Stereo Residual Encoding by Sub-Band Energy for Spatial Stability
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Solution Overview
Problem
Existing stereo signal encoding methods suffer from high-frequency distortion and poor spatial sense and sound-image stability, particularly at low coding rates, due to insufficient encoding of high-frequency information in the downmixed signal.
Innovation Solution
A method for determining a residual signal encoding parameter based on downmixed and residual signal energies of sub-bands, deciding whether to encode residual signals, thereby optimizing encoding to reduce high-frequency distortion while maintaining spatial sense and sound-image stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If residual signals of sub-bands are encoded at low coding rates, then high-frequency information is preserved improving spatial sense and sound-image stability, but encoding bit allocation becomes insufficient causing high-frequency distortion
Solution Approach 1:
The patent dynamically changes the encoding parameter (residual signal encoding flag) based on the coding rate and sub-band characteristics. At low coding rates, the system selectively encodes residual signals only in sub-bands where they provide the most benefit, changing the encoding behavior from uniform to adaptive based on frequency characteristics
Solution Approach 2:
The patent applies different encoding strategies to different sub-bands based on their frequency characteristics. High-frequency sub-bands receive residual signal encoding when beneficial, while low-frequency sub-bands use standard downmixed signal encoding, creating local quality optimization across the frequency spectrum
2Productivity
If downmixed signal encoding is prioritized at low coding rates, then encoding efficiency is improved, but high-frequency information is lost reducing spatial sense and sound-image stability
Solution Approach 1:
Instead of fully encoding all residual signals (excessive action) or encoding none (insufficient action), the patent applies partial encoding by selectively enabling residual signal encoding only in specific sub-bands where it provides the most benefit, achieving optimal balance between efficiency and quality
Solution Approach 2:
The system changes the encoding parameter (residual signal encoding flag) based on coding rate conditions, transitioning from a fixed encoding strategy to a dynamic one that adapts to available bit budget while preserving critical high-frequency information
Data Source
AI summary
A stereo signal encoding method includes: obtaining a residual signal encoding parameter of a current frame of a stereo signal based on downmixed signal energy and residual signal energy of each of M sub-bands of the current frame, where the residual signal encoding parameter indicates whether to encode residual signals of the M sub-bands; determining whether to encode the residual signals based on the residual signal encoding parameter; and encoding the residual signals when it is determined that the residual signals need to be encoded.