Linear Prediction Coefficient Coding With Error-Resilient Dual Vectors
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Solution Overview
Problem
Existing linear prediction coefficient decoding devices struggle with accurate decoding when transmission errors occur, leading to reduced sound quality and incorrect variable-length decoding due to the prioritization of minimizing code amount over error resilience.
Innovation Solution
A combined predictive and non-predictive coding/decoding method that generates and decodes differential vectors and correction vectors to ensure accurate expression of linear prediction coefficients, even in the presence of transmission errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vector coding using moving average prediction is used to reduce code amount, then code amount is reduced, but decoding accuracy deteriorates when transmission errors occur
Solution Approach 1:
The LSP parameter vector is segmented into two separate code vectors: a first code vector containing predictive coded differential vectors, and a second code vector containing non-predictive coded differential vectors. This segmentation allows the system to use both predictive coding (for efficiency) and non-predictive coding (for error resilience) simultaneously, resolving the contradiction between code amount reduction and decoding accuracy under transmission errors.
Solution Approach 2:
The system changes the coding parameter by introducing a dual-coding approach where different parts of the parameter vector are coded differently. The first code vector uses predictive coding with moving average prediction, while the second code vector uses non-predictive coding. This parameter change enables the system to achieve both small code amount and high decoding accuracy even when transmission errors occur.
2Quantity of substance
If predictive coding is used to minimize code amount, then code amount is reduced, but error resilience deteriorates
Solution Approach 1:
The code is segmented into two vectors with different coding strategies. The first code vector uses predictive coding to minimize code amount, while the second code vector uses non-predictive coding to provide error resilience. This segmentation allows the system to achieve both goals simultaneously.
Solution Approach 2:
The coding system uses a composite approach combining two different coding methods (predictive and non-predictive) in a single code structure. This composite coding strategy allows the system to benefit from both the efficiency of predictive coding and the robustness of non-predictive coding against transmission errors.
3Reliability
If non-predictive coding is used for all parameters, then decoding accuracy is maintained, but code amount increases
Solution Approach 1:
Instead of applying non-predictive coding to all parameters, the system segments the parameter vector and applies non-predictive coding only to the second code vector, while the first code vector uses predictive coding. This selective segmentation maintains decoding accuracy while minimizing code amount.
Solution Approach 2:
The system applies non-predictive coding partially rather than completely. By applying it only to the second code vector and using predictive coding for the first code vector, the system achieves sufficient decoding accuracy without the excessive code amount that would result from applying non-predictive coding to all parameters.
Data Source
AI summary
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.