Automatic Audio Gain Control Using Equal-Loudness Analysis
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Solution Overview
Problem
Existing digital video systems and media players face instability in audio signal output due to discrepancies between different audio sources and file formats, leading to user inconvenience as they need to manually adjust volume levels frequently.
Innovation Solution
A device and method for automatically adjusting gain by converting audio signals to the frequency domain, analyzing them based on human hearing's equal-loudness level contour, calculating a gain factor, and generating an output signal to maintain consistent volume levels across different audio sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic gain adjustment is implemented using predetermined frequency bands, then gain adjustment automation is achieved, but the output audio signals do not meet users' auditory needs because predetermined frequency bands may not match input audio signals
Solution Approach 1:
The patent implements dynamic frequency band selection that adapts to different audio signal types in real-time. The system automatically identifies the type of audio signal (music, speech, etc.) and dynamically selects appropriate frequency bands for gain calculation, rather than using fixed predetermined bands. This dynamic adaptation ensures accurate frequency band matching for various input signals while maintaining automatic operation.
Solution Approach 2:
The system changes the parameters of frequency band selection based on the detected audio signal characteristics. By analyzing spectral characteristics and signal type, the system adjusts which frequency bands are used for gain calculation, transforming the static predetermined band approach into a flexible parameter-adaptive system that maintains both automation and precision.
2Stability of the object's composition
If manual volume adjustment is required for different audio sources, then audio signal stability can be maintained, but user convenience deteriorates due to frequent manual intervention
Solution Approach 1:
The system performs self-service by automatically detecting audio signal characteristics and adjusting gain parameters without user intervention. The automatic gain adjustment system monitors spectral characteristics in real-time and autonomously modifies output levels to maintain stability across different audio sources, completely eliminating the need for manual volume adjustment while preserving signal stability.
Solution Approach 2:
The system implements a feedback mechanism where the output audio signal characteristics are continuously monitored and fed back to the gain adjustment module. This closed-loop control ensures that the system automatically maintains stable output levels by detecting deviations and correcting them in real-time, providing both stability and user convenience simultaneously.
3Adaptability or versatility
If frequency domain conversion and spectral analysis are performed in real-time, then suitable frequency bands can be selected dynamically, but system complexity increases
Solution Approach 1:
The patent segments the audio signal processing into distinct functional modules: a conversion module for time-to-frequency domain transformation, an analysis module for spectral characteristic detection, and a gain calculation module for determining appropriate frequency bands. This modular segmentation manages complexity by organizing the processing pipeline into independent, manageable components that can operate efficiently in real-time.
Solution Approach 2:
The system replaces complex mechanical or manual frequency band selection mechanisms with computational signal processing. By using digital signal processing techniques for frequency domain conversion and spectral analysis, the system achieves high adaptability through software-based algorithms rather than complex hardware switching mechanisms, reducing overall system complexity while maintaining versatility.
Data Source
AI summary
A device and method are provided for automatically adjusting gain, including a conversion module for converting an audio time-domain signal to an audio frequency-domain signal, an analysis module for analyzing the audio frequency-domain signal in accordance with an equal-loudness level contour of human hearing so as to generate strength weightings and generating a signal strength in accordance with the weightings, a calculation module for calculating a gain by analysis of the audio frequency-domain signal when the signal strength falls outside a default range, and a control module for generating an audio output signal in accordance with the gain and the audio time-domain signal.