Higher Order Ambisonics Audio Data Structure for Immersive 3D Sound
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Ambisonics file formats are inadequate for storing multiple sound field descriptions and do not support Higher Order Ambisonics (HOA) orders greater than 3, lacking essential information for next-generation decoders and efficient data storage.
Innovation Solution
A new file format that stores one or more HOA signals and directional mono signals, including vital information like wave type, reference radius, and metadata, allowing for Ambisonics orders greater than 3 and flexible storage of data with different PCM-word sizes, enabling efficient storage and decoding of complex audio content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing Ambisonics file formats (like B-Format) are used, then storage of HOA data up to order 3 is enabled, but support for HOA orders greater than 3 is lost and file size is restricted to 4 GB
Solution Approach 1:
The file format is segmented into distinct functional components: container structure for multiple sound field descriptions, metadata sections for decoder parameters (wave type, reference radius), and data sections for HOA coefficients. This segmentation allows the format to support arbitrary HOA orders by simply adding more coefficients without requiring a complete format redesign, thereby resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The patent extends the traditional 2D/3D Ambisonics framework by introducing a fourth dimension through support for HOA orders greater than 3. This is achieved by adding new data structures that can accommodate higher-order spherical harmonic coefficients, enabling the format to represent more complex spatial audio scenes while maintaining backward compatibility with lower-order content.
2Loss of information
If B-Format is used for storing HOA data, then file storage is enabled, but essential information for next-generation decoders (wave type, reference radius) is missing
Solution Approach 1:
The patent incorporates all necessary decoder information (wave type, reference radius, normalization factors) directly into the file format during the encoding stage. This preliminary inclusion of metadata ensures that next-generation decoders have all required parameters available before playback, eliminating information loss while maintaining implementation simplicity through a unified file structure that bundles all necessary data together.
3Measurement precision
If uniform spatial distribution of audio objects is required for HOA encoding, then accurate 3D spatial reproduction is achieved, but the number of encodable objects is limited to M=(N+1)²
Solution Approach 1:
The patent applies local quality by allowing different spatial distributions and encoding strategies for different regions of the audio scene. Rather than requiring uniform distribution of all M=(N+1)² objects throughout the entire sphere, the format enables concentrated spatial arrangements where objects can be densely packed in specific regions (such as the frontal area for cinema applications) while maintaining accurate localization within those regions. This resolves the contradiction by permitting non-uniform distributions that match practical application requirements.
Data Source
AI summary
The invention is related to a data structure for Higher Order Ambisonics HOA audio data, which data structure includes 2D or 3D spatial audio content data for one or more different HOA audio data stream descriptions. The HOA audio data can have on order of greater than ‘3’, and the data structure in addition can include single audio signal source data and/or microphone array audio data from fixed or time-varying spatial positions.