Audio Ambience Modification for Free-Viewpoint Playback
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Solution Overview
Problem
Current spatial audio playback systems face challenges in accurately modifying sound source directions for users moving within six degree of freedom (6dof) environments, especially when the user is between or far from microphone array positions, leading to inaccuracies in audio source localization.
Innovation Solution
A method and apparatus that track user movement and determine the probability of error in sound source direction estimates, applying audio ambience based on user displacement from the nearest microphone array and the probability of error, using a combination of audio processing techniques such as directional audio coding and ambience modification to ensure perceptually correct sound source positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 3dof content is recorded in several locations and interpolated between those locations, then spatial audio playback can be implemented, but accuracy of sound source direction estimation deteriorates when user is between or far from microphone array positions
Solution Approach 1:
The patent introduces an intermediary processing stage between the microphone array recordings and the final audio playback. This intermediary system uses audio ambience modification techniques to bridge the gap when the user is positioned between or far from microphone array locations, thereby maintaining direction estimation accuracy without requiring dense microphone array placement throughout the entire 6dof environment.
Solution Approach 2:
The patent dynamically changes audio parameters based on user position and displacement from microphone arrays. By modifying audio ambience parameters (such as reverb, diffusion, and spatial characteristics) according to the user's location and the probability of error in direction estimates, the system adapts the audio output to maintain accuracy across varying spatial conditions.
2Measurement precision
If numerous microphone arrays are deployed to improve direction estimation accuracy, then sound source localization improves, but device complexity increases
Solution Approach 1:
The audio ambience modification system acts as an intermediary that compensates for the limitations of sparse microphone array placement. Instead of requiring numerous microphone arrays to achieve high direction estimation accuracy, the system uses computational audio processing to synthesize accurate spatial audio characteristics, thereby reducing hardware complexity while maintaining or improving measurement precision.
Solution Approach 2:
The patent replaces the mechanical approach of using numerous physical microphone arrays with a computational approach. By using audio ambience modification algorithms that process signals from fewer microphone arrays through sophisticated signal processing, the system achieves accurate sound source localization without the mechanical complexity of deploying and managing numerous microphone arrays throughout the 6dof space.
3Measurement precision
If audio ambience is applied based on user displacement and probability of error, then perceptual correctness of sound sources improves, but processing time increases
Solution Approach 1:
The system performs preliminary calculations of user displacement from microphone arrays and probability of error in direction estimates before applying audio ambience modification. By pre-computing these parameters and using them to guide the audio processing, the system optimizes the timing and efficiency of audio ambience application, reducing overall processing time while maintaining perceptual correctness.
Solution Approach 2:
The patent implements dynamic audio ambience modification where the degree of ambience application is adjusted in real-time based on user displacement and direction estimation accuracy. The system dynamically adapts the audio processing intensity and characteristics to the current spatial conditions, applying more processing when needed (high error probability) and less processing when accuracy is sufficient, thereby optimizing processing time while maintaining perceptual quality.
Data Source
AI summary
A method including accessing, by a user device, a location corresponding to at least one microphone array in a content of a free-viewpoint audio environment. The method includes tracking user movement of a user based on a user position in the content of the free-viewpoint audio environment, determining a probability of error in a direction estimate from at least one part of an audio signal; and applying audio ambience to the at least one part of the audio signal based on the user displacement from the nearest microphone array of the at least one microphone array and the probability of error in the direction estimate from the at least one part of the audio signal.