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I'm trying to process audio data. I'm working with Java. I've extracted the audio data to an array. Now I should pass N data samples to a function that calculates the Discrete Fourier Transform (or Fast Fourier Transform, which is more efficient). I've read documentation but I'm getting more and more confused. What I'm trying to calculate is the magnitude spectrum (|X(k)|). Can anyone help me? Thanks
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The "Fast Fourier Transform" (FFT) is an important measurement method in the science of audio and acoustics measurement. It converts a signal into individual spectral components and thereby provides frequency information about the signal.
With MP3, the sound samples are transformed using methods that involve Fourier Series Transformations.
In the processing of audio signals (although it can be used for radio waves, light waves, seismic waves, and even images), Fourier analysis can isolate individual components of a continuous complex waveform, and concentrate them for easier detection and/or removal.
Richard G. Baldwin has a number of very good articles on Fast Fourier Transform algorithms in Java on the Developer.com website. In particular, the following articles should prove to be useful:
Fun with Java, Understanding the Fast Fourier Transform (FFT) Algorithm http://www.developer.com/java/other/article.php/3457251/Fun-with-Java-Understanding-the-Fast-Fourier-Transform-FFT-Algorithm.htm
Spectrum Analysis using Java, Sampling Frequency, Folding Frequency, and the FFT Algorithm http://www.developer.com/java/other/article.php/3380031/Spectrum-Analysis-using-Java-Sampling-Frequency-Folding-Frequency-and-the-FFT-Algorithm.htm
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If you only want Magnitude Spectrum of audio, go for jAudio API.
It provides class for calculating MS.
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