Audio Loudness Normalization With Section-Based Gain Limiting
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Solution Overview
Problem
The existing methods for providing audio signals to users face challenges in maintaining consistent loudness levels across different content types, leading to the 'Loudness War' where content producers intentionally mix audio more loudly, causing users to repeatedly adjust volume settings, and making it inconvenient for them to achieve optimal sound quality.
Innovation Solution
An audio signal processing method and apparatus that adjusts the output loudness level by analyzing loudness information, applying a limited loudness gain in initial sections and releasing limitations in subsequent sections, based on genre, duration, and loudness measurement values, to normalize the audio signal and provide a more stable and immersive listening experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If loudness gain is applied to normalize audio content, then loudness consistency is improved, but distortion and noise may be amplified
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the loudness gain based on the measured loudness level of the audio content. When the loudness exceeds a predetermined threshold, the gain is reduced to prevent distortion and noise amplification, while still maintaining overall loudness consistency across different contents.
2Ease of operation
If loudness normalization is applied to all contents, then user convenience is improved, but sound quality may deteriorate due to excessive gain application
Solution Approach 1:
The patent changes the gain parameter dynamically based on the audio content's loudness characteristics. By measuring the actual loudness level and applying appropriate gain adjustment, it achieves loudness normalization that maintains sound quality while improving user convenience.
3Object-generated harmful factors
If loudness gain is limited in initial section, then distortion is prevented, but loudness normalization effectiveness is reduced
Solution Approach 1:
The patent segments the audio content into an initial section and a subsequent section, applying different gain control strategies to each. In the initial section, gain is limited to prevent distortion, while in the subsequent section, full normalization is applied to achieve overall loudness consistency.
Solution Approach 2:
The patent performs preliminary action by analyzing the loudness characteristics of the initial section before applying full normalization to the subsequent sections. This preliminary analysis allows the system to determine appropriate gain levels that prevent distortion while maintaining normalization effectiveness.
Data Source
AI summary
The audio signal processing apparatus includes a processor configured to adjust an output loudness level of an input content. The processor is configured to obtain a loudness information analyzed from the input content, obtain a loudness gain applied to the input content based on the loudness information and a target loudness level, and adjust the output loudness level of the input content based on the loudness gain. In this case, in a first section among an entire section in which the input content is reproduced, the loudness gain is limited based on a first gain allowable range, and in a second section following the first section, the limitation on the loudness gain is released.