DRC Parameter Estimation for Audio Dynamic Range Inversion
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Solution Overview
Problem
Current dynamic range control (DRC) technologies struggle to accurately reproduce the behavior of unknown DRC models and reverse DRC effects, particularly in scenarios where the original model parameters are not accessible, leading to issues like over-compression and difficulty in restoring the original dynamic range of audio signals.
Innovation Solution
A method is proposed to determine and estimate DRC parameters for a known DRC model by feeding an audio signal through a second DRC model, selecting pairs of samples, and adjusting parameters to minimize distance functions, allowing for the approximation of unknown DRC models and reversing dynamic range compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dynamic range control is applied to reduce distortion and maximize playback level, then audio quality is improved, but the original dynamic range cannot be restored when model parameters are inaccessible
Solution Approach 1:
The patent creates a replica of the unknown DRC model by feeding audio signals through both the unknown model and a known DRC model, then adjusting the known model's parameters to minimize the distance between their outputs. This copying approach allows the system to reproduce the behavior of unknown DRC models without direct access to their parameters, enabling subsequent reversal of DRC effects while maintaining audio quality improvements.
2Adaptability or versatility
If multiple compressors are applied to audio content, then dynamic range is controlled, but playback quality degrades due to over-compression and artifacts
Solution Approach 1:
The patent applies inversion by reversing the DRC process through an inverse function. After determining the DRC model parameters by minimizing distance between known and unknown model outputs, the system applies the inverse function to restore the original audio signal from the compressed signal, thereby removing over-compression artifacts and restoring playback quality while maintaining the benefits of dynamic range control.
3Adaptability or versatility
If DRC parameters are determined without access to metadata, then system flexibility is improved, but parameter determination becomes more difficult
Solution Approach 1:
The patent employs feedback by iteratively adjusting the parameters of the known DRC model and evaluating the distance between its output and the output of the unknown DRC model. This feedback loop continues until the distance is minimized, allowing the system to automatically determine accurate DRC parameters without requiring access to metadata, thereby achieving both flexibility and accuracy in parameter determination.
Data Source
AI summary
The present disclosure relates to a method of determining parameters for use by a first dynamic range control, DRC, model. The method comprises feeding a first audio signal to a second DRC model and receiving a second audio signal from the second DRC model, the second audio signal being a dynamic range controlled version of the first audio signal, rule-based selecting one or more pairs of samples of the first audio signal and corresponding samples of the second audio signal, and determining parameters of a first set of parameters among the parameters for use by the first DRC model based on the one or more selected pairs of samples. The present disclosure further relates to a method of reversing DRC of a dynamic range controlled audio signal and to a method of declipping a clipped audio signal that has been clipped by a DRC model. The present disclosure yet further relates to corresponding apparatus and computer-readable media.