Multichannel Signal Decoding with Frame-to-Frame Phase Control
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Solution Overview
Problem
Existing multi-channel signal decoding methods face challenges in reducing data transmission requirements while maintaining sound quality, particularly due to rapid changes in phase parameters that lead to noise and degradation in stereo signal playback.
Innovation Solution
The proposed solution involves an apparatus and method that selectively encodes and modifies phase parameters, such as Inter-channel Phase Difference (IPD) and Overall Phase Difference (OPD), to reduce bit allocation and noise, using techniques like quantization and parameter estimation, and modifying phase parameters to control changes across frames, thereby improving sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase parameters are encoded with high precision to maintain sound quality, then sound quality is improved, but data transmission requirements increase
Solution Approach 1:
The patent changes the representation parameters of phase information by converting absolute phase values into relative phase differences between adjacent frames. This parameter transformation reduces the dynamic range and variability of encoded data, allowing for more efficient quantization and compression while preserving perceptually relevant audio information.
Solution Approach 2:
The patent applies preliminary processing to phase parameters by predicting expected phase values based on previous frames and encoding only the deviation from prediction. This preliminary action reduces the amount of information that needs to be transmitted, as the decoder can reconstruct most phase information from historical data without receiving it explicitly.
2Reliability
If phase parameters are modified to control changes across frames, then noise is reduced and sound quality is improved, but processing complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the encoder monitors phase parameter changes across frames and applies modification only when necessary to prevent noise. The system uses the decoded output from previous frames as feedback to adjust current frame encoding, creating a closed-loop control that reduces noise while maintaining efficiency.
Solution Approach 2:
The patent introduces dynamic adaptation in phase parameter encoding by adjusting encoding strategies based on the actual phase variation observed in different frames. The system dynamically switches between different encoding modes or quantization levels depending on the complexity of phase changes, optimizing the balance between quality and complexity for each frame.
Data Source
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AI summary
Disclosed is an apparatus for encoding/decoding a multichannel signal. The apparatus for encoding/decoding a multichannel signal processes phase parameters for phase information among a plurality of channels constituting the multichannel signal in consideration of the characteristics of the multichannel signal. The apparatus generates an encoded bit stream for the multichannel signal using the processed phase parameters and the mono signal extracted from the multichannel signal.