Spectral Domain Audio Patching Without Blocking Artifacts

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Solution Overview

Problem

Existing bandwidth extension methods, such as spectral band replication (SBR), lack flexibility and adaptability in switching between different patching algorithms, leading to blocking artifacts and increased complexity due to domain transitions.

Innovation Solution

Implementing a system that allows switching between multiple spectral domain patching algorithms, including harmonic transposition, non-harmonic copying-up SBR, and non-linear distortion, within the spectral domain to generate a modified spectral representation, thereby eliminating the need for domain transitions and reducing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple patching algorithms are switched between in different domains, then adaptability is improved, but device complexity increases due to domain transitions

Engineering Contradiction:

Improvealgorithm switching flexibilityVSAvoidprocessing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple patching algorithms into a unified spectral domain framework, eliminating the need for domain transitions. Different patching strategies (harmonic transposition, non-harmonic copying, non-linear distortion) are integrated and switched within the same spectral domain, reducing complexity while maintaining adaptability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The spectral domain patch generator is designed as a universal processing unit that can perform multiple patching operations (harmonic transposition, non-harmonic copying-up SBR, non-linear distortion) within a single domain, eliminating the need for separate domain-specific processing paths and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If domain transitions are performed for patching operations, then algorithm flexibility is improved, but blocking artifacts increase

Engineering Contradiction:

Improvepatching algorithm diversityVSAvoidblocking artifacts

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent combines multiple patching algorithms into a single spectral domain processing path, eliminating domain transitions that cause blocking artifacts. The unified approach ensures smooth processing without the artifacts introduced by switching between time and frequency domains.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If spectral band replication is performed with high processing complexity, then manufacturing precision is improved, but productivity decreases

Engineering Contradiction:

Improveperceptual qualityVSAvoidprocessing efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent extracts and processes only the essential spectral components needed for bandwidth extension, rather than performing exhaustive processing. By working directly in the spectral domain and selectively applying patching operations only where needed, the system maintains high perceptual quality while improving processing efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The spectral conversion is performed preliminarily before patching operations, organizing the signal in a domain where all subsequent processing can be efficiently conducted without further domain transitions. This preliminary spectral analysis enables faster processing while maintaining quality.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUSRE50767E1Apparatus and method for generating a synthesis audio signal and for encoding an audio signal

Publication Date: 2026.01.27 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An apparatus for generating a synthesis audio signal using a patching control signal has a first converter, a spectral domain patch generator, a high frequency reconstruction manipulator and a combiner. The first converter is configured for converting a time portion of an audio signal into a spectral representation. The spectral domain patch generator is configured for performing a plurality of different spectral domain patching algorithms, wherein each patching algorithm generates a modified spectral representation having spectral components in an upper frequency band derived from corresponding spectral components in a core frequency band of the audio signal. The spectral domain patch generator is furthermore configured to select a first spectral domain patching algorithm from the plurality of patching algorithms for a first time portion and a second spectral domain patching algorithm from the plurality of patching algorithm for a second different time portion in accordance with the patching control signal to obtain the modified spectral representation.