Spatial Audio Parameter Quantization Using Energy-Dependent Rules

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Solution Overview

Problem

Existing multi-channel audio compression techniques, such as Binaural Cue Coding and Parametric Stereo, inefficiently represent spatial audio parameters, leading to sub-optimal quantization and increased bandwidth usage for channels with low energy, which are often masked during playback, resulting in wasted bandwidth and reduced perceptual quality.

Innovation Solution

A parameter quantizer and dequantizer system that generates energy-dependent quantization rules based on the energy measures of individual channels and the multi-channel signal, allowing for coarser quantization of low-energy channels without affecting perceptual quality, as high-energy signals mask low-energy signals during playback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uniform quantization is applied to all channels, then quantization simplicity is maintained, but bandwidth efficiency deteriorates due to wasted bits on low-energy masked channels

Engineering Contradiction:
Improvequantization simplicityVSAvoidbandwidth efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent applies different quantization rules to different channels based on their energy levels and masking conditions. High-energy channels receive finer quantization while low-energy masked channels receive coarser quantization, optimizing bandwidth usage according to local signal characteristics rather than applying uniform quantization across all channels.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If coarse quantization is applied to low-energy channels, then bandwidth efficiency improves, but manufacturing precision deteriorates due to increased quantization error

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoidquantization precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent dynamically changes quantization parameters based on signal energy and masking conditions. The quantization step size is adjusted according to the local signal characteristics, applying coarser quantization to low-energy masked channels and finer quantization to high-energy channels, thereby optimizing the trade-off between bandwidth efficiency and reconstruction accuracy.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If fine quantization is applied to all channels, then perceptual quality is maintained, but bandwidth consumption increases due to unnecessary precision for masked channels

Engineering Contradiction:
Improveperceptual qualityVSAvoidbandwidth consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies different quantization precision to different channels based on their perceptual importance. Channels that are masked by higher-energy signals receive coarser quantization since their contribution to perceptual quality is minimal, while unmasked high-energy channels receive finer quantization to maintain overall perceptual quality, thereby reducing total bandwidth consumption.

Inventive Principle:
Principle #3Local quality

4Loss of energy

If energy-dependent quantization is implemented, then bandwidth efficiency improves, but device complexity increases due to additional energy calculation and rule selection logic

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoidquantization system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent calculates signal energy and determines appropriate quantization rules in advance during the encoding process. By pre-computing energy levels and selecting quantization parameters before actual quantization occurs, the system prepares optimization strategies ahead of time, reducing the computational burden during real-time processing while maintaining bandwidth efficiency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8054981B2Energy dependent quantization for efficient coding of spatial audio parameters
Publication Date: 2011.11.08 DOLBY INTERNATIONAL AB
  • US8054981B2 patent drawing
  • US8054981B2 patent drawing
  • US8054981B2 patent drawing

AI summary

Parameters being a measure for a characteristic of a channel or of a pair of channels, wherein the parameter is a measure for a characteristic of the channel or of the pair of channels with respect to another channel of a multi-channel signal can be quantized more efficiently using a quantization rule that is generated based on a relation of an energy measure of the channel or the pair of channels and an energy measure of the multi-channel signal. With generation of the quantization rule taking into account a psycho acoustic approach, the size of an encoded representation of the multi-channel signal can be decreased by coarser quantization without significantly disturbing the perceptual quality of the multi-channel signal when reconstructed from the encoded representation.