Non-Uniform Audio Parameter Quantization for Lower Stereo Bitrates
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Solution Overview
Problem
Existing parametric stereo coding methods face challenges in balancing bit stream compression and audio quality, as high compression leads to unacceptable sound quality due to information loss, while low compression results in capacity issues.
Innovation Solution
The proposed method employs non-uniform scalar quantization schemes for audio parameters, using smaller step-sizes where human sound perception is most sensitive and larger step-sizes where it is less sensitive, and applies a scaling function to adjust the quantization of the second parameter based on the first, to reduce bit consumption without degrading sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high compression is applied to the bit stream, then bit stream capacity is improved, but audio quality deteriorates due to information loss
Solution Approach 1:
The patent applies non-uniform quantization where different step-sizes are used for different parameter ranges based on human auditory sensitivity. More bits are allocated to parameters in ranges where human perception is most sensitive, while fewer bits are used for less sensitive ranges. This local optimization of bit allocation maintains audio quality in critical regions while reducing overall bit stream requirements.
Solution Approach 2:
The patent transforms the uniform quantization approach into a non-uniform quantization scheme by changing the quantization step-sizes based on the parameter values and human perception characteristics. This parameter transformation allows the system to achieve better perceptual audio quality at lower bit rates by adapting the quantization granularity to the importance of different parameter regions.
2Loss of information
If low compression is applied to the bit stream, then audio quality is maintained, but bit stream capacity is reduced causing capacity problems
Solution Approach 1:
Instead of uniformly preserving all parameter information with high precision, the patent selectively applies finer quantization only to parameter regions where human perception is most sensitive. This localized precision preservation maintains perceptual audio quality while significantly reducing the overall bit stream capacity requirements compared to uniform high-precision quantization.
3Device complexity
If uniform quantization is used for all parameters, then device complexity is reduced, but manufacturing precision of audio quality is insufficient
Solution Approach 1:
The patent implements non-uniform quantization with variable step-sizes that adapt to different parameter ranges and human perception characteristics. This approach achieves superior audio parameter precision by using finer quantization steps in sensitive regions and coarser steps in less sensitive regions, while maintaining relatively simple encoder and decoder structures that do not require complex vector quantizers or adapted entropy coding.
Data Source
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AI summary
The present disclosure provides methods, devices and computer program products for non-uniform quantization of parameters relating to parametric spatial coding of audio signals. The disclosure further relates to a method and apparatus for reconstructing an audio object in an audio decoding system taking the non-uniformly quantized parameters into account. According to the disclosure, such an approach renders it possible to reduce bit consumption without substantially reducing the quality of the reconstructed audio object.