Hybrid Audio Filter Frequency Warping Timbre Preservation
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Solution Overview
Problem
Existing audio decorrelation methods introduce unintended timbral changes and artifacts, such as modifying the perceived location of audio sources and timbre, when reducing correlation between audio signals.
Innovation Solution
A method involving the generation of a decorrelation filter with frequency-dependent warping, mixed with a carrier filter to create a hybrid filter, which processes audio signals, reducing unwanted distortions and preserving timbre by applying frequency-dependent weighting to the phase of the decorrelation filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random phase filtering is used to reduce correlation between audio signals, then the spatial imagery is modified (decorrelation achieved), but timbral changes and unintended artifacts are introduced
Solution Approach 1:
The patent changes the parameter of phase randomization from uniform across all frequencies to frequency-dependent. By applying different amounts of phase randomization at different frequencies (more at low frequencies, less at high frequencies), the system achieves effective decorrelation while preserving timbral characteristics that would otherwise be distorted by uniform phase randomization.
Solution Approach 2:
The patent applies different processing characteristics to different frequency regions. The frequency-dependent warping function creates local variations in phase randomization intensity, allowing aggressive decorrelation where needed (low frequencies) while maintaining fidelity where it matters for timbre (high frequencies).
2Object-generated harmful factors
If frequency-dependent warping is applied to the decorrelation filter, then timbral modifications are minimized, but the filter design and processing complexity increases
Solution Approach 1:
The patent introduces a frequency-dependent warping function as an intermediary element between the random phase generation and the final filter implementation. This warping function acts as a controller that shapes the phase randomization characteristics without requiring complete redesign of the underlying decorrelation filter structure, thus managing complexity while achieving timbral preservation.
3Productivity
If the decorrelation filter is mixed with carrier filter to create hybrid filter, then processor and memory load is reduced, but the filtering operations become more complex
Solution Approach 1:
The patent merges the decorrelation filter and carrier filter into a single hybrid filter structure. By combining these two filtering operations into one unified filter, the system reduces the number of separate filtering passes required, thereby decreasing processor and memory load while the internal structure of the hybrid filter manages the complexity of performing both decorrelation and carrier functions simultaneously.
Data Source
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AI summary
Various embodiments relate to a system and method for decorrelating an audio signal with a hybrid filter. The hybrid filter is generated by first generating a decorrelation filter. A frequency-dependent warping is applied to the decorrelation filter. The warped decorrelation filter is then mixed with a carrier filter to generate the hybrid filter. The carrier filter may include filters for spatial processing of an audio signal, filters for upmixing an audio signal, and/or filters for downmixing an audio signal.