Audio Post-Processing State Update via Resampling

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Solution Overview

Problem

Existing audio frequency signal processing technologies face challenges in maintaining post-processing quality when the sampling frequency changes between frames, leading to audible artifacts and suboptimal noise reduction.

Innovation Solution

A method that involves resampling the past decoded signal at the current frame's sampling frequency using interpolation, allowing the post-processing memory to adapt and maintain quality during frequency transitions, while minimizing computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the sampling frequency is changed between frames to adapt to different audio conditions, then the adaptability of the audio processing system is improved, but artifacts and degradation of post-processing quality occur

Engineering Contradiction:

Improvesampling frequency adaptabilityVSAvoidaudible artifacts

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by resampling the past decoded signal at the current frame's sampling frequency before it is needed for post-processing. This preparatory resampling ensures that when the current frame is processed, the memory already contains signals at the correct sampling frequency, preventing artifacts and maintaining quality during frequency transitions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary resampling operation with interpolation to bridge the gap between different sampling frequencies. The resampled past decoded signal acts as an intermediary that allows seamless transition between different sampling frequencies while maintaining signal integrity and avoiding audible artifacts.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the past decoded signal is resampled at the current frame's sampling frequency using interpolation, then post-processing quality is maintained during frequency transitions, but computational complexity increases

Engineering Contradiction:

Improvepost-processing qualityVSAvoidcomputational complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by performing interpolation only on the necessary portion of the past decoded signal that will be used for post-processing. Rather than resampling the entire signal history, only the relevant past samples are resampled at the current frame's sampling frequency, reducing unnecessary computational complexity while maintaining quality.

Inventive Principle:

Principle #16Partial or excessive action

3Device complexity

If the sampling frequency remains fixed for all frames, then computational complexity is reduced and processing is simplified, but the system cannot adapt to varying audio conditions and produces artifacts during frequency transitions

Engineering Contradiction:

Improveprocessing simplicityVSAvoidsampling frequency adaptability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the sampling frequency adaptive rather than fixed. The system dynamically adjusts the sampling frequency for each frame based on the current audio conditions, allowing the processing parameters to change flexibly in response to varying signal characteristics while maintaining overall system simplicity through the use of resampling and interpolation.

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach improves post-processing quality during sampling frequency changes, reducing artifacts and optimizing memory usage, resulting in enhanced audio signal processing without significant increases in complexity.

Implementation Method 1

resampling the past decoded signal obtained, at the sampling frequency of the current frame, by interpolation

Methodology Applied

Scientific EffectInterpolation:

Data Source

PatentUS10424313B2Update of post-processing states with variable sampling frequency according to the frame

Publication Date: 2019.09.24 ORANGE SA

AI summary

A method and apparatus are provided for updating post-processing states applied to a decoded audio signal. The method is such that, for a current decoded signal frame, sampled at a different sampling frequency from the preceding frame, it includes the following acts: obtaining a past decoded signal, stored for the preceding frame; re-sampling by interpolation of the past decoded signal obtained; using the re-sampled past decoded signal as a memory for post-processing the current frame. A decoding method is also provided, which includes updating post-processing states.