Mid-Side Audio Processing for Computational Efficiency

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Solution Overview

Problem

Traditional hearing aid processors face computational strain with sound augmentation, particularly in stereo audio devices, due to the need to process both left and right channels independently, which is inefficient and can lead to reduced sound quality.

Innovation Solution

The method involves encoding left and right audio signals as mid and side channels, processing only one channel fully with dynamic range compression, and recombining them to produce a dynamic range compressed representation, reducing computational workload while maintaining sound quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If both left and right audio channels are fully processed with dynamic range compression, then sound quality is improved, but computational workload increases significantly

Engineering Contradiction:
Improvesound qualityVSAvoidcomputational efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The audio processing is segmented into two distinct pathways: a first pathway that applies full dynamic range compression with spectral decomposition and sub-band processing, and a second pathway that applies simplified dynamic range compression without spectral decomposition. This segmentation allows the system to process different audio components with different levels of computational intensity, thereby improving overall computational efficiency while maintaining sound quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing qualities are applied to different audio channels based on their specific requirements. The first audio channel (mid channel) receives full spectral decomposition and sub-band dynamic range compression, while the second audio channel (side channel) receives simplified full-band dynamic range compression. This local quality approach ensures that computational resources are allocated efficiently to where they are most needed.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If sound augmentation is performed on stereo audio devices with limited processing capabilities, then sound quality can be maintained, but computational resources are strained

Engineering Contradiction:
Improvesound qualityVSAvoidprocessing capability requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of applying full spectral decomposition and sub-band processing to both audio channels, the system applies this intensive processing only to the first channel (mid channel), while applying simplified processing to the second channel (side channel). This partial action approach maintains sound quality for the most important audio components while reducing the overall computational burden on devices with limited processing capabilities.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If centralized stereo processing is implemented on a single decoder, then sophisticated sound processing techniques can be applied, but processing power requirements increase

Engineering Contradiction:
Improvesound processing capabilityVSAvoidprocessing power
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The centralized stereo processing is segmented into two pathways with different computational requirements. The first pathway handles spectral decomposition and sub-band processing for sophisticated sound processing, while the second pathway handles simplified full-band processing. This segmentation enables sophisticated sound processing techniques to be applied where needed while reducing overall processing power requirements through the simplified second pathway.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3599775B1Systems and methods for processing an audio signal for replay on stereo and multi-channel audio devices
Publication Date: 2021.04.07 MIMI HEARING TECHNOLOGIES GMBH
  • EP3599775B1 patent drawingFigure 1
  • EP3599775B1 patent drawingFigure 2
  • EP3599775B1 patent drawingFigure 3

AI summary

Disclosed are systems and methods for processing an audio signal on a stereo audio device. Left and right audio signals are encoded as mid and side channel signals by taking the sum and difference of the left and right audio signals, respectively. The side channel is outputted to a first signal pathway that features a dynamic range compressor. The mid channel is outputted to a second signal pathway which is then spectrally decomposed into a plurality of sub-band signals using one or more bandpass filters. Each sub-band signal is then provided to a dynamic range compressor, compressed and outputted to a gain stage. Subsequently, each compressed sub-band signal is outputted from the gain stage and recombined. The outputs of the first and second signal pathways are then recombined and decoded in order to produce left and right audio signals. The left and right audio signals are then outputted.