of the at least one time fixed rotate compensation is a first order Taylor series expansion of at least one factor a product of which is W N −0.75 .
9. The method according to claim 1 , wherein a product of (a) and (b) is equal to
2
N
.
10. A frequency-domain to time-domain signal processing method for processing a raw audio signal performed by an audio signal processing device including a processor, comprising:
obtaining a frequency domain signal corresponding to the raw audio signal;
obtaining a twiddled signal by twiddling the frequency domain signal;
pre-rotating the twiddled signal by using a rotate factor (c·W N k+0.5 ) to generate a pre-rotated signal;
performing a Fast Fourier Transform (FFT) of N/4 point on the pre-rotated signal to generate a FFT transformed signal;
post-rotating the FFT transformed signal using a rotate factor (d·W N n+0.5 ) to generate a post-rotated signal;
post-processing the post-rotated signal, so as to obtain a time domain signal; and
obtaining a processed audio audio signal based on the post-rotated signal;
wherein, before obtaining the time domain signal, the method further comprises performing fixed rotate compensation by using a fixed rotate compensation factor; (c) and (d) are constants, the N is twice the length of the frequency domain signal, and
W
N
=
ⅇ
-
j
2
π
N
.
11. The method according to claim 10 , wherein performing the fixed rotate compensation by using the fixed rotate compensation factor comprises:
performing fixed rotate compensation at least one time, wherein a product of a rotate compensation factor of the at least one time fixed rotate compensation is W N −0.75 .
12. The method according to claim 10 , wherein performing the fixed rotate compensation by using the fixed rotate compensation factor comprises:
performing fixed rotate compensation at least one time, wherein a rotate compensation factor of the at least one time fixed rotate compensation is a first order Taylor series expansion of at least one factor a product of which is W N −0.75 .
13. A signal processing device for processing a raw audio signal to transform the raw audio signal from time domain to frequency or from frequency domain to time domain and including a processor, comprising:
a unit configured to obtain an input signal corresponding to the raw audio signal;
a twiddle unit, configured to twiddle the input signal, so as to obtain a twiddled signal;
a pre-rotate unit, configured to pre-rotate the twiddled signal by using a first symmetric rotate factor to generate a pre-rotated signal, wherein the first symmetric rotate factor is (a·W 4L 2p+1 ), wherein p=0, . . . , L/2−1, and (a) is a constant;
a transform unit, configured to perform a Fast Fourier Transform (FFT) of L/2 point on the pre-rotated signal to generate a FFT transformed signal, wherein L is the length of the input signal;
a post-rotate unit, configured to post-rotate the FFT transformed signal using a second symmetric rotate factor to generate a post-rotated signal, wherein the second symmetric rotate factor is (b·W 4 2q+1 ), wherein q=0, . . . , L/2−1, and wherein (b) is a constant; and
a unit configured to write a processed audio signal based on the post-rotated signal into a bitstream for transmitting or storing.
14. The device according to claim 13 , further comprising:
a fixed rotate compensation unit, configured to perform fixed rotate compensation by using a fixed rotate compensation factor.
15. The device according to claim 14 , wherein the fixed rotate compensation unit is configured to perform fixed rotate compensation at least one time, and a product of a rotate compensation factor of the at least one time fixed rotate compensation is W 8L −3 .
16. The device according to claim 14 , wherein the fixed rotate compensation unit is configured to perform fixed rotate compensation at least one time, and a rotate compensation factor of the at least one time fixed rotate compensation is a first order Taylor series expansion of at least one factor a product of which is W 8L −3 .
17. The device according to claim 14 , wherein a product of (a) and (b) is equal to
2
2
L
2
.
18. A time-domain to frequency-domain signal processing device for processing a raw audio signal and including a processor, comprising:
a unit configured to obtain a time domain signal corresponding to the raw audio signal;
a pre-processing unit, configured to pre-process the time domain signal, so as to obtain a pre-processed signal;
a pre-rotate unit, configured to pre-rotate the pre-processed signal by using a rotate factor (a· N n+0.5 ) to generate a pre-rotated signal;
a transform unit, configured to perform a Fast Fourier Transform (FFT) of N/4 point on the pre-rotated signal to generate a FFT transformed signal;
a post-rotate unit, configured to post-rotate the FFT transformed signal using a rotate factor (b·W N k+0.5 ), so as to obtain a frequency domain signal;
a unit configured to write a processed audio signal based on the frequency domain signal into a bitstream for transmitting or storing;
wherein, the device further comprises:
a fixed compensation unit, configured to perform fixed rotate compensation by using a fixed rotate compensation factor; the (a) and (b) are constants, the N is the length of the time domain signal, and
W
N
=
ⅇ
-
j
2
π
N
.
19. The device according to claim 18 , wherein the fixed rotate compensation unit is configured to perform fixed rotate compensation at least one time, and a product of a rotate compensation factor of the at least one time fixed rotate compensation is W N −0.75 .
20. The device according to claim 18 , wherein the fixed rotate compensation unit is configured to perform fixed rotate compensation at least one time, and a rotate compensation factor of the at least one time fixed rotate compensation is a first order Taylor series expansion of at least one factor a product of which is W N −0.75 .
21. A frequency-domain to time-domain signal processing device for processing a raw audio signal and including a processor, comprising:
a unit configured to obtain a frequency domain signal corresponding to the raw audio signal;
a twiddle unit, configured to twiddle the frequency domain signal, so as to obtain a twiddled signal;
a pre-rotate unit, configured to pre-rotate the twiddled signal by using a rotate factor (c·W N k+0.5 ) to generate a pre-rotated signal;
a transform unit, configured to perform a Fast Fourier Transform (FFT) of N/4 point on the pre-rotated signal to generate a FFT transformed signal;
a post-rotate unit, configured to post-rotate the FFT transformed signal using a rotate factor (d·W N n+0.5 );
a unit configured to obtain a processed audio signal based on the post-rotated signal;
wherein, the device further comprises:
a fixed compensation unit, configured to perform fixed rotate compensation by using a fixed rotate compensation factor; the (c) and (d) are constants, the N is twice the length of the frequency domain signal, and
W
N
=
ⅇ
-
j
2
π
N
.
22. The device according to claim 21 , wherein the fixed rotate compensation unit is configured to perform fixed rotate compensation at least one time, and a product of a rotate compensation factor of the at least one time fixed rotate compensation is W N −0.75 .
23. The device according to claim 21 , wherein the fixed rotate compensation unit is configured to perform fixed rotate compensation at least one time, and a rotate compensation factor of the at least one time fixed rotate compensation is a first order Taylor series expansion of at least one factor a product of which is W N −0.75 .
24. A time-domain to frequency-domain audio signal processing method, with the audio signal processing being performed by an audio signal processing device including a processor, comprising:
obtaining a time domain signal corresponding to a raw audio signal;
applying at least one twiddle factor to the time domain signal to obtain a twiddled signal;
pre-rotating, by using a symmetric rotation factor (a·W 4L 2p+1 ), the twiddled signal to obtain a pre-rotated signal, wherein p=0, . . . , L/2−1, and (a) is a constant;
performing a Fast Fourier Transform (FFT) of L/2 points on the pre-rotated signal to obtain a FFT transformed signal;
performing a fixed rotate compensation to the FFT transformed signal by multiplying the FFT transformed signal with a fixed rotate compensation factor;
post-rotating the FFT transformed signal using a symmetric rotate factor (b·W 4L 2q+1 ) to obtain a post-rotated signal, wherein q=0, . . . , L/2−1, and (b) is a constant;
writing a processed audio signal based on the post-rotated signal into a bitstream for transmitting or storing.
25. A time-domain to frequency-domain audio signal processing apparatus, comprising:
a processor; and
memory coupled to the processor and including non-transitory computer-readable instructions that, when executed by the processor:
obtain a time domain signal corresponding to a raw audio signal;
apply twiddle factors to the time domain signal to obtain a twiddled signal;
pre-rotate, by using a symmetric rotation factor (a·W 4L 2p+1 ), the twiddled signal to obtain a pre-rotated signal, wherein p=0, . . . , L/2−1, and (a) is a constant;
perform a Fast Fourier Transform (FFT) of L/2 points on the pre-rotated signal to obtain a FFT transformed signal;
perform a fixed rotate compensation to the FFT transformed signal by multiplying the FFT transformed signal with a fixed rotate compensation factor;
post-rotate the FFT transformed signal using a symmetric rotate factor (b·W 4L 2q+1 ) to obtain a post-rotated signal, wherein q=0, . . . , L/2−1, and (b) is a constant;
write a processed audio signal based on the post-rotated signal into a bitstream for transmitting or storing.
26. The method according to claim 1 , wherein W 4L 2p+1 in the first symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
27. The method according to claim 1 , wherein W 4L 2q+1 in the second symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
28. The method according to claim 13 , wherein W 4L 2p+1 in the first symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
29. The method according to claim 13 , wherein W 4L 2q+1 in the second symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
30. The method according to claim 24 , wherein W 4L 2p+1 in the first symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
31. The method according to claim 24 , wherein W 4L 2q+1 the second symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
32. The method according to claim 25 , wherein W 4L 2p+1 in the first symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.
33. The method according to claim 25 , wherein W 4L 2q+1 in the second symmetric rotate factor is expressed in the following form:
W
4
L
2
p
+
1
=
cos
2
π
(
2
p
+
1
)
4
L
-
j
sin
2
π
(
2
p
+
1
)
4
L
.