Audio Frequency Band Detection via Spectral Parameter Index
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Solution Overview
Problem
Existing methods for detecting the frequency band of audio signals coded using linear predictive coding techniques are complex and resource-intensive, particularly when they require complete decoding and application of FFT or MDCT transforms, which is undesirable in applications where computational resources are limited.
Innovation Solution
A method that determines the presence of a predetermined frequency band by decoding and analyzing spectral parameters within specific blocks of an audio signal, calculating a criterion based on the index of the first spectral parameter closest to a threshold frequency, and deciding whether the frequency band is detected, thereby reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete decoding and FFT or MDCT transforms are applied to detect frequency band, then detection accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent extracts only the necessary spectral parameters (LPC coefficients) from the coded audio signal that are sufficient for frequency band detection, rather than performing complete decoding and applying complex transforms like FFT or MDCT. This extraction approach maintains detection accuracy while significantly reducing computational complexity by working directly with the encoded spectral information.
Solution Approach 2:
The detection process is segmented into analyzing individual spectral parameters (LPC coefficients) separately rather than processing the entire decoded signal through complex transforms. By segmenting the analysis to focus only on relevant spectral characteristics, the patent achieves accurate frequency band detection with reduced computational burden.
2Reliability
If complete decoding is performed for frequency band detection, then detection reliability is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary analysis on the spectral parameters that are already available in the coded signal structure (LPC coefficients), rather than waiting for complete decoding. This preliminary action on pre-existing spectral data maintains detection reliability while avoiding the time-consuming complete decoding and transform processes.
Solution Approach 2:
The patent extracts frequency band information directly from the coded spectral parameters without requiring complete signal reconstruction. By taking out only the necessary spectral characteristics from the coded data, the method achieves reliable detection with significantly reduced processing time.
Data Source
AI summary
A method is provided for detecting a predetermined frequency band in an audio data signal which has previously been coded according to a succession of data blocks, among which at least certain blocks contain respectively at least one set of spectral parameters representing a linear prediction filter. Such a method of detection implements, for a current block among the at least certain blocks and for which at least a plurality of spectral parameters of the set have been previously decoded, acts of: determining, among the plurality of previously decoded spectral parameters, the index of the first spectral parameter closest to a threshold frequency; calculating at least one criterion on the basis of the determined index; and deciding whether the predetermined frequency band is detected in the current block, as a function of the criterion calculated.