fft.h File Reference

Fast Fourier Transform object. More...

#include <fftw3.h>

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Defines
#define	FFTW_TYPE   double
	fft data type
Typedefs
typedef FFTW_TYPE	fft_data_t
	fft data type
typedef struct _aubio_fft_t	aubio_fft_t
	FFT object.
typedef struct _aubio_mfft_t	aubio_mfft_t
	FFT object (using cvec)
Functions
aubio_fft_t *	new_aubio_fft (uint_t size)
	create new FFT computation object
void	del_aubio_fft (aubio_fft_t *s)
	delete FFT object
void	aubio_fft_do (const aubio_fft_t *s, const smpl_t *data, fft_data_t *spectrum, const uint_t size)
	compute forward FFT
void	aubio_fft_rdo (const aubio_fft_t *s, const fft_data_t *spectrum, smpl_t *data, const uint_t size)
	compute backward (inverse) FFT
void	aubio_fft_getnorm (smpl_t *norm, fft_data_t *spectrum, uint_t size)
	compute norm vector from input spectrum
void	aubio_fft_getphas (smpl_t *phase, fft_data_t *spectrum, uint_t size)
	compute phase vector from input spectrum
aubio_mfft_t *	new_aubio_mfft (uint_t winsize, uint_t channels)
	create new FFT computation object
void	aubio_mfft_do (aubio_mfft_t *fft, fvec_t *in, cvec_t *fftgrain)
	compute forward FFT
void	aubio_mfft_rdo (aubio_mfft_t *fft, cvec_t *fftgrain, fvec_t *out)
	compute backward (inverse) FFT
void	del_aubio_mfft (aubio_mfft_t *fft)
	delete FFT object

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Detailed Description

Fast Fourier Transform object.

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Typedef Documentation

typedef struct _aubio_fft_t aubio_fft_t

FFT object.

This object computes forward and backward FFTs, using the complex type to store the results. The phase vocoder or aubio_mfft_t objects should be preferred to using directly aubio_fft_t. The FFT are computed using FFTW3 (although support for another library could be added).

typedef struct _aubio_mfft_t aubio_mfft_t

FFT object (using cvec)

This object works similarly as aubio_fft_t, except the spectral data is stored in a cvec_t as two vectors, magnitude and phase.

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Function Documentation

void aubio_fft_do	(	const aubio_fft_t *	s,
		const smpl_t *	data,
		fft_data_t *	spectrum,
		const uint_t	size
	)

compute forward FFT

Parameters:

s	fft object as returned by new_aubio_fft
data	input signal
spectrum	output spectrum
size	length of the input vector

void aubio_fft_getnorm	(	smpl_t *	norm,
		fft_data_t *	spectrum,
		uint_t	size
	)

compute norm vector from input spectrum

Parameters:

norm	magnitude vector output
spectrum	spectral data input
size	size of the vectors

void aubio_fft_getphas	(	smpl_t *	phase,
		fft_data_t *	spectrum,
		uint_t	size
	)

compute phase vector from input spectrum

Parameters:

phase	phase vector output
spectrum	spectral data input
size	size of the vectors

void aubio_fft_rdo	(	const aubio_fft_t *	s,
		const fft_data_t *	spectrum,
		smpl_t *	data,
		const uint_t	size
	)

compute backward (inverse) FFT

Parameters:

s	fft object as returned by new_aubio_fft
spectrum	input spectrum
data	output signal
size	length of the input vector

void aubio_mfft_do	(	aubio_mfft_t *	fft,
		fvec_t *	in,
		cvec_t *	fftgrain
	)

compute forward FFT

Parameters:

fft	fft object as returned by new_aubio_mfft
in	input signal
fftgrain	output spectrum

void aubio_mfft_rdo	(	aubio_mfft_t *	fft,
		cvec_t *	fftgrain,
		fvec_t *	out
	)

compute backward (inverse) FFT

Parameters:

fft	fft object as returned by new_aubio_mfft
fftgrain	input spectrum (cvec)
out	output signal

void del_aubio_fft

(

aubio_fft_t *

s

)

delete FFT object

Parameters:

s	fft object as returned by new_aubio_fft

void del_aubio_mfft

(

aubio_mfft_t *

fft

)

delete FFT object

Parameters:

fft	fft object as returned by new_aubio_mfft

aubio_fft_t* new_aubio_fft

(

uint_t

size

)

create new FFT computation object

Parameters:

size	length of the FFT

aubio_mfft_t* new_aubio_mfft	(	uint_t	winsize,
		uint_t	channels
	)

create new FFT computation object

Parameters:

winsize	length of the FFT
channels	number of channels