Adaptive Decorrelation Filters for Changing Auditory Scenes
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Solution Overview
Problem
Existing decorrelation filters in spatial audio processing are time-invariant, failing to adapt to variations in auditory scenes, leading to unnatural ambiance in decoded audio signals.
Innovation Solution
Adaptive control of decorrelation filter length based on transmitted performance measures, such as reverberation length and correlation measures, to match the characteristics of input signals, allowing for dynamic adjustment of decorrelation in multi-channel audio decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If time-invariant decorrelation filters are used, then device complexity is reduced, but adaptability to variations in auditory scenes deteriorates
Solution Approach 1:
The patent implements dynamic adaptation of decorrelation filter parameters by calculating time-varying decorrelation measures from the audio signal and using these measures to adjust filter characteristics. This allows the filter to adapt to changing auditory scenes while maintaining manageable complexity through efficient algorithms for measuring and adapting to signal correlations.
Solution Approach 2:
The patent changes the parameters of the decorrelation filter based on measured decorrelation properties of the input signal. By dynamically adjusting filter parameters such as correlation thresholds and adaptation rates according to the actual signal characteristics, the system achieves adaptability without requiring a completely complex reconfiguration of the filter structure.
2Adaptability or versatility
If adaptive control of decorrelation filter length is implemented, then adaptability to different audio types is improved, but device complexity increases
Solution Approach 1:
The patent adapts the decorrelation filter length by dynamically changing this parameter based on the measured decorrelation measure of the input signal. The system calculates a decorrelation measure from the audio signal and uses this measure to select or adjust the filter length, achieving adaptability to different audio types through parameter adjustment rather than structural complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the decorrelation measure calculated from the input signal is fed back to control the decorrelation filter parameters. This closed-loop approach allows the system to automatically adapt to different audio types by continuously measuring signal characteristics and adjusting filter length accordingly, managing complexity through efficient feedback processing.
3Manufacturing precision
If decorrelation filter parameters are dynamically adjusted, then perceived audio quality is improved, but processing time increases
Solution Approach 1:
The patent dynamically adjusts decorrelation filter parameters including length and threshold values based on the measured decorrelation measure of the input signal. By changing these parameters to match the actual signal characteristics, the system improves audio quality precision while managing processing time through efficient parameter adjustment algorithms that avoid excessive computation.
Solution Approach 2:
The patent implements dynamic parameter adjustment of the decorrelation filter based on real-time signal analysis. The system continuously adapts filter characteristics to match the auditory scene variations, improving perceived audio quality through dynamic optimization while maintaining acceptable processing speeds through efficient adaptive algorithms.
Data Source
AI summary
An audio signal processing method and apparatus for adaptively adjusting a decorrelator. The method comprises obtaining a control parameter and calculating mean and variation of the control parameter. Ratio of the variation and mean of the control parameter is calculated, and a decorrelation parameter is calculated based on the said ratio. The decorrelation parameter is then provided to a decorrelator.