Spherical-Harmonic Audio Rendering for 3DOF and 6DOF VR

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Solution Overview

Problem

Existing VR, AR, and MR technologies struggle to provide immersive audio experiences that account for six degrees of freedom, particularly in devices that support fewer than six degrees of freedom, leading to limited auditory immersion.

Innovation Solution

The use of spherical harmonic coefficients (SHC) and higher-order ambisonic (HOA) representations to encode and render audio data, enabling rendering of audio that accounts for six degrees of freedom on devices that support fewer degrees of freedom, by generating metadata that adapts audio rendering based on user movement and location.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If audio data is encoded with six degrees of freedom for immersive audio experience, then auditory immersion is improved, but device complexity increases

Engineering Contradiction:
Improveaudio rendering capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The audio data is divided into multiple audio adaptation sets, each associated with different regions and encoded at different bit rates. This segmentation allows the system to provide high-quality 6DOF audio when needed while maintaining compatibility with devices that have fewer degrees of freedom, thus resolving the contradiction between adaptability and complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system is designed to support multiple degrees of freedom (3DOF, 6DOF) within a single unified framework. The audio encoder can generate adaptation sets that work on devices with varying capabilities, making the system universal and reducing the need for separate complex systems for different device types

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

2Measurement precision

If audio data is encoded at high bit rates for quality, then audio quality is improved, but data size increases

Engineering Contradiction:
Improveaudio qualityVSAvoiddata size
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The audio stream is segmented into multiple adaptation sets with different bit rates. This allows the system to transmit high-quality audio data when needed while providing lower-quality alternatives for devices with limited bandwidth or storage, effectively managing the trade-off between quality and data quantity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects and switches between different audio adaptation sets based on the user's head orientation and the capabilities of the playback device. This dynamic adaptation allows the system to optimize the balance between audio quality and data size in real-time

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If real-time audio adaptation is implemented for user movement, then audio immersion is improved, but processing time increases

Engineering Contradiction:
Improveaudio adaptation capabilityVSAvoidprocessing time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system pre-encodes multiple audio adaptation sets in advance during the content creation phase. This preliminary preparation eliminates the need for real-time encoding, reducing processing time while maintaining the ability to adapt audio to user movement and device capabilities

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses dynamic selection mechanisms to switch between pre-encoded audio adaptation sets based on user head orientation and device capabilities. This dynamic switching provides real-time adaptation without the computational burden of real-time encoding, thus reducing processing time

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4372530B1Six degrees of freedom and three degrees of freedom backward compatibility
Publication Date: 2025.07.30 QUALCOMM INC
  • EP4372530B1 patent drawingFigure 1
  • EP4372530B1 patent drawingFigure 2A
  • EP4372530B1 patent drawingFigure 2B

AI summary

A device and method for backward compatibility for virtual reality (VR), mixed reality (MR), augmented reality (AR), computer vision, and graphics systems. The device and method enable rendering audio data with more degrees of freedom on devices that support fewer degrees of freedom. The device includes memory configured to store audio data representative of a soundfield captured at a plurality of capture locations, metadata that enables the audio data to be rendered to support N degrees of freedom, and adaptation metadata that enables the audio data to be rendered to support M degrees of freedom. The device also includes one or more processors coupled to the memory, and configured to adapt, based on the adaptation metadata, the audio data to provide the M degrees of freedom, and generate speaker feeds based on the adapted audio data.