Perception-Based Audio Parameter Quantization for Bitrate Reduction
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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
Implementing a non-uniform scalar quantization scheme for audio parameters, where smaller step-sizes are used in sensitive ranges and larger step-sizes in less sensitive ranges, along with a scaling function to adjust quantization of the second parameter, reducing average bit consumption without compromising 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 ranges of the first parameter based on human sound perception sensitivity. Smaller step-sizes are used in ranges where perception is most sensitive, and larger step-sizes are used where perception is less sensitive. This local differentiation of quantization quality allows efficient bit stream compression while preserving perceptually important information.
2Loss of information
If low compression is applied to the bit stream, then audio quality is maintained, but bit stream capacity deteriorates due to excessive data volume
Solution Approach 1:
The patent transforms the quantization approach by introducing a scaling factor that modifies the step-sizes of the second parameter based on the value of the first parameter. This parameter change allows the system to adapt the quantization precision dynamically, using coarser quantization (larger step-sizes) when appropriate and finer quantization (smaller step-sizes) when necessary, thereby reducing overall bit stream capacity while maintaining audio quality.
3Device complexity
If uniform quantization is used for all parameter ranges, then device complexity is reduced, but measurement precision deteriorates in sensitive perception ranges
Solution Approach 1:
The patent implements non-uniform quantization with perception-based step-sizes for the first parameter and scaling-factor-based step-sizes for the second parameter. This local quality approach maintains relatively simple device complexity while significantly improving measurement precision in human sound perception sensitive ranges compared to uniform quantization.
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.