Multi-Channel Audio Decoder for Post-Rendering Correlation Adjustment
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Solution Overview
Problem
Existing audio encoding and decoding technologies struggle to efficiently handle 3-dimensional audio scenes, particularly in terms of correlation and covariance characteristics, often introducing artifacts when decorrelating signals before rendering.
Innovation Solution
A multi-channel audio decoder that derives decorrelated audio signals from rendered audio signals and combines them with the original signals to adjust correlation and covariance characteristics post-rendering, using parametric reconstruction and side information to enhance audio quality and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If decorrelation is performed before rendering, then correlation characteristics can be adjusted, but artifacts are introduced and processing complexity increases
Solution Approach 1:
The encoder performs decorrelation of the audio signal before encoding, so that the decorrelated signal is available at the decoder without requiring complex post-rendering processing. This preliminary action avoids introducing artifacts during decoding while maintaining the ability to adjust correlation characteristics.
Solution Approach 2:
Instead of performing decorrelation after rendering (which introduces artifacts), the invention applies decorrelation before encoding/rendering. This inversion of the processing order eliminates the harmful artifacts while achieving the same correlation adjustment effect.
2Adaptability or versatility
If multiple decorrelators are used to handle 3D audio scenes, then correlation adjustment capability is improved, but device complexity increases
Solution Approach 1:
A single decorrelator is designed to perform multiple functions: it can process different types of audio signals, handle various correlation characteristics, and adapt to different rendering scenarios. This multi-functional approach eliminates the need for multiple specialized decorrelators while maintaining comprehensive correlation adjustment capability for 3D audio scenes.
Solution Approach 2:
The decorrelator uses parameter changes (such as correlation coefficients, decorrelation factors) to adapt its behavior to different audio scenarios. By adjusting these parameters dynamically, a single decorrelator can handle diverse 3D audio content without requiring multiple fixed decorrelator configurations.
3Productivity
If decorrelation is performed before rendering, then processing efficiency is improved, but correlation characteristics cannot be precisely adjusted post-rendering
Solution Approach 1:
The system incorporates feedback mechanisms where the encoder analyzes the audio signal's correlation characteristics and adjusts the decorrelation parameters accordingly. This feedback loop ensures that the decorrelated signal maintains precise correlation characteristics suitable for the intended rendering application, while still benefiting from the efficiency of pre-rendering decorrelation.
Data Source
AI summary
A multi-channel audio decoder for providing at least two output audio signals on the basis of an encoded representation is configured to render a plurality of decoded audio signals, which are obtained on the basis of the encoded representation, in dependence on one or more rendering parameters, to obtain a plurality of rendered audio signals. The multi-channel audio decoder is configured to derive one or more decorrelated audio signals from the rendered audio signals, and to combine the rendered audio signals, or a scaled version thereof, with the one or more decorrelated audio signals, to obtain the output audio signals. A multi-channel audio encoder provides a decorrelation method parameter to control an audio decoder.