Parameter decoding apparatus and parameter decoding method
View Patent ↗A parameter decoding apparatus includes a prediction residue decoder that finds a quantized prediction residue based on encoded information included in a current frame subject to decoding and a moving-average predictor produces a predicted parameter by multiplying a predictive coefficient with a past quantized prediction residue. An adder decodes a parameter by adding the quantized prediction residue and the predicted parameter, wherein the prediction residue decoder, when the current frame is erased, finds a current-frame quantized prediction residue from a weighted linear sum of a parameter decoded in the past and a future-frame quantized prediction residue.
1. A parameter decoding apparatus that includes a processor connected to a memory, the parameter decoding apparatus comprising:
a prediction residue decoder that finds a quantized prediction residue based on encoded information included in a current frame subject to decoding,
a moving-average predictor that produces a predicted parameter by multiplying a predictive coefficient with a past quantized prediction residue; and
an adder that decodes a parameter by adding said quantized prediction residue and said predicted parameter,
wherein said prediction residue decoder, when said current frame is erased, finds a current-frame quantized prediction residue from a weighted linear sum of a parameter decoded in the past and a future-frame quantized prediction residue.
2. A parameter decoding apparatus according to claim 1 , wherein said prediction residue decoder, when said current frame is erased, finds a current-frame quantized prediction residue using the following equation;
x
[
n
]
=
β
0
x
[
n
+
1
]
+
∑
i
=
1
M
(
β
i
x
[
n
-
i
]
)
+
β
-
1
y
[
n
-
1
]
where;
β 0 , βi and β −1 are weighting coefficients vectors expressed by an MA predictive coefficient vector,
x[n] is quantized prediction residue vector of ISF parameter in the current frame,
x[n+1] is quantized prediction residue vector of ISF parameter in the next frame, and
y[n−1] is decoded ISF parameter in the previous frame.
3. A parameter decoding method comprising:
finding a quantized prediction residue based on encoding information included in a current frame subject to decoding,
producing a predicted parameter by multiplying a predictive coefficient with a past quantized prediction residue; and
decoding a parameter by adding said quantized prediction residue and said predicted parameter,
wherein, in the finding, when said current frame is erased, a current-frame quantized prediction residue is found from a weighted linear sum of a parameter decoded in the past and a future-frame quantized prediction residue, and
wherein at least one of the finding, the producing and the decoding is performed by a processor.
4. A parameter decoding method according to claim 3 , wherein, in the finding, when said current frame is erased, a current-frame quantized prediction residue is found from the following equation;
x
[
n
]
=
β
0
x
[
n
+
1
]
+
∑
i
=
1
M
(
β
i
x
[
n
-
i
]
)
+
β
-
1
y
[
n
-
1
]
where;
β 0 , β i and β −1 are weighting coefficients vectors expressed by an MA predictive coefficient vector,
x[n] is quantized prediction residue vector of ISF parameter in the current frame,
x[n+1] is quantized prediction residue vector of ISF parameter in the next frame, and
y[n−1] is decoded ISF parameter in the previous frame.