Reverberator Adjustment Using Source Directivity for Spatial Audio
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Solution Overview
Problem
Existing spatial audio reproduction systems fail to accurately model and reproduce the effect of sound source directivity on reverberation, leading to suboptimal reverberation quality, especially at high frequencies, due to the assumption of omnidirectional sound sources.
Innovation Solution
The system determines directivity-influenced reverberation gains by analyzing directivity data for multiple directions, estimating a directivity model, and applying spatial averaging to generate frequency-dependent gain data, which is then used to adjust reverberators based on room parameters, ensuring accurate reproduction of late reverberation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uncorrelated noise sequences are used in each channel to produce mutually incoherent reverberant signals, then the reverberation can be reproduced with simple acoustic characteristics, but the reverberation is perceived to be similar to all directions and lacks directional accuracy
Solution Approach 1:
The patent applies local quality by assigning different acoustic characteristics to different spatial regions. Specifically, it uses direction-dependent impulse responses and spatially-varying gain factors to make the reverberation properties differ across different directions, thereby achieving directionally-accurate reverberation while maintaining computational efficiency through a unified rendering framework.
2Measurement precision
If directionally-dependent reverberation is reproduced accurately, then spatial impression accuracy is improved, but computational complexity increases due to the need for separate processing of multiple directions
Solution Approach 1:
The patent implements universality by creating a unified reverberation rendering system that handles both omnidirectional and directional sources through a single computational framework. The approach uses a set of impulse responses that can be selectively applied based on source direction, allowing the same system to efficiently process multiple types of sound sources without requiring separate dedicated processing paths for each case.
Solution Approach 2:
The patent applies preliminary action by pre-computing and storing directionally-dependent impulse responses and gain factors before actual audio rendering. This allows the system to quickly lookup and apply appropriate reverberation characteristics during real-time processing, significantly reducing computational complexity while maintaining high spatial accuracy.
3Productivity
If high-frequency reverberation is reproduced using omnidirectional assumption, then processing is computationally efficient, but the reverberation quality deteriorates due to inaccurate modeling of directional sound sources
Solution Approach 1:
The patent implements partial action by selectively applying directionally-dependent processing only where necessary. Specifically, it uses gain factors that are adjusted based on source direction and frequency, applying full directional processing at high frequencies where it matters most while maintaining efficiency through a unified framework that can fallback to simpler processing when appropriate.
Data Source
AI summary
An apparatus for assisting spatial rendering for room acoustics, the apparatus including means configured to: obtain directivity data having an identifier, wherein the directivity data includes data for at least two separate directions; obtain at least one room parameter; determine information associated with the directivity data; determine gain data based on the determined information; determine averaged gain data based on the gain data; and generate a bitstream defining a rendering, the bitstream including the averaged gain data and the at least one room parameter such that at least one audio signal associated with the identifier is configured to be rendered based on the at least one room parameter and the determined averaged gain data.