Hierarchical Audio Dynamics Control for Spatial Image Preservation
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Solution Overview
Problem
Existing audio dynamics processing technologies face challenges in maintaining the spatial image and spectral balance when applying dynamic range control, particularly with high compression ratios, leading to artifacts like cross-modulation and pumping, which alter the perceived sound unnatural and distort the spatial image.
Innovation Solution
A hierarchical control path is introduced, where information is derived from multiple nodes at different levels of a hierarchy, allowing for spatial and temporal remote application of dynamics modification parameters, constraining signal modifications to maintain relative levels and spectral balance across channels and frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dynamic range control with high compression ratio is applied to multichannel audio signal, then signal level is brought closer to threshold, but cross-channel pumping artifacts occur and spatial image is distorted
Solution Approach 1:
The patent segments the control of different channels by introducing hierarchical levels (channel level and band level) that allow independent processing. Each channel and frequency band has its own dynamics control that operates semi-independently, preventing cross-channel pumping while maintaining overall level control through constraints passed down the hierarchy.
Solution Approach 2:
The patent applies local quality by allowing different dynamics processing parameters to be applied to different channels and frequency bands based on their local characteristics. Each channel/band can have its own compression ratio, threshold, and release time, enabling precise local control without affecting other channels uniformly.
2Productivity
If dynamic range control is applied to multichannel audio signal, then signal level is modified, but spatial image stability deteriorates
Solution Approach 1:
The patent adds hierarchical dimensions to the control structure, introducing levels (total, channel, band) and constraint types (average, range) as new dimensions. This multi-dimensional control framework allows efficient dynamics processing while maintaining spatial image stability through coordinated control across multiple dimensions.
Solution Approach 2:
The patent implements feedback mechanisms where constraint information flows from upper hierarchical levels to lower levels, and processing results flow back upward. This feedback ensures that local processing in channels and bands remains consistent with overall spatial image requirements, maintaining stability while enabling efficient processing.
3Object-generated harmful factors
If independent channel processing is applied, then cross-channel pumping is reduced, but spatial image and virtual source positions become unstable
Solution Approach 1:
The patent structures the control system as nested hierarchical levels where channel-level controls are nested within total-level constraints, and band-level controls are nested within channel-level constraints. This nesting allows independent processing at each level while maintaining overall coherence through the hierarchical constraint structure.
Solution Approach 2:
The patent dynamically adjusts processing parameters (compression ratio, threshold, release time) at different hierarchical levels based on local signal characteristics and global constraints. Parameters change adaptively across channels and bands while maintaining spatial image stability through coordinated parameter management in the hierarchical framework.
4Stability of the object's composition
If total level measure is used for all channels, then spatial image is preserved, but cross-channel pumping occurs
Solution Approach 1:
The patent segments the single total-level control into multiple hierarchical levels (total, channel, band), allowing each segment to operate with appropriate independence. This segmentation enables spatial image preservation at the total level while preventing cross-channel pumping at the channel level through independent processing.
Data Source
AI summary
Information useful for modifying the dynamics of an audio signal is derived from one or more devices or processes operating at one or more respective nodes of each of a plurality of hierarchy levels, each hierarchical level having one or more nodes, in which the one or more devices or processes operating at each hierarchical level takes a measure of one or more characteristics of the audio signal such that the one or more devices or processes operating at each successively lower hierarchical level takes a measure of one or more characteristics of progressively smaller subdivisions of the audio signal.