Multi-Channel Audio Coding With Scalable Frequency-Layer Decoding
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Solution Overview
Problem
Existing multi-channel audio encoding technologies fail to efficiently scale the quality of the encoded audio signal with available bit rate or decoder complexity, limiting adaptability to varying transmission bandwidth and decoder complexity.
Innovation Solution
A method of encoding multi-channel audio signals by generating information in multiple portions, allowing for scalable decoding quality based on available bit rate and decoder complexity, where a base layer provides basic quality and optional enhancement layers improve quality within specific frequency ranges, ensuring reliable decoding even at low bit rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single channel audio signal with parametric information is used to represent multi-channel audio, then transmission bandwidth is reduced, but decoding quality cannot be scaled with available bit rate or decoder complexity
Solution Approach 1:
The information is divided into multiple portions, each corresponding to different frequency regions of the multi-channel audio signal. This segmentation allows the decoder to selectively process portions based on available bit rate and complexity, enabling quality scaling while maintaining bandwidth efficiency.
Solution Approach 2:
The patent introduces a new dimension of scalability by organizing parametric information across multiple frequency regions, allowing the system to adapt decoding quality along a continuum rather than offering fixed quality levels. This enables flexible quality scaling independent of transmission bandwidth constraints.
2Adaptability or versatility
If multiple portions of information for different frequency regions are encoded, then decoding quality can be scaled, but device complexity increases
Solution Approach 1:
The decoder is designed to dynamically select which portions of information to process based on available computational resources and desired quality level. This dynamic adaptability allows complex multi-region processing when resources permit, while automatically simplifying to lower-complexity operation when resources are constrained.
Solution Approach 2:
Different frequency regions can be processed with different levels of detail and complexity according to their perceptual importance and available resources. Critical frequency regions receive more sophisticated processing while less critical regions use simpler processing, optimizing the complexity-quality tradeoff.
3Reliability
If parametric information for full bandwidth is transmitted, then audio quality is maintained, but bit rate consumption increases
Solution Approach 1:
The system transmits complete parametric information for all frequency regions but allows the decoder to process only the necessary portions based on available bit rate. This partial processing approach maintains the option for full quality when resources allow while enabling quality adaptation when bit rate is constrained.
Solution Approach 2:
The patent changes the parameter organization from a single comprehensive parametric set to multiple frequency-region-specific parametric sets. This reorganization enables selective transmission and processing of parametric information, allowing bit rate adaptation while preserving the ability to reconstruct full-quality audio when resources permit.
Data Source
AI summary
Multi-channel audio signals are coded into a monaural audio signal and information allowing to recover the multi-channel audio signal from the monaural audio signal and the information. The information is generated by determining a first portion of the information for a first frequency region of the multi-channel audio signal, and by determining a second portion of the information for a second frequency region of the multi-channel audio signal. The second frequency region is a portion of the first frequency region and thus is a sub-range of the first frequency region. The information is multi-layered enabling a scaling of the decoding quality versus bit rate.