Dynamic Analysis Window Selection for Bandwidth Extension
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Solution Overview
Problem
Existing audio codecs face challenges in maintaining optimal perceptual audio quality due to the use of predetermined analysis windows, which can lead to sub-optimal quality for individual audio signals and increased computational complexity, especially in bandwidth extension scenarios.
Innovation Solution
A method that analyzes audio signals to determine the optimal analysis window for bandwidth extension, using a signal analyzer to select the best window from a plurality of options based on comparison parameters, thereby minimizing quality reduction and improving perceptual quality with reduced computational efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a predetermined analysis window is used for bandwidth extension, then device complexity is reduced, but perceptual audio quality deteriorates
Solution Approach 1:
The patent implements dynamic selection of analysis window characteristics based on signal properties. The system adapts the analysis window parameters (such as window length and shape) according to the detected signal characteristics, transitioning from fixed predetermined windows to dynamically adjusted windows that optimize both quality and computational efficiency for different signal types.
Solution Approach 2:
The patent changes the parameters of the analysis window based on signal characteristics. By detecting properties of the input signal and adjusting window parameters accordingly, the system achieves optimal perceptual quality without requiring exhaustive search through all possible window configurations, thus balancing quality improvement with computational constraints.
2Manufacturing precision
If signal-dependent window selection is implemented, then perceptual audio quality is improved, but device complexity increases
Solution Approach 1:
The patent applies partial signal analysis to determine window characteristics rather than performing complete exhaustive analysis. By analyzing only the most relevant signal properties needed for window selection, the system achieves sufficient quality improvement without the computational burden of full signal characterization, implementing a balanced level of analysis effort.
Solution Approach 2:
The patent applies different analysis window characteristics to different portions of the signal based on local signal properties. Rather than using a single global window configuration, the system adapts window parameters to match local signal characteristics in different time-frequency regions, improving overall quality while keeping computational complexity manageable through localized adaptation.
3Adaptability or versatility
If multiple analysis windows are evaluated, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary evaluation of multiple analysis window options based on signal characteristics before final selection. By pre-assessing which window types are most suitable based on detected signal properties, the system narrows down the selection space early in the processing chain, maintaining high adaptability while reducing the computational burden of evaluating all possible window configurations in detail.
Data Source
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AI summary
A bandwidth extension encoder for encoding an audio signal comprises a signal analyzer, a core encoder and a parameter calculator. The audio signal comprises a low frequency signal comprising a core frequency band and a high frequency signal comprising an upper frequency band. The signal analyzer is configured for analyzing the audio signal, the audio signal having a block of audio samples, the block having a specified length in time. The signal analyzer is furthermore configured for determining from a plurality of analysis windows an analysis window to be used for performing a bandwidth extension in a bandwidth extension decoder. The core encoder is configured for encoding the low frequency signal to obtain an encoded or frequency signal. The parameter calculator is configured for calculating bandwidth extension parameters from the high frequency signal.