Spatial Audio Transport Signal Conversion for Renderer Compatibility

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Solution Overview

Problem

Existing immersive audio codecs like IVAS struggle to ensure optimal audio quality when decoding and rendering spatial audio streams due to varying transport audio signal types, as not all external renderers support all possible transport audio signal types, leading to compatibility issues.

Innovation Solution

An apparatus and method to modify transport audio signals within spatial audio streams to match a target type, ensuring compatibility with systems requiring specific transport audio signal types, such as converting 'spaced' or 'mono' signals to 'cardioid' signals using spatial analyzers, encoders, decoders, and signal type converters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spatial audio streams are decoded and rendered to various output formats, then audio versatility and adaptability are improved, but audio quality and compatibility deteriorate due to varying transport audio signal types

Engineering Contradiction:
Improverendering flexibilityVSAvoidaudio quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary conversion process that transforms transport audio signals into a standardized format before rendering. This mediator component handles the signal type conversion, allowing the rendering system to maintain consistent quality expectations while supporting multiple input formats. The conversion layer acts as a buffer between the variable transport signals and the fixed rendering requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter state of transport audio signals by converting them from their original types (e.g., spaced, omnidirectional) to a target type (e.g., coincident cardioids). This parameter transformation enables the audio processing pipeline to operate on standardized signal characteristics, ensuring reliable quality across different rendering scenarios while maintaining versatility in accepting various input formats.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If transport audio signals are converted to match target types, then compatibility with rendering systems is improved, but device complexity increases

Engineering Contradiction:
Improverenderer compatibilityVSAvoidsignal processing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal conversion framework that handles multiple signal type transformations through a single standardized process. Rather than creating separate conversion paths for each signal type combination, the system uses a multi-functional conversion mechanism that can adapt to any input type and produce the required target type, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent performs signal type conversion as a preliminary step before the main rendering process. By standardizing the transport audio signals upfront, the system eliminates the need for complex conditional logic and multiple specialized processing paths later in the pipeline, thereby reducing device complexity while maintaining broad compatibility.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If spatial metadata is used to describe sound field parameters, then spatial audio quality is improved, but data transmission requirements increase

Engineering Contradiction:
Improvespatial audio qualityVSAvoiddata transmission
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential spatial parameters needed for accurate rendering from the full spatial metadata set. By selecting and transmitting only the critical parameters (such as direction, distance, and energy distribution) rather than complete spatial information, the system maintains high audio quality while reducing data transmission requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by transmitting a subset of spatial metadata parameters that are sufficient for achieving the desired spatial audio quality. Rather than transmitting all possible spatial parameters, the system identifies and transmits only the necessary portion, balancing quality requirements with data efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3757992B1Spatial audio representation and rendering
Publication Date: 2025.09.17 NOKIA TECHNOLOGIES OY
  • EP3757992B1 patent drawingFigure 1
  • EP3757992B1 patent drawingFigure 2
  • EP3757992B1 patent drawingFigure 3

AI summary

An apparatus comprising means configured to: obtain at least one audio stream, wherein the at least one audio stream comprises one or more transport audio signals, wherein the one or more transport audio signals is a defined type of transport audio signal; and convert the one or more transport audio signals to at least one or more further transport audio signals, the one or more further transport audio signals being a further defined type of transport audio signal.