Non-Uniform Audio Parameter Quantization for Low-Bit Spatial Coding
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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 complex calculations or 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 quantization based on perceived sensitivity, reducing average 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 different quantization step sizes to different parameter ranges based on perceptual sensitivity. Small step sizes are used for parameters in ranges where human hearing is most sensitive, while larger step sizes are used in less sensitive ranges. This local adaptation of quantization precision maintains audio quality in critical regions while allowing greater compression in less critical regions, thus resolving the contradiction between compression and quality.
Solution Approach 2:
The patent changes the quantization parameters (step sizes) dynamically based on the parameter values and their perceptual importance. By adapting the quantization step size according to the specific parameter range and human auditory sensitivity, the system optimizes the balance between bit stream compression and audio quality preservation.
2Loss of information
If complex quantization schemes are used, then audio quality is improved, but device complexity increases
Solution Approach 1:
Instead of using a globally complex quantization scheme, the patent applies simple scalar quantization with locally adapted step sizes. Each parameter is quantized independently with a step size tailored to its specific range and perceptual importance, avoiding the need for complex vector quantizers while maintaining high audio quality.
Solution Approach 2:
The patent simplifies the overall system complexity by changing from fixed uniform quantization to adaptive scalar quantization with varying step sizes. This approach maintains perceptual quality through parameter adaptation without requiring complex quantization algorithms or large codebooks.
Data Source
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.