Multichannel Audio Signal Encoding with Iterative Weighted Difference Coding
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Solution Overview
Problem
Conventional multichannel audio signal coding methods achieve low compression efficiencies due to limitations in determining optimal pairs for weighted difference coding, leading to suboptimal compression rates for certain channel pairs.
Innovation Solution
A multistage coding process is employed to determine the best channel to use as a reference for weighted difference coding, with at least one channel using a weighting factor of 0, allowing for iterative compression of weighted difference signals, and the weighting factors are coded and outputted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional weighted difference coding is used with fixed channel pairing, then the coding process is simple, but the compression efficiency is low due to suboptimal channel pair selection
Solution Approach 1:
The patent applies dynamics by making the channel pairing and weighting factors adjustable rather than fixed. The system dynamically determines optimal channel pairs and weighting factors based on signal characteristics, allowing the coding process to adapt to different audio scenarios and achieve higher compression efficiency.
Solution Approach 2:
The patent changes parameters by introducing variable weighting factors that can be adjusted for different channel pairs. Instead of using fixed weights, the system optimizes weighting factors based on the correlation between channels, enabling flexible adaptation to various signal conditions and improving overall compression performance.
2Productivity
If all channel signals are subjected to weighted difference coding, then compression rate improves, but some channels may not have suitable reference signals leading to suboptimal results
Solution Approach 1:
The patent applies local quality by treating each channel differently based on its specific characteristics and correlation with other channels. Not all channels are treated uniformly; instead, the system identifies which channels are suitable for weighted difference coding and which should be coded independently, optimizing the coding strategy for each local channel situation.
Solution Approach 2:
The patent segments the multichannel coding process into separate stages: first determining optimal channel pairs and weighting factors, then applying weighted difference coding to suitable channels, and finally coding remaining channels independently. This segmentation allows flexible application of compression techniques only where beneficial.
3Productivity
If iterative multistage coding is implemented to determine optimal reference channels, then compression efficiency improves, but the coding process becomes more complex
Solution Approach 1:
The patent applies preliminary action by performing channel correlation analysis and weighting factor determination before the actual coding process. The system pre-determines optimal channel pairs and weights based on signal statistics, which then guides the coding process. This preliminary preparation enables efficient iterative coding without excessive computational complexity during the main coding operation.
Data Source
AI summary
An object of the present invention is to efficiently perform weighted difference coding of two or more signals. Determination is made as to which of independent coding and weighted difference coding is to be used for each channel so that the total energy of the channel signals and weighted difference signals is minimized. A weighted difference signal is generated on the basis of the determination and a reference signal (parent) and a weight is generated as auxiliary codes, the difference signal is treated as an input channel signal, and the process of coding determination and difference signal and auxiliary code generation is repeated. The difference signal generated at the last iteration of the process and a signal to be coded by independent coding are compressive coded and the auxiliary codes generated at the iterations of the process are coded and outputted.