Frequency-Domain Loudness Processing for Variable Audio Blocks

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Solution Overview

Problem

Perceptual audio coders with varying block sizes complicate the efficient determination and modification of perceived loudness in audio signals, as existing methods struggle to maintain constant frequency and temporal resolution, leading to complexities in sound quality for transient audio signals.

Innovation Solution

The method involves combining frequency domain data from multiple blocks of varying sizes to form a longest block size, interpolating gain information, and applying loudness modifications to maintain consistent loudness processing, using techniques like interleaving or replicating data to create a constant block size for processing, thereby ensuring accurate loudness determination and modification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If perceptual audio coders use varying block sizes to improve sound quality for transient audio signals, then adaptability is improved, but device complexity increases and measurement precision deteriorates

Engineering Contradiction:
Improveadaptability to transient audio signalsVSAvoidcomplexity of loudness processing
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of block size from variable to fixed (longest block size) for loudness processing. By converting varying block sizes to a uniform longest block size, the system maintains adaptability for different audio content while simplifying the loudness processing complexity and ensuring consistent measurement precision across all blocks.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments audio data into multiple blocks of varying sizes based on content characteristics, then further segments or pads these blocks to a uniform longest block size for loudness processing. This segmentation approach allows the system to handle transient signals with appropriate block sizes while maintaining consistent processing parameters for accurate loudness measurement.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If perceptual audio coders use varying block sizes, then adaptability is improved, but measurement precision of loudness determination deteriorates

Engineering Contradiction:
Improveadaptability to different audio contentVSAvoidprecision of loudness determination
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent changes the processing block size parameter from variable to fixed (longest block size) to ensure consistent frequency and temporal resolution for loudness measurement. This parameter change maintains adaptability through selective block size selection while guaranteeing measurement precision through uniform processing dimensions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates equipotential conditions for loudness measurement by ensuring all blocks are processed at the same longest block size. This eliminates variations in measurement conditions that would otherwise affect precision, while still allowing adaptability in the initial block selection based on audio content characteristics.

Inventive Principle:
Principle #12Equipotentiality

3Adaptability or versatility

If loudness processing is performed on varying block sizes, then adaptability is improved, but productivity decreases due to complex operations

Engineering Contradiction:
Improvehandling of different block sizesVSAvoidefficiency of loudness processing
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent changes the block size parameter from variable to fixed (longest block size) for loudness processing operations. This parameter standardization improves productivity by enabling efficient, uniform processing algorithms while maintaining adaptability through the initial selection of appropriate block sizes based on audio content.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary action by converting all varying blocks to the longest block size before loudness processing. This preprocessing step, though requiring additional operations, enables subsequent efficient and standardized loudness calculations, improving overall productivity by avoiding repeated complex adaptations during processing.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2374211B1Audio signal loudness determination and modification in the frequency domain
Publication Date: 2012.04.04 DOLBY LABORATORIES LICENSING CORP
  • EP2374211B1 patent drawingFigure 1
  • EP2374211B1 patent drawingFigure 2
  • EP2374211B1 patent drawingFigure 3

AI summary

Methods of, apparatuses for, and computer readable media having instructions thereon that when executed cause carrying out methods of determining and modifying the perceived loudness of a frequency domain audio signal where the frequency resolution, and corresponding temporal coverage of the frequency domain information is not constant. The frequency (and thus temporal) resolution of the perceived loudness processing is maintained constant at the longest block size. One method includes a block combiner and a loudness modification interpolator.