Audio Decoder Non-Harmonic Bandwidth Extension Mode

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Solution Overview

Problem

The existing audio decoding technologies, such as the Unified Speech and Audio Coding (USAC) standard, face challenges in managing computational complexity and memory consumption, particularly when implementing the harmonic bandwidth extension (HBE) mode, which is resource-intensive and not suitable for low-computational devices.

Innovation Solution

The solution involves decoding audio signals using a non-harmonic bandwidth extension mode even when the encoded signal indicates a harmonic bandwidth extension mode, thereby reducing computational complexity and memory requirements, while maintaining backward compatibility and improving audio quality by reusing harmonic bandwidth extension mode data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the harmonic bandwidth extension (HBE) mode is implemented in the decoder, then the perceptual audio quality is improved, but the computational complexity and memory consumption increase significantly

Engineering Contradiction:

Improveperceptual audio qualityVSAvoidcomputational complexity and memory consumption

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the operational parameters of the bandwidth extension process by switching from harmonic bandwidth extension (HBE) to non-harmonic bandwidth extension (NBWE). This parameter change allows the system to maintain acceptable audio quality while significantly reducing computational complexity and memory consumption, making the decoder suitable for low-resource devices.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a simpler, less resource-intensive NBWE approach instead of the complex HBE process. This 'cheaper' alternative consumes fewer computational resources and memory, enabling deployment on devices with limited capabilities while still providing functional bandwidth extension.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If the HBE tool is used to avoid auditory roughness, then the audio quality is improved, but the processing power and memory requirements increase

Engineering Contradiction:

Improveaudio qualityVSAvoidprocessing power and memory requirements

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

The patent changes the operational parameters by switching from HBE to NBWE mode. This parameter change reduces the processing power and memory requirements while maintaining functional bandwidth extension capabilities, making the system suitable for low-power devices.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes the computationally intensive components of the HBE process (phase vocoders, complex filter states, and delay lines) while retaining the essential bandwidth extension functionality through the simpler NBWE approach. This extraction eliminates unnecessary computational overhead.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the decoder implements HBE processing to meet USAC standard requirements, then the standard compliance is achieved, but the memory consumption increases by at least 15 kWords per audio channel

Engineering Contradiction:

Improvestandard complianceVSAvoidmemory consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the implementation parameter by using NBWE instead of HBE, thereby reducing memory consumption from at least 15 kWords per channel to a significantly lower amount, while still providing functional bandwidth extension that meets the essential requirements of the USAC standard.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a memory-efficient NBWE implementation that consumes far less memory than the HBE requirement of 15 kWords per channel. This lighter-weight approach provides sufficient functionality for most applications without the heavy memory burden.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS10332536B2Apparatus and method for decoding an encoded audio signal with low computational resources

Publication Date: 2019.06.25 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An apparatus for decoding an encoded audio signal including bandwidth extension control data indicating either a first harmonic bandwidth extension mode or a second non-harmonic bandwidth extension mode, includes: an input interface for receiving the encoded audio signal including the bandwidth extension control data indicating either the first harmonic bandwidth extension mode or the second non-harmonic bandwidth extension mode; a processor for decoding the audio signal using the second non-harmonic bandwidth extension mode; and a controller for controlling the processor to decode the audio signal using the second non-harmonic bandwidth extension mode, even when the bandwidth extension control data indicates the first harmonic bandwidth extension mode for the encoded signal.