Seamless rendering of audio elements with both interior and exterior representations
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Solution Overview
Problem
Existing methods for rendering spatially-bounded audio elements with interior and exterior representations suffer from abrupt transitions and unwanted frequency cancellations due to correlated virtual loudspeakers, leading to comb-filtering effects.
Innovation Solution
A method is introduced to align and interpolate the positions and signals of virtual loudspeakers between interior and exterior representations, reusing a subset of speakers to maintain a smooth transition without increasing speaker count, using techniques like Ambisonics signal rotation and linear interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple duplicate copies of mono audio object are created at positions around the mono object's position to create spatially homogeneous object, then the perception of spatial extent is improved, but the device complexity and computational load increase
Solution Approach 1:
The patent combines the interior representation (listener-centric audio signal) and exterior representation (source-centric audio signal) into a unified rendering system. By merging these two representations and using a transition region with cross-fading, the system achieves smooth transitions without requiring separate complete speaker sets for each representation, thus reducing overall complexity while maintaining spatial extent perception.
Solution Approach 2:
The transition region serves multiple functions: it acts as a buffer zone for cross-fading between interior and exterior representations, and it allows the same set of virtual loudspeakers to serve both interior and exterior rendering purposes during the transition, reducing the total number of speakers needed compared to having dedicated speaker sets for each representation.
2Stability of the object's composition
If interior and exterior representations are rendered in parallel with simple cross-fade transition, then transition smoothness is improved, but comb-filtering artifacts and frequency cancellations occur due to correlated virtual loudspeakers
Solution Approach 1:
The patent extracts and removes the problematic correlated virtual loudspeakers from the transition region. By identifying and taking out the duplicate speakers that cause comb-filtering, the system eliminates frequency cancellations while preserving the smooth cross-fade transition between interior and exterior representations.
Solution Approach 2:
The transition region acts as an intermediary zone that mediates between interior and exterior representations. Within this region, the system carefully manages speaker activation to avoid direct correlation between interior and exterior speakers, using the transition region as a buffer that prevents harmful interference while enabling smooth transitions.
3Manufacturing precision
If the number of virtual loudspeakers is increased to improve transition quality, then audio quality is improved, but device complexity and computational resources increase
Solution Approach 1:
The patent implements dynamic speaker activation based on listener position relative to the audio object. The system dynamically adjusts which speakers are active (interior, exterior, or transition region speakers) as the listener moves, allowing high audio quality with fewer total speakers by optimizing speaker usage according to the current rendering region rather than using all speakers continuously.
Data Source
AI summary
A method for spatial audio rendering of an audio element having an extent. The method includes determining that a listener is within a transition region. The method also includes determining a first interior rendering with an interior set of virtual loudspeakers. The method also includes determining an exterior rendering with an exterior set of virtual loudspeakers, the exterior set of virtual loudspeakers comprising first and second virtual loudspeakers. The method also includes, in response to determining that the listener is within the transition region, determining a transition rendering, the transition rendering including the interior set of virtual loudspeakers with two loudspeakers in the interior set of virtual loudspeakers replaced by third and fourth virtual loudspeakers, the third and fourth virtual loudspeakers being based on the first and second virtual loudspeakers of the exterior set of virtual loudspeakers. The method also includes rendering the transition rendering for the listener.