Audio Codec Quantization for Preserving Localization Cues
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Solution Overview
Problem
Audio encoders, such as MP3 and opus encoders, maximize quantization for compression savings but often flatten audio dynamics, reducing artistic expression and sound localization cues, leading to a less differentiated listening experience due to lossy compression.
Innovation Solution
Implementing a process that applies acoustic perception algorithms like dissonance, localization, and salience modeling to adjust quantization parameters, minimizing the impact of quantization on listening experience by modeling human hearing efficiency and resolution at different frequencies and masking conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If quantization is maximized for compression savings, then compression efficiency is improved, but audio dynamics and localization cues are flattened
Solution Approach 1:
The patent applies different quantization strengths to different audio components based on their perceptual importance. Acoustic perception algorithms identify and protect critical elements (transients, localization cues, dissonant intervals) from aggressive quantization while allowing less critical components to be compressed more heavily. This local differentiation preserves audio dynamics and localization cues while maintaining compression efficiency.
Solution Approach 2:
The system dynamically adjusts quantization parameters based on acoustic perception analysis. By changing quantization strength parameters selectively across different frequency bands, time windows, and audio components, the system optimizes the balance between compression efficiency and preservation of perceptually important features like transients and localization cues.
2Loss of substance
If quantization is maximized for compression savings, then compression efficiency is improved, but sound localization cues are reduced
Solution Approach 1:
The patent identifies specific audio components that carry localization information (interaural time differences, interaural level differences, spectral cues) and applies reduced quantization strength to these components. This selective protection ensures localization cues are preserved while other less critical audio content undergoes stronger compression.
Solution Approach 2:
The system uses acoustic perception algorithms to analyze the audio content and provide feedback about which components contain critical localization information. This feedback loop allows the quantization process to adaptively protect localization cues while maintaining overall compression efficiency.
3Loss of substance
If quantization is maximized for compression savings, then compression efficiency is improved, but artistic expression is reduced
Solution Approach 1:
The patent protects perceptually important features such as transients, dissonant intervals, and dynamic variations from aggressive quantization while allowing less critical components to be compressed more heavily. This selective approach preserves the artistic expression and emotional impact of the audio while maintaining compression efficiency.
Data Source
AI summary
A method including receiving a plurality of audio channels based on an audio stream, applying a model based on at least one acoustic perception algorithm to the plurality of audio channels to generate a first modelled audio stream, quantizing the plurality of audio channels using a first set of quantization parameters, dequantizing the quantized plurality of audio channels using the first set of quantization parameters, applying the model based on at least one acoustic perception algorithm to the dequantized plurality of audio channels to generate a second modelled audio stream, comparing the first modelled audio stream and the second modelled audio stream, in response to determining the comparison of the first modelled audio stream and the second modelled audio stream does not meet a criterion, generating a second set of quantization parameters, and quantizing the plurality of audio channels using the second set of quantization parameters.