Multichannel Spatial Audio Decoding With Adaptive VBAP Triangulation

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Solution Overview

Problem

Current vector base amplitude panning (VBAP) methods for spatial sound reproduction in multichannel loudspeaker systems face challenges in accurately reproducing auditory objects, particularly due to differences in horizontal and vertical panning, which result in reduced audio quality and localization issues, especially when loudspeakers are not equally distributed and when panning occurs in the vertical axis.

Innovation Solution

The proposed solution involves an adaptive triangulation scheme for VBAP that avoids triangles crossing the horizontal plane, optimizing loudspeaker setups to improve audio quality by selecting triangulation methods based on content and spatial metadata, ensuring that auditory objects are accurately positioned and rendered without intersecting planes, thereby enhancing perceptual spatial accuracy and reducing comb filtering effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional VBAP triangulation is used, then spatial sound reproduction is achieved, but audio quality and localization accuracy deteriorate when triangles cross the horizontal plane

Engineering Contradiction:
Improvelocalization accuracyVSAvoidcomb filtering effects
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by treating horizontal and vertical panning differently through adaptive triangulation. When the auditory object is near the horizontal plane, the system selects triangulation methods that avoid crossing the horizontal plane, thereby locally optimizing the reproduction quality for that specific spatial region and reducing comb filtering effects.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the triangulation method adaptive rather than static. The system dynamically selects between different triangulation approaches (such as avoiding horizontal plane crossings or using conventional methods) based on the real-time position of the auditory object and the specific panning scenario, thereby optimizing performance across varying conditions.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If adaptive triangulation avoiding horizontal plane crossings is used, then localization accuracy improves, but device complexity increases

Engineering Contradiction:
Improvespatial reproduction accuracyVSAvoidtriangulation selection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-defining a set of candidate triangulation methods with known characteristics (such as avoiding horizontal plane crossings). During runtime, the system only needs to select from these pre-prepared options based on simple criteria (like whether the auditory object is near the horizontal plane), rather than computing complex triangulations on the fly, thus reducing real-time computational complexity.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If conventional VBAP is used with equally distributed loudspeakers, then horizontal panning works well, but vertical panning and uneven loudspeaker distributions result in reduced audio quality

Engineering Contradiction:
Improveloudspeaker configuration adaptabilityVSAvoidaudio quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies universality by creating a triangulation selection framework that works across multiple loudspeaker configurations (equally distributed, unevenly distributed, different numbers of loudspeakers). The adaptive triangulation method universally handles various scenarios by selecting appropriate triangulation strategies based on the specific configuration and auditory object position, rather than requiring configuration-specific optimizations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3541097B1Spatial sound reproduction using multichannel loudspeaker systems
Publication Date: 2022.04.13 NOKIA TECHNOLOGIES OY
  • EP3541097B1 patent drawingFigure 1
  • EP3541097B1 patent drawingFigure 2
  • EP3541097B1 patent drawingFigure 3a~3b

AI summary

An apparatus for spatial audio signal decoding associated with a plurality of speaker nodes placed within a three dimensional space, the apparatus comprising at least one processor and at least one memory including a computer program code. The at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to determine a nonoverlapping virtual surface arrangement, the virtual surface arrangement comprising a plurality of virtual surfaces with corners positioned at at least three speaker nodes of the plurality of speaker nodes and sides connecting pairs of corners configured to be non-intersecting with at least one defined virtual plane within the three dimensional space. The apparatus is further caused to generate gains for the speaker nodes based on the determined the virtual surface arrangement and apply the gains to at least one audio signal, the at least one audio signal to be positioned within the three dimensional space.