US2013218557A1PendingUtilityA1
Adaptive Approach to Improve G.711 Perceptual Quality
Est. expiryOct 4, 2027(~1.2 yrs left)· nominal 20-yr term from priority
Inventors:Yang Gao
G10L 19/26H04B 14/04G10L 21/0208
48
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
In order to achieve the best improvement of ITU G.711 related codec perceptual quality, perceptual weighting controlling parameter(s) should be at least adaptive to relative quantization error statistics or adaptive to signal level. When the relative quantization error statistics are larger or the signal level is lower, the perceptual weighting should be “stronger”; when the relative quantization error statistics are smaller or the signal level is larger, the perceptual weighting should be “weaker”.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A method for improving a perceptual weighting filter W(z) or a perceptual noise shaping filter F(z), wherein F(z)=W(z)−1, and the weighting filter W(z) or the perceptual noise shaping filter F(z) is used to enhance perceptual performance of a G.711 codec, the method comprising:
receiving, by the G.711 codec, an unquantized signal;
encoding, by the G.711 codec, said unquantized signal to produce an encoded bitstream; and
sending, by the G.711 codec, the encoded bitstream to a decoder for outputting an enhanced decoded signal;
wherein the unquantized signal is encoded using the W(z) or the F(z) as follows:
W
(
z
)
=
A
(
z
/
α
)
=
1
+
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
F
(
z
)
=
W
(
z
)
-
1
=
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing an input signal, {α 1 , i=1,2, . . . , P} are the LP predictor coefficients, P is the LP predictor order and α is a controlling parameter controlling the W(z) or the F(z),
and wherein the controlling parameter a depends on an input signal level, when the input signal level becomes low (towards zero), a approaches 0.
2 . The method of claim 1 , wherein the G.711 codec performs as a core layer of a scalable encoder.
3 . The method of claim 1 , wherein the G.711 codec is compatible with International Telecommunication Union (ITU) G.711 A-law or μ-law codec standard.
4 . A method for improving a perceptual weighting filter W(z) or a perceptual noise shaping filter F(z), wherein F(z)=W(z)−1, and the weighting filter W(z) or the perceptual noise shaping filter F(z) is used to enhance perceptual performance of a G.711 codec, the method comprising:
receiving, by the G. 711 codec, an unquantized signal;
encoding, by the G. 711 codec, said unquantized signal using the W(z) or the F(z) to produce an encoded bitstream; and
sending, by the G. 711 codec, the encoded bitstream to a decoder for outputting an enhanced decoded signal;
wherein the W(z) or the F(z) is characterized as follows:
the W(z) or the F(z) is controlled by one or more parameters; and
at least one of the parameters controls the W(z) or the F(z) based on an input signal level, and when the input signal level becomes low (towards zero), the W(z) approaches 1 or equivalently the F(z) approaches 0.
5 . The method of claim 4 , wherein the perceptual weighting filter W(z) or the perceptual noise shaping filter F(z) is defined by the following equations:
W
(
z
)
=
A
(
z
/
α
)
=
1
+
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
F
(
z
)
=
W
(
z
)
-
1
=
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing the input signal, {α 1 , i=1,2, . . . , P} are the LP predictor coefficients, P is the LP predictor order and a is the controlling parameter controlling the W(z) or the F(z).
6 . The method of claim 4 , wherein the perceptual weighting filter W(z) or the perceptual noise shaping filter F(z) is defined by the following equations:
W
(
z
)
=
A
(
z
/
α
)
A
(
z
/
β
)
F
(
z
)
=
W
(
z
)
-
1
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing the input signal; {α i , i =1,2, . . . , P} are the LP predictor coefficients; P is the LP predictor order; α and β (β<α) are the controlling parameters controlling the W(z) or the F(z).
7 . The method of claim 4 , wherein the perceptual weighting filter W(z) or the perceptual noise shaping filter F(z) is defined by the following equations:
W
(
z
)
=
A
(
z
/
α
)
1
+
β
·
z
-
1
F
(
z
)
=
W
(
z
)
-
1
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing the input signal; {α i , i=1,2, . . . , P} are the LP predictor coefficients; P is the LP predictor order; α and β (β<α) are the controlling parameters controlling the W(z) or the F(z).
8 . The method of claim 4 , wherein the G.711 encoder performs as a core layer of a scalable encoder.
9 . The method of claim 4 , wherein the G.711 encoder is compatible with International Telecommunication Union (ITU) G.711 A-law or μ-law codec standard.
10 . A codec, comprising:
a receiving unit, configured to receive an unquantized signal; an encoding unit, configured to encode said unquantized signal to produce an encoded bitstream; and a sending unit, configured to send the encoded bitstream to a decoder for outputting an enhanced decoded signal;
wherein the unquantized signal is encoded using a perceptual weighting filter W(z) or a perceptual noise shaping filter F(z), the W(z) or the F(z) is characterized as follows:
W
(
z
)
=
A
(
z
/
α
)
=
1
+
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
F
(
z
)
=
W
(
z
)
-
1
=
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing an input signal, {α i , i=1,2, . . . , P} are the LP predictor coefficients, P is the LP predictor order and α is a controlling parameter controlling the W(z) or the F(z),
and wherein the controlling parameter a depends on an input signal level, when the input signal level becomes low (towards zero), a approaches 0.
11 . The codec according to claim 10 , wherein the codec performs as a core layer of a scalable encoder.
12 . The codec according to claim 10 , wherein the codec is compatible with International Telecommunication Union (ITU) G.711 A-law or β-law codec standard.
13 . A codec, comprising:
a receiving unit, configured to receive an unquantized signal; an encoding unit, configured to encode said unquantized signal to produce an encoded bitstream; and a sending unit, configured to send the encoded bitstream to a decoder for outputting an enhanced decoded signal;
wherein the unquantized signal is encoded using a perceptual weighting filter W(z) or a perceptual noise shaping filter F(z), wherein F(z)=W(z)−1, and the W(z) or the F(z) is characterized as follows:
the W(z) or the F(z) is controlled by one or more parameters; and
at least one of the parameters controls the W(z) or the F(z) based on an input signal level, and when the input signal level becomes low (towards zero), the W(z) approaches 1 or equivalently the F(z) approaches 0.
14 . The codec according to claim 13 , wherein the perceptual weighting filter W(z) or the perceptual noise shaping filter F(z) is defined by the following equations:
W
(
z
)
=
A
(
z
/
α
)
=
1
+
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
F
(
z
)
=
W
(
z
)
-
1
=
∑
i
=
1
P
a
i
·
α
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing the input signal, {α i , i=1,2, . . . , P} are the LP predictor coefficients, P is the LP predictor order and α is the controlling parameter controlling the W(z) or the F(z).
15 . The codec according to claim 13 , wherein the perceptual weighting filter W(z) or the perceptual noise shaping filter F(z) is defined by the following equations:
W
(
z
)
=
A
(
z
/
α
)
A
(
z
/
β
)
F
(
z
)
=
W
(
z
)
-
1
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing the input signal; {α i , i=1,2, . . . , P} are the LP predictor coefficients; P is the LP predictor order; α and β (β<α) are the controlling parameters controlling the W(z) or the F(z).
16 . The codec according to claim 13 , wherein the perceptual weighting filter W(z) or the perceptual noise shaping filter F(z) is defined by the following equations:
W
(
z
)
=
A
(
z
/
α
)
1
+
β
·
z
-
1
F
(
z
)
=
W
(
z
)
-
1
A
(
z
)
=
1
+
∑
i
=
1
P
a
i
·
z
-
i
,
i
=
1
,
2
,
…
,
P
where A(z) is a linear prediction (LP) predictor obtained from analyzing the input signal; {α i , i=1,2, . . . , P}are the LP predictor coefficients; P is the LP predictor order; α and β (β<α) are the controlling parameters controlling the W(z) or the F(z).
17 . The codec according to claim 13 , wherein the codec performs as a core layer of a scalable encoder.
18 . The codec according to claim 13 , wherein the codec is compatible with International Telecommunication Union (ITU) G.711 A-law or μ-law codec standard.Cited by (0)
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