Forced Gap Audio Playback for Background Noise Estimation

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Solution Overview

Problem

Current noise compensation methods in audio playback systems face challenges in accurately estimating background noise levels due to the 'echo problem', where microphones capture both playback content and noise, leading to suboptimal noise compensation, especially in low-cost devices with weak or non-existent echo cancellation capabilities.

Innovation Solution

The method involves inserting forced gaps into the audio playback signal to generate a modified signal that allows a pervasive listener to monitor non-playback sound, enabling improved noise estimation and compensation by distinguishing between playback and background noise without relying on echo cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If forced gaps are inserted into the audio playback signal to enable monitoring of non-playback sound, then noise estimation accuracy is improved, but audio playback continuity is disrupted

Engineering Contradiction:
Improvenoise estimation accuracyVSAvoidaudio playback continuity
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The system inserts forced gaps periodically into the audio playback signal at predetermined time intervals. These periodic interruptions allow the microphone to capture non-playback sound (ambient noise) without continuous playback interference. The periodic nature balances the need for noise measurement with maintaining overall playback continuity, as gaps are inserted only at specific intervals rather than continuously.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The audio playback signal is segmented by inserting forced gaps that divide the continuous playback into discrete segments. This segmentation allows the system to separate playback content from ambient noise during gap periods, enabling accurate noise estimation. The segmented approach permits selective monitoring during gap intervals while preserving playback during non-gap intervals.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple forced gaps are inserted across different frequency bands to estimate full spectrum noise, then noise estimation coverage is improved, but playback signal modification complexity increases

Engineering Contradiction:
Improvenoise estimation coverageVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The frequency spectrum is segmented into multiple bands, and forced gaps are inserted selectively into specific frequency bands rather than uniformly across all bands. This segmented approach allows the system to estimate noise across the full spectrum by combining measurements from multiple bands, while reducing overall complexity compared to modifying every frequency band simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different frequency bands are treated with different gap insertion strategies based on local requirements. The system applies forced gaps selectively to specific frequency bands where noise estimation is most needed, rather than applying uniform gap insertion across all bands. This local quality approach optimizes noise estimation coverage while minimizing unnecessary signal modification complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3830823B1Forced gap insertion for pervasive listening
Publication Date: 2022.04.27 DOLBY LABORATORIES LICENSING CORP
  • EP3830823B1 patent drawingFigure 1~2
  • EP3830823B1 patent drawingFigure 3~4
  • EP3830823B1 patent drawingFigure 5~7

AI summary

A pervasive listening method including steps of inserting at least one forced gap in a playback signal (thus generating a modified playback signal), and during playback of the modified playback signal, monitoring non-playback content (e.g., including by generating an estimate of background noise) in a playback environment using output of a microphone in the playback environment. Optionally, the method includes generation of the playback signal, including by processing of (e.g., performing noise compensation on) an input signal using a result (e.g., a background noise estimate) of the monitoring of non-playback content. Other aspects are systems configured to perform any embodiment of the pervasive listening method.