Space Warping for Higher-Order Ambisonics Sound Object Positioning
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Solution Overview
Problem
Current techniques for manipulating the spatial arrangement of audio scenes captured with Higher-Order Ambisonics (HOA) are limited, as they require sophisticated decomposition or only allow for rotation, mirroring, and emphasis of directions, failing to change the relative positions of sound objects within the scene effectively.
Innovation Solution
The method employs space warping in the HOA domain, allowing for flexible modification of sound field information through linear matrix multiplication, enabling changes in sound object positions without scene analysis or decomposition, and is applicable to both 2D and 3D sound fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If scene decomposition is performed to manipulate sound object positions, then position manipulation capability is improved, but device complexity and error probability increase
Solution Approach 1:
The invention extracts the position manipulation function from the complex scene decomposition process by applying space warping directly to the HOA representation. This allows position manipulation without needing to separate and analyze individual sound objects, thereby reducing complexity while maintaining the desired adaptability.
Solution Approach 2:
The invention changes the spatial parameters of the HOA representation through warping functions that transform the spatial coordinates. By modifying the spatial parameters directly in the HOA domain rather than through scene decomposition, the system achieves position manipulation with reduced complexity and error probability.
2Device complexity
If linear transformation of HOA vectors is used, then device complexity is reduced, but position manipulation capability is limited to rotation and mirroring only
Solution Approach 1:
The invention introduces dynamic space warping functions that can adaptively transform spatial coordinates beyond fixed rotation and mirroring operations. This allows the system to achieve versatile position manipulation while maintaining the computational efficiency of linear transformations through matrix multiplication.
Solution Approach 2:
The invention extends the transformation capability by applying warping in the spatial domain of the HOA representation, effectively adding another dimension of manipulation freedom. This allows position changes that go beyond simple rotation and mirroring while still using efficient linear algebra operations.
3Adaptability or versatility
If space warping is applied to change relative positions, then position manipulation flexibility is improved, but computational complexity increases
Solution Approach 1:
The invention replaces complex mechanical or algorithmic scene analysis systems with a mathematical warping function applied directly to the HOA coefficients. This substitution uses efficient matrix multiplication operations instead of computationally intensive scene decomposition and reconstruction processes.
Solution Approach 2:
The invention performs the spatial transformation through pre-computed warping matrices that can be applied directly to the HOA representation. By preparing the transformation matrices in advance and applying them through efficient matrix multiplication, the computational complexity is reduced compared to real-time scene analysis and manipulation.
Data Source
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AI summary
Higher-order Ambisonics HOA is a representation of spatial sound fields that facilitates capturing, manipulating, recording, transmission and playback of complex audio scenes with superior spatial resolution, both in 2D and 3D. The sound field is approximated at and around a reference point in space by a Fourier-Bessel series. The invention uses space warping (12, 13, 14; 16) for modifying the spatial content and/or the reproduction of sound-field information that has been captured or produced as a higher-order Ambisonics representation. Different warping characteristics are feasible for 2D and 3D sound fields. The warping is performed in space domain without performing scene analysis or decomposition. Input HOA coefficients with a given order are decoded to the weights or input signals of regularly positioned (virtual) loudspeakers.