Multi-Channel Audio Coding with Combined Stereo-Spatial Parameters
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Solution Overview
Problem
Existing multi-channel audio coding techniques face challenges in efficiently representing spatial audio parameters and parametric stereo parameters in a bitstream, leading to increased bitrate and compromised audio quality when trying to maintain backward compatibility with legacy decoders.
Innovation Solution
A method that combines spatial and stereo parameters using a combination rule to generate a parametric representation, allowing for efficient encoding and decoding of multi-channel audio signals, where the difference between predicted and actual spatial audio parameters is used to reduce bitrate, while maintaining high-quality reconstruction of both parametric stereo and spatial audio signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial audio parameters and parametric stereo parameters are transmitted separately in a multi-channel audio bitstream, then the audio quality is maintained, but the bitrate increases
Solution Approach 1:
The patent combines spatial audio parameters and parametric stereo parameters into a unified parameter structure within the audio object bitstream. Instead of transmitting separate parameter sets, the encoder integrates both types of parameters into a single coherent representation that can be efficiently decoded by both legacy and advanced decoders, thereby reducing overall bitrate while maintaining audio quality.
Solution Approach 2:
The patent creates a universal parameter structure that serves multiple functions: it provides spatial audio information for advanced decoders while simultaneously containing parametric stereo information compatible with legacy decoders. This multi-functional parameter set eliminates redundancy and allows a single bitstream to support both stereo and multi-channel playback without requiring separate parameter transmissions.
2Adaptability or versatility
If backward compatibility with legacy decoders is maintained, then wide device support is achieved, but the bitrate efficiency decreases
Solution Approach 1:
The patent implements a universal audio object parameter structure that functions across multiple decoder types. The parameter set is designed to be interpreted differently by legacy and advanced decoders, allowing a single bitstream to serve both purposes efficiently. Legacy decoders use the parameters for parametric stereo while advanced decoders utilize them for spatial audio, eliminating the need for separate parameter sets and reducing bitrate.
Solution Approach 2:
The patent segments the parameter information into hierarchical levels within the audio object structure, where core parametric stereo parameters are available to all decoders and additional spatial parameters are provided to advanced decoders. This segmentation allows legacy decoders to function with essential parameters while advanced decoders benefit from enhanced spatial information, optimizing bitrate efficiency across the decoder ecosystem.
3Measurement precision
If both spatial audio and parametric stereo parameters are included in the bitstream, then reconstruction quality is improved, but the overall bitrate increases
Solution Approach 1:
The patent merges spatial audio parameters and parametric stereo parameters into a unified audio object parameter structure. This consolidation eliminates redundant parameter transmissions and allows both types of information to be conveyed more efficiently than separate parameter sets, maintaining high reconstruction quality while reducing overall bitrate.
Solution Approach 2:
The patent transforms the parameter representation by encoding spatial and parametric stereo information in a unified parameter space. By changing how parameters are structured and encoded—using a single coherent parameter set rather than separate parameter groups—the system achieves more efficient bitrate utilization while preserving the ability to reconstruct high-quality audio for both stereo and multi-channel playback.
Data Source
AI summary
A parametric representation of a multi-channel audio signal having parameters suited to be used together with a monophonic downmix signal to calculate a reconstruction of the multi-channel audio signal can efficiently be derived in a stereo-backwards compatible way when a parameter combiner is used to generate the parametric representation by combining a one or more spatial parameters and a stereo parameter resulting in a parametric representation having a decoder usable stereo parameter and an information on the one or more spatial parameters that represents, together with the decoder usable stereo parameter, the one or more spatial parameters.