Adaptive Stereo Encoding for Stable Sound Image Positioning

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Solution Overview

Problem

Existing time domain stereo encoding methods fail to consider the signal type of stereo audio signals, leading to unstable sound images and a drift phenomenon in synthesized stereo audio, necessitating improved encoding quality.

Innovation Solution

A stereo encoding method that selects different encoding modes based on the signal type of the audio signal, involving time domain preprocessing, delay alignment, and channel combination solutions, including near in-phase and out-of-phase signal processing, to determine a quantized channel combination ratio factor and encoding index for optimal encoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a unified stereo encoding method is used without considering signal type, then the encoding process is simple, but the sound image becomes unstable and drift phenomenon occurs

Engineering Contradiction:
Improveencoding process simplicityVSAvoidsound image stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the encoding method adaptive rather than fixed. The encoder dynamically selects between different channel combination solutions (in-phase or out-of-phase) based on the signal type detected in each frame, allowing the encoding process to adapt to varying audio characteristics while maintaining sound image stability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the encoding parameters based on signal type. By detecting whether the signal is in-phase or out-of-phase and adjusting the channel combination ratio accordingly, the system optimizes encoding quality for different signal characteristics while preventing sound image drift

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If different encoding modes are selected based on signal type, then encoding quality is improved and sound image stability is enhanced, but the encoding process becomes more complex

Engineering Contradiction:
Improveencoding qualityVSAvoidencoding process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing signal type detection and channel combination solution determination before the actual encoding process. This preliminary classification allows the system to select the appropriate encoding mode in advance, ensuring high encoding quality while managing complexity through structured preprocessing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the encoding process into distinct stages: signal type detection, channel combination solution determination, and mode-specific encoding. This segmentation allows each stage to be optimized independently, improving overall encoding quality while making the complex process more manageable and systematic

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4712073A1Stereo encoding method and stereo encoder
Publication Date: 2026.03.18 HUAWEI TECH CO LTD
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  • EP4712073A1 patent drawingFigure 2
  • EP4712073A1 patent drawingFigure 3~4

AI summary

A stereo encoding method and a stereo encoder are provided. When stereo encoding is performed, a channel combination encoding solution of a current frame is first determined, and then a quantized channel combination ratio factor of the current frame and an encoding index of the quantized channel combination ratio factor are obtained based on the determined channel combination encoding solution, so that an obtained primary channel signal and secondary channel signal of the current frame meet a characteristic of the current frame, it is ensured that a sound image of a synthesized stereo audio signal obtained after encoding is stable, drift phenomena are reduced, and encoding quality is improved.