Ambisonic Audio Decoding with Sector-Based DoA and Diffuseness
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Solution Overview
Problem
Conventional Ambisonic audio coding methods assume a single direction of arrival (DoA) and diffuseness for the whole space, failing to accurately model realistic sound scenes with multiple sound sources, leading to suboptimal perceptual quality and stability in spatial audio rendering.
Innovation Solution
A sector-based DirAC system that utilizes higher-order channels to estimate multiple DoAs and diffuseness within spatial sectors, integrating these parameters into existing first-order DirAC systems for improved sound field modeling and robustness, allowing seamless switching between coding scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Ambisonic audio coding methods are used with a single DoA and diffuseness model, then the system structure remains simple and robust, but the accuracy of sound field modeling deteriorates for realistic sound scenes with multiple sound sources
Solution Approach 1:
The audio scene is divided into multiple spatial sectors, each with its own DoA and diffuseness parameters. This segmentation allows the system to model multiple sound sources independently while maintaining a manageable structure for each sector.
Solution Approach 2:
The patent transitions from first-order Ambisonics to higher-order Ambisonics (HOA), adding an additional dimension of spatial resolution. This enables the system to represent multiple DoAs and diffuseness values simultaneously, improving modeling accuracy without fundamentally changing the overall system architecture.
2Measurement precision
If higher-order Ambisonics channels are used to represent multiple DoAs, then the measurement precision of sound field parameters improves, but the device complexity and processing requirements increase
Solution Approach 1:
The system uses higher-order Ambisonics channels (excessive action) to capture multiple DoAs, but then applies selective processing only to sectors that contain directional sound sources. This partial processing approach reduces overall computational complexity while maintaining high measurement precision where needed.
Solution Approach 2:
The patent implements dynamic switching between first-order and higher-order processing modes. The system adapts its complexity level based on the audio scene characteristics, using HOA only when multiple DoAs are detected, thereby optimizing the balance between precision and processing requirements.
3Reliability
If sector-based processing with multiple DoAs is implemented, then the perceptual quality of spatial audio rendering improves, but the compatibility with existing first-order DirAC systems deteriorates
Solution Approach 1:
The patent designs the HOA-based sector processing system to be compatible with existing first-order DirAC infrastructure. The higher-order processing acts as an enhancement layer that can operate independently or in conjunction with first-order methods, allowing the system to serve multiple coding scenarios and maintain versatility.
Solution Approach 2:
The system dynamically adapts its operating mode based on the audio content and coding requirements. It can switch between first-order and higher-order processing, allowing seamless integration with existing systems while providing enhanced perceptual quality when needed.
Data Source
AI summary
An audio signal representation decoding unit for generating a decompressed ambisonic spatial audio signal representation from a compressed ambisonic spatial audio signal representation representing an audio signal, including: sector decoding paths, each configured to decode a directional sector signal of the decompressed ambisonic spatial audio signal representation in each spatial sector by applying, to at least one transport channel, or a sector signal derived from the at least one transport channel, directional parameter(s) and a sector diffuseness parameter(s) of a spatial sector, a global diffuseness signal decoding path to derive a global diffuseness signal by applying, to the at least one transport channel, a global diffuseness parameter, or other information on the global diffuseness of the audio signal, a global diffuseness signal inserter to combine decoded directional sector signals and the global diffuseness signal, to output the decompressed ambisonic spatial audio signal representation.