Time-Domain Stereo Encoding for Out-of-Phase Signal Energy Retention
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Solution Overview
Problem
Conventional time-domain stereo encoding technologies suffer from energy loss in primary signals, leading to decreased encoding quality, particularly when dealing with stereo audio signals that are out of phase.
Innovation Solution
A segmented time-domain encoding and decoding method that adapts channel combination schemes based on the phase relationship of left and right channel signals, employing different downmix and upmix processing for different segments to maintain signal energy and improve encoding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional time-domain stereo encoding technology is used, then encoding speed is maintained, but signal energy is lost and encoding quality decreases
Solution Approach 1:
The patent segments the stereo signal processing into different components: mid channel signal, side channel signal, and difference signal. By segmenting the encoding process and applying different handling to each component, the patent preserves signal energy that would otherwise be lost in conventional downmixing, while maintaining efficient encoding speed.
Solution Approach 2:
The patent applies different encoding strategies to different signal components based on their local characteristics. The mid channel signal is encoded with higher priority and preserved energy, while the side and difference signals are encoded with adaptive bit allocation. This local quality approach ensures that critical signal energy is maintained where needed, resolving the contradiction between speed and energy preservation.
2Device complexity
If conventional downmix processing is used, then encoding complexity is reduced, but encoding quality deteriorates due to energy loss
Solution Approach 1:
The patent divides the stereo signal into segmented components (mid, side, difference) that can be processed independently with different complexity levels. This segmentation allows the system to maintain lower overall encoding complexity while improving reliability by preserving energy in critical signal components through targeted processing strategies.
Solution Approach 2:
The patent changes the processing parameters by introducing separate encoding paths for different signal components with different bit allocation priorities. This parameter change enables the system to maintain computational efficiency while significantly improving encoding quality by preventing energy loss in the primary mid channel signal.
3Adaptability or versatility
If channel combination schemes are switched between frames, then adaptability to different signal types is improved, but signal continuity and quality deteriorate due to abrupt transitions
Solution Approach 1:
The patent implements dynamic channel combination scheme selection that adapts to the current frame's signal characteristics while maintaining continuity with previous frames. The system dynamically adjusts the encoding approach based on signal type (in-phase, out-of-phase, correlated, uncorrelated) but does so in a controlled manner that preserves signal continuity and avoids abrupt quality degradation.
Solution Approach 2:
The patent ensures continuous and smooth transitions between different channel combination schemes by maintaining consistent processing principles across frame boundaries. The useful action of signal encoding continues without interruption or abrupt changes, ensuring that adaptability to different signal types does not compromise signal continuity or quality.
Data Source
AI summary
An audio encoding and decoding method and a related apparatus are provided. The audio encoding method includes: determining a channel combination scheme for a current frame; when the channel combination scheme for the current frame is different from a channel combination scheme for a previous frame, performing segmented time-domain downmix processing on left and right channel signals in the current frame based on the channel combination scheme for the current frame and the channel combination scheme for the previous frame, to obtain a primary channel signal and a secondary channel signal in the current frame; and encoding the obtained primary channel signal and secondary channel signal in the current frame.