Coding device, decoding device, method, program and recording medium thereof
View Patent ↗A coding method and a decoding method are provided which can use in combination a predictive coding and decoding method which is a coding and decoding method that can accurately express coefficients which are convertible into linear prediction coefficients with a small code amount and a coding and decoding method that can obtain correctly, by decoding, coefficients which are convertible into linear prediction coefficients of the present frame if a linear prediction coefficient code of the present frame is correctly input to a decoding device. A coding device includes: a predictive coding unit that obtains a first code by coding a differential vector formed of differentials between a vector of coefficients which are convertible into linear prediction coefficients of more than one order of the present frame and a prediction vector containing at least a predicted vector from a past frame, and obtains a quantization differential vector corresponding to the first code; and a non-predictive coding unit that generates a second code by coding a correction vector which is formed of differentials between the vector of the coefficients which are convertible into the linear prediction coefficients of more than one order of the present frame and the quantization differential vector or formed of some of elements of the differentials.
1. A coding device comprising:
a predictive coding unit that obtains a first code by coding a differential vector formed of differentials between a vector of coefficients, which are convertible into linear prediction coefficients of more than one order obtained by performing linear prediction analysis on an input sound signal of a present frame, and a prediction vector containing at least a predicted vector from a past frame with respect to the coefficients convertible into linear prediction coefficients, and obtains a quantization differential vector with respect to the coefficients convertible into linear prediction coefficients, the quantization differential vector corresponding to the first code; and
a non-predictive coding unit that generates a second code by coding a correction vector which is formed of differentials between the vector of the coefficients, which are convertible into the linear prediction coefficients of more than one order obtained by performing linear prediction analysis on the input sound signal of the present frame, and the quantization differential vector with respect to the coefficients convertible into linear prediction coefficients or formed of some of elements of the differentials, wherein
the coding device outputs the first code and the second code.
2. A coding device comprising:
a predictive coding unit that obtains a first code by coding a differential vector formed of differentials between a vector of coefficients, which are convertible into linear prediction coefficients of more than one order obtained by performing linear prediction analysis on an input sound signal of a present frame, and a prediction vector formed of at least a prediction based on a past frame with respect to the coefficients convertible into linear prediction coefficients and a predetermined vector, and obtains a quantization differential vector with respect to the coefficients convertible into linear prediction coefficients, the quantization differential vector corresponding to the first code; and
a non-predictive coding unit that generates a second code by coding a correction vector which is formed of differentials obtained by subtracting the quantization differential vector with respect to the coefficients convertible into linear prediction coefficients and a predetermined vector from the vector of the coefficients, which are convertible into the linear prediction coefficients of more than one order obtained by performing linear prediction analysis on the input sound signal of the present frame, or formed of some of elements of the differentials, wherein
the coding device outputs the first code and the second code.
3. The coding device according to claim 2 , wherein
with an assumption that a is a positive constant, the prediction vector is a vector obtained by adding a predetermined lined predictive mean vector and what is obtained by multiplying a quantization differential vector of the past frame by a factor of α, and
the correction vector is a vector obtained by subtracting the quantization differential vector with respect to the coefficients convertible into linear prediction coefficients and a predetermined non-predictive mean vector from the vector of the coefficients which are convertible into the linear prediction coefficients of more than one order of the present frame or a vector formed of some of elements of that vector.
4. A coding method comprising:
a predictive coding step of obtaining a first code by coding a differential vector formed of differentials between a vector of coefficients, which are convertible into linear prediction coefficients of more than one order obtained by performing linear prediction analysis on an input sound signal of a present frame, and a prediction vector containing at least a predicted vector from a past frame with respect to the coefficients convertible into linear prediction coefficients, and obtaining a quantization differential vector with respect to the coefficients convertible into linear prediction coefficients, the quantization differential vector corresponding to the first code;
a non-predictive coding step of generating a second code by coding a correction vector which is formed of differentials between the vector of the coefficients, which are convertible into the linear prediction coefficients of more than one order obtained by performing linear prediction analysis on the input sound signal of the present frame, and the quantization differential vector with respect to the coefficients convertible into linear prediction coefficients or formed of some of elements of the differentials; and
an outputting step of outputting the first code and the second code.
5. A coding method comprising:
a predictive coding step of obtaining a first code by coding a differential vector formed of differentials between a vector of coefficients, which are convertible into linear prediction coefficients of more than one order obtained by performing linear prediction analysis on an input sound signal of a present frame, and a prediction vector formed of at least a prediction based on a past frame with respect to the coefficients convertible into linear prediction coefficients and a predetermined vector, and obtaining a quantization differential vector with respect to the coefficients convertible into linear prediction coefficients, the quantization differential vector corresponding to the first code;
a non-predictive coding step of generating a second code by coding a correction vector which is formed of differentials obtained by subtracting the quantization differential vector with respect to the coefficients convertible into linear prediction coefficients and a predetermined vector from the vector of the coefficients, which are convertible into the linear prediction coefficients of more than one order obtained by performing linear prediction analysis on the input sound signal of the present frame, or formed of some of elements of the differentials; and
an outputting step of outputting the first code and the second code.
6. A non-transitory recording medium having recorded thereon a program for making a computer function as the coding device according to claim 1 or 2 .