Interpolated Matrices for Smooth Multichannel Audio Rendering
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Solution Overview
Problem
Current audio processing systems face challenges in efficiently rendering multichannel audio programs, particularly object-based audio programs, due to the complexity and computational cost associated with rendering a large number of channels, which can result in artifacts like zipper noise from discontinuous matrix updates.
Innovation Solution
The method involves determining a first cascade of primitive matrices that implement an initial mix of audio content and using interpolation values to generate a sequence of updated primitive matrices, allowing for smooth interpolation between rendering matrices over time, thereby reducing artifacts and improving rendering accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If object-based audio programs with many channels are rendered using conventional methods, then spatial accuracy and audio fidelity are improved, but computational complexity and processing cost increase significantly
Solution Approach 1:
The rendering process is segmented into two distinct phases: an offline preprocessing phase where primitive matrices are pre-computed and stored, and an online rendering phase where these pre-computed matrices are interpolated and applied in real-time. This segmentation separates the computationally intensive matrix calculations from the time-critical rendering operations, reducing real-time computational complexity while preserving spatial accuracy
Solution Approach 2:
Primitive matrices are pre-computed and stored during an offline preprocessing phase before actual rendering occurs. These pre-computed matrices capture the spatial relationships and acoustic characteristics needed for accurate rendering, allowing the online phase to focus only on interpolation and application, thereby significantly reducing online computational complexity
2Measurement precision
If rendering matrices are updated frequently to track rapidly varying audio object positions, then positional accuracy is improved, but discontinuities and zipper noise artifacts occur
Solution Approach 1:
An interpolation function serves as an intermediary between discrete primitive matrices defined at different times. This intermediary continuously transforms the audio signal by combining multiple primitive matrices according to the interpolation function, ensuring smooth transitions and eliminating discontinuities that would otherwise occur with direct switching between matrices
Solution Approach 2:
The interpolation function ensures continuous transformation of the audio signal between primitive matrices, maintaining uninterrupted and smooth rendering even as audio objects move rapidly. This continuous action prevents the discontinuities and zipper noise that would result from abrupt matrix switching
3Measurement precision
If the number of audio channels is increased for object-based audio, then spatial resolution and audio quality are improved, but processing time and computational resources increase
Solution Approach 1:
The processing is segmented into offline preprocessing where complex matrix calculations are performed when time is not critical, and online rendering where pre-computed matrices are efficiently interpolated and applied in real-time. This segmentation enables high spatial resolution rendering with reduced processing time during actual playback
Solution Approach 2:
Instead of computing complex rendering matrices in real-time, the system creates and stores simplified primitive matrices during offline preprocessing that capture the essential spatial characteristics. These copied representations are then reused and interpolated during online rendering, dramatically reducing processing time while maintaining spatial resolution
Data Source
AI summary
Methods which uses interpolated primitive matrices to decode encoded audio to recover (losslessly) content of a multichannel audio program and/or to recover at least one downmix of such content, and encoding methods for generating such encoded audio. In some embodiments, a decoder performs interpolation on a set of seed primitive matrices to determine interpolated matrices for use in rendering channels of the program. Other aspects are a system or device configured to implement any embodiment of the method.