Bandwidth Extension Parameter Generator for Audio Signals
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Solution Overview
Problem
Existing bandwidth extension methods for sound signals, such as the copy-up and harmonic methods, face challenges in maintaining harmonic relations and suffer from high complexity, delay, and memory requirements, which affect sound quality and processing efficiency.
Innovation Solution
A new bandwidth extension method that includes a derivation unit for generating a high-band signal and a calculation unit for determining tone and floor parameters, allowing for efficient encoding and decoding of sound signals with reduced complexity and delay by selectively extending tone and floor components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the copy-up method is used to generate high-frequency spectrum by copying low-frequency spectrum, then the processing complexity is reduced, but the harmonic relation between spectra cannot be accurately maintained, degrading sound quality
Solution Approach 1:
The patent segments the spectrum extension process into two distinct components: tone components (harmonic elements) and floor components (noise elements). By separating these components and applying different extension strategies to each, the method achieves accurate harmonic relations for tone components while keeping the overall processing relatively simple. The tone components are extended using harmonic relationships from the low-frequency band, while floor components are extended using spectral copying, thus resolving the contradiction between simplicity and harmonic accuracy.
2Manufacturing precision
If the harmonic method is used to stretch and cut low-frequency spectrum to generate high-frequency spectrum, then the harmonic relation is maintained, but the processing delay increases and memory requirements increase due to complicated processing
Solution Approach 1:
The patent divides the spectrum into tone components and floor components, applying different extension methods to each. For tone components, it uses a simplified harmonic extension approach that maintains harmonic relations without requiring the complex time-stretching and resampling operations of the traditional harmonic method. For floor components, it uses spectral copying which is computationally efficient. This segmentation allows the patent to maintain harmonic accuracy while significantly reducing processing delay and memory requirements.
Solution Approach 2:
The patent applies different quality levels of extension methods to different spectral components based on their characteristics. Tone components, which require accurate harmonic relations, receive sophisticated harmonic extension treatment. Floor components, which are noise-like and less sensitive to harmonic accuracy, receive simpler spectral copying treatment. This local differentiation of processing quality allows the system to maintain overall sound quality while reducing computational complexity and delay.
3Manufacturing precision
If the harmonic method is used for bandwidth extension, then the harmonic relation is maintained, but the memory usage increases due to complicated processing
Solution Approach 1:
By segmenting the spectrum into tone and floor components, the patent can apply memory-efficient processing to each. The tone component extension uses minimal memory by directly computing harmonic relationships from low-frequency tone parameters. The floor component extension uses spectral copying which requires minimal additional memory buffers. This segmentation eliminates the need for large memory allocations required by the traditional harmonic method's time-stretching operations.
Data Source
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AI summary
A bandwidth extension parameter generation device (306) includes: a derivation unit (303) which derives a high-band signal representing a high-band portion of an input sound signal; and a calculation unit (304) which calculates a tone parameter and a floor parameter, the tone parameter indicating a magnitude of energy of a tone component of the high-band signal, the floor parameter indicating a magnitude of energy of a floor component obtained by subtracting the tone component from the high-band signal.