MPEG-SAOC Decoder Common Inter-Object Correlation

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Solution Overview

Problem

MPEG Spatial Audio Object Coding (SAOC) systems face challenges in achieving a good trade-off between audio quality and bitrate requirements, particularly due to the high bitrate demand for encoding inter-object-correlation values needed for a good hearing impression, especially when many audio objects exhibit significant correlations.

Innovation Solution

The system employs a common inter-object-correlation bitstream parameter value to encode correlations between multiple audio objects, reducing the bitrate requirement while maintaining a good hearing impression by setting inter-object-correlation values for related objects to a common value and zero for unrelated objects, and using a bitstream signaling parameter to differentiate between related and unrelated objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If individual inter-object-correlation bitstream parameter values are encoded for each pair of audio objects, then the hearing impression quality is improved, but the bitrate demand increases significantly

Engineering Contradiction:
Improvehearing impression qualityVSAvoidbitrate demand
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent merges multiple individual inter-object-correlation parameters into a single common inter-object-correlation bitstream parameter value that applies to all pairs of audio objects. This consolidation reduces the bitrate demand significantly while maintaining acceptable hearing impression quality, resolving the contradiction between precision and quantity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the parameter representation from multiple individual inter-object-correlation values to a single common parameter value. This parameter transformation allows the system to achieve comparable auditory quality with substantially reduced bitrate requirements by encoding one common value instead of multiple individual values.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If a common inter-object-correlation bitstream parameter value is used for all audio object pairs, then the bitrate demand is reduced, but the hearing impression quality may deteriorate

Engineering Contradiction:
Improvebitrate demandVSAvoidhearing impression quality
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent transforms the parameter structure from multiple individual values to a single common value, achieving bitrate reduction while maintaining acceptable quality through this parameter simplification approach.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By combining all inter-object-correlation parameters into one common parameter, the system achieves efficient bitrate usage while the merged parameter still captures the essential correlation characteristics needed for good hearing impression.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If inter-object-correlation values are encoded for many pairs of audio objects with significant correlations, then the audio quality is improved, but the complexity of the encoding system increases

Engineering Contradiction:
Improveaudio qualityVSAvoidencoding system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the complexity of handling multiple individual inter-object-correlation parameters into a single common parameter management approach, significantly simplifying the encoding system while maintaining audio quality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By changing from multiple individual parameters to one common parameter, the system reduces encoding complexity while preserving the essential correlation information needed for good audio quality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3093843B1MPEG-SAOC audio signal decoder, MPEG-SAOC audio signal encoder, method for providing an upmix signal representation using MPEG-SAOC decoding, method for providing a downmix signal representation using MPEG-SAOC decoding, and computer program using a time/frequency-dependent common inter-object-correlation parameter value
Publication Date: 2020.12.02 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3093843B1 patent drawingFigure 1
  • EP3093843B1 patent drawingFigure 2
  • EP3093843B1 patent drawingFigure 3

AI summary

An audio signal decoder for providing an upmix signal representation on the basis of a downmix signal representation and an object-related parametric information and in dependence on a rendering information comprises an object parameter determinator. The object parameter determinator is configured to obtain inter-object-correlation values for a plurality of pairs of audio objects. The object parameter determinator is configured to evaluate a bitstream signaling parameter in order to decide whether to evaluate individual inter-object-correlation bitstream parameter values to obtain inter-object-correlation values for a plurality of pairs of related audio objects, or to obtain inter-object-correlation values for a plurality of pairs of related audio objects using a common inter-object-correlation bitstream parameter value. The audio signal decoder also comprises a signal processor configured to obtain the upmix signal representation on the basis of the downmix signal representation and using the inter-object-correlation values for a plurality of pairs of related objects and the rendering information.