Multi-Channel Signal Encoding for Low-Correlation Reverberation

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Solution Overview

Problem

Existing stereo audio encoding methods, particularly parametric stereo encoding, result in poor auditory effects when reverberation processing is performed on channel signals with low correlation, leading to distorted output.

Innovation Solution

A multi-channel signal encoding method that determines a target reverberation gain parameter based on the correlation between channel signals and a downmixed signal, adjusting the initial gain parameter using an attenuation factor to improve the quality of reverberation processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reverberation processing is performed on channel signals with low correlation using prior art methods, then processing is completed, but auditory effects deteriorate

Engineering Contradiction:
Improveauditory effect qualityVSAvoiddistortion in output
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the reverberation gain parameter based on the correlation between channel signals. When correlation is low, the gain parameter is attenuated to prevent excessive reverberation effects that cause distortion. This dynamic parameter adjustment resolves the contradiction by adapting the processing intensity to the signal characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic adjustment of reverberation gain parameters according to the correlation between channel signals. The system continuously monitors signal correlation and modifies processing parameters in real-time, transitioning from static to dynamic processing to maintain optimal auditory quality across varying signal conditions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If reverberation gain parameter is adjusted based on correlation with downmixed signal, then auditory effects improve, but calculation complexity increases

Engineering Contradiction:
Improveauditory effect qualityVSAvoidcalculation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the downmixed signal as an intermediary reference to calculate correlation with individual channel signals. This intermediary approach simplifies the overall calculation by providing a common reference point, making the correlation computation more efficient while still capturing the essential relationships between channels.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention calculates correlation parameters between channel signals and the downmixed signal to dynamically adjust reverberation gain. By focusing on these specific parameter relationships rather than full signal processing, the method achieves improved auditory quality with manageable computational complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4641564A1Multi-channel signal encoding method, multi-channel signal decoding method, encoder, and decoder
Publication Date: 2025.10.29 HUAWEI TECH CO LTD
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AI summary

A multi-channel signal encoding method, a multi-channel signal decoding method, an encoder, and a decoder are provided. The encoding method includes: determining a downmixed signal of a first channel signal and a second channel signal in a multi-channel signal, an initial reverberation gain parameter of the first channel signal and the second channel signal; determining a target reverberation gain parameter of the first channel signal and the second channel signal based on a correlation between the first channel signal and the downmixed signal, a correlation between the second channel signal and the downmixed signal, and the initial reverberation gain parameter; and quantizing the first channel signal and the second channel signal based on the downmixed signal and the target reverberation gain parameter, and writing a quantized first channel signal and a quantized second channel signal into a bitstream. Quality of a channel signal obtained after reverberation processing can be improved according to the encoding method, the decoding method, the encoder, and the decoder.