HOA Audio Rendering for 3DOF+ Spatial Immersion
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Solution Overview
Problem
Current audio rendering technologies in virtual reality (VR), mixed reality (MR), and augmented reality (AR) systems fail to provide immersive audio experiences, particularly in three-dimensional soundfield representations, as they do not effectively account for head movements and translational movements away from the soundfield's center, leading to increased reproduction errors and restricted navigable ranges.
Innovation Solution
The implementation of higher-order ambisonics (HOA) audio rendering techniques that utilize spherical harmonic coefficients to represent soundfields, allowing for three degrees of freedom plus (3DOF+) audio rendering, which adapts the soundfield to account for yaw, pitch, roll, and limited translational head movements by generating an effects matrix based on head tracking information to provide more immersive audio experiences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional audio rendering techniques are used in VR/MR/AR systems, then device complexity is reduced, but audio immersion and soundfield representation accuracy deteriorate
Solution Approach 1:
The patent transforms the soundfield representation by changing parameters through spherical harmonic decomposition, converting traditional audio signals into HOA coefficients that can be adaptively rendered for different head positions and orientations, thereby improving soundfield accuracy while managing complexity through mathematical transformation
Solution Approach 2:
The patent introduces an intermediary processing stage that decomposes the soundfield into spherical harmonic coefficients, which then serve as a flexible intermediate representation that can be rendered to various speaker configurations and adapted to user head movements, bridging the gap between fixed audio formats and dynamic spatial audio requirements
2Reliability
If audio rendering does not account for head movements, then device complexity is reduced, but audio immersion and user experience deteriorate
Solution Approach 1:
The patent implements dynamic audio rendering that continuously adapts to user head movements by updating the rendering parameters based on real-time head tracking data, allowing the soundfield to move with the user and maintain immersion as the user navigates through the virtual environment
Solution Approach 2:
The patent incorporates feedback from head tracking sensors to continuously adjust the audio rendering parameters, creating a closed-loop system where user head position and orientation information feeds back into the rendering process to maintain accurate spatial audio correspondence with the user's viewpoint
3Measurement precision
If listener translation from soundfield center is not accounted for, then device complexity is reduced, but reproduction accuracy and navigable range deteriorate
Solution Approach 1:
The patent performs preliminary decomposition of the soundfield into spherical harmonic coefficients at the content creation stage, enabling subsequent efficient rendering and translation operations without requiring complex real-time processing, as the mathematical foundation is already established
Solution Approach 2:
The patent extends the audio rendering from traditional 3DOF (rotational only) to 3DOF+ by incorporating translational dimension compensation, allowing accurate soundfield reconstruction even when the user moves away from the soundfield center, effectively adding another degree of freedom to the rendering capability
Data Source
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AI summary
In general, techniques are described for adapting higher order ambisonic audio data to include three degrees of freedom plus effects. An example device configured to perform the techniques includes a memory, and a processor coupled to the memory. The memory may be configured to store higher order ambisonic audio data representative of a soundfield. The processor may be configured to obtain a translational distance representative of a translational head movement of a user interfacing with the device. The processor may further be configured to adapt, based on the translational distance, higher order ambisonic audio data to provide three degrees of freedom plus effects that adapt the soundfield to account for the translational head movement, and generate speaker feeds based on the adapted higher order ambient audio data.