Multisignal Audio Coding with Signal Whitening for Lower Data Transmission

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Solution Overview

Problem

Existing audio encoding technologies struggle to efficiently encode multichannel audio signals, particularly in immersive 3D audio formats, due to limitations in joint channel coding techniques that fail to consider spatial and perceptual relations between channels, leading to increased data transmission requirements and reduced perceptual audio quality.

Innovation Solution

A multisignal encoder and decoder system that preprocesses audio signals to make them perceptually whitened and energy normalized, followed by adaptive joint signal processing to enhance efficiency, using techniques like M/S transform decisions and broadband energy normalization, and entropy encoding to reduce data transmission while maintaining quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If joint stereo coding is performed on non-whitened signals, then the coding process is simpler, but the coding efficiency and perceptual audio quality are reduced

Engineering Contradiction:

Improvecoding process simplicityVSAvoidcoding efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies preliminary whitening processing to the audio signals before joint stereo coding. This preprocessing step transforms the signals to have a flatter spectral distribution, which improves the effectiveness of subsequent joint coding operations and enhances perceptual audio quality without significantly increasing overall system complexity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the spectral parameters of the audio signals through whitening transformation. This parameter change modifies the signal characteristics to be more suitable for joint stereo coding, improving coding efficiency by better exploiting inter-channel correlations in the whitened domain

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If joint stereo coding is performed on non-whitened signals, then the system complexity is lower, but the exploitation of inter-channel dependencies is insufficient

Engineering Contradiction:

Improvesystem complexityVSAvoidinter-channel dependency exploitation

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

Whitening is applied as a preliminary step to prepare the signals for more effective joint coding. This preprocessing enhances the inter-channel dependencies in the transformed domain, allowing the joint stereo coder to better exploit correlations between channels and reduce information loss

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If more bits are allocated for prediction coefficients in each band, then the audio quality is improved, but the data transmission requirements increase

Engineering Contradiction:

Improveaudio qualityVSAvoiddata transmission

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent changes the spectral distribution parameters through whitening, which concentrates the signal energy more uniformly across frequency bands. This allows for more efficient bit allocation where fewer bits are needed per band to achieve the same perceptual quality, reducing overall data transmission requirements

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional approach of increasing bit allocation with a signal transformation approach. By applying whitening transformation, the system achieves better coding efficiency and audio quality without relying on increased data transmission, substituting a mechanical increase in data quantity with a sophisticated signal processing approach

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12367883B2Multisignal audio coding using signal whitening as processing

Publication Date: 2025.07.22 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

A multisignal encoder for encoding at least three audio signals, including: a signal preprocessor for individually preprocessing each audio signal to obtain at least three preprocessed audio signals, wherein the preprocessing is performed so that a preprocessed audio signal is whitened with respect to the signal before preprocessing; an adaptive joint signal processor for performing a processing of the at least three preprocessed audio signals to obtain at least three jointly processed signals or at least two jointly processed signals and an unprocessed signal; a signal encoder for encoding each signal to obtain one or more encoded signals; and an output interface for transmitting or storing an encoded multisignal audio signal including the one or more encoded signals, side information relating to the preprocessing and side information relating to the processing.