spectral/fft.h File Reference

Fast Fourier Transform. More...

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Typedefs
typedef struct _aubio_fft_t	aubio_fft_t
	FFT object.
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 (aubio_fft_t *s, fvec_t *input, cvec_t *spectrum)
	compute forward FFT
void	aubio_fft_rdo (aubio_fft_t *s, cvec_t *spectrum, fvec_t *output)
	compute backward (inverse) FFT
void	aubio_fft_do_complex (aubio_fft_t *s, fvec_t *input, fvec_t *compspec)
	compute forward FFT
void	aubio_fft_rdo_complex (aubio_fft_t *s, fvec_t *compspec, fvec_t *output)
	compute backward (inverse) FFT from real/imag
void	aubio_fft_get_spectrum (fvec_t *compspec, cvec_t *spectrum)
	convert real/imag spectrum to norm/phas spectrum
void	aubio_fft_get_realimag (cvec_t *spectrum, fvec_t *compspec)
	convert real/imag spectrum to norm/phas spectrum
void	aubio_fft_get_phas (fvec_t *compspec, cvec_t *spectrum)
	compute phas spectrum from real/imag parts
void	aubio_fft_get_imag (cvec_t *spectrum, fvec_t *compspec)
	compute imaginary part from the norm/phas cvec
void	aubio_fft_get_norm (fvec_t *compspec, cvec_t *spectrum)
	compute norm component from real/imag parts
void	aubio_fft_get_real (cvec_t *spectrum, fvec_t *compspec)
	compute real part from norm/phas components

---

Detailed Description

Fast Fourier Transform.

Depending on how aubio was compiled, FFT are computed using one of:

• [Ooura](http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html)
• [FFTW3](http://www.fftw.org)
• [vDSP](https://developer.apple.com/library/mac/#documentation/Accelerate/Reference/vDSPRef/Reference/reference.html)

Definition in file fft.h.

---

Typedef Documentation

typedef struct _aubio_fft_t aubio_fft_t

FFT object.

This object computes forward and backward FFTs.

Definition at line 46 of file fft.h.

---

Function Documentation

void aubio_fft_do	(	aubio_fft_t *	s,
		fvec_t *	input,
		cvec_t *	spectrum
	)

compute forward FFT

Parameters:

s	fft object as returned by new_aubio_fft
input	input signal
spectrum	output spectrum

Examples:

src/spectral/test-fft.c.

void aubio_fft_do_complex	(	aubio_fft_t *	s,
		fvec_t *	input,
		fvec_t *	compspec
	)

compute forward FFT

Parameters:

s	fft object as returned by new_aubio_fft
input	real input signal
compspec	complex output fft real/imag

void aubio_fft_get_imag	(	cvec_t *	spectrum,
		fvec_t *	compspec
	)

compute imaginary part from the norm/phas cvec

Parameters:

spectrum	norm/phas input array
compspec	real/imag output fft array

void aubio_fft_get_norm	(	fvec_t *	compspec,
		cvec_t *	spectrum
	)

compute norm component from real/imag parts

Parameters:

compspec	real/imag input fft array
spectrum	cvec norm/phas output array

void aubio_fft_get_phas	(	fvec_t *	compspec,
		cvec_t *	spectrum
	)

compute phas spectrum from real/imag parts

Parameters:

compspec	real/imag input fft array
spectrum	cvec norm/phas output array

void aubio_fft_get_real	(	cvec_t *	spectrum,
		fvec_t *	compspec
	)

compute real part from norm/phas components

Parameters:

spectrum	norm/phas input array
compspec	real/imag output fft array

void aubio_fft_get_realimag	(	cvec_t *	spectrum,
		fvec_t *	compspec
	)

convert real/imag spectrum to norm/phas spectrum

Parameters:

compspec	real/imag input fft array
spectrum	cvec norm/phas output array

void aubio_fft_get_spectrum	(	fvec_t *	compspec,
		cvec_t *	spectrum
	)

convert real/imag spectrum to norm/phas spectrum

Parameters:

compspec	real/imag input fft array
spectrum	cvec norm/phas output array

void aubio_fft_rdo	(	aubio_fft_t *	s,
		cvec_t *	spectrum,
		fvec_t *	output
	)

compute backward (inverse) FFT

Parameters:

s	fft object as returned by new_aubio_fft
spectrum	input spectrum
output	output signal

Examples:

src/spectral/test-fft.c.

void aubio_fft_rdo_complex	(	aubio_fft_t *	s,
		fvec_t *	compspec,
		fvec_t *	output
	)

compute backward (inverse) FFT from real/imag

Parameters:

s	fft object as returned by new_aubio_fft
compspec	real/imag input fft array
output	real output array

void del_aubio_fft

(

aubio_fft_t *

s

)

delete FFT object

Parameters:

s	fft object as returned by new_aubio_fft

Examples:

src/spectral/test-fft.c.

aubio_fft_t* new_aubio_fft

(

uint_t

size

)

create new FFT computation object

Parameters:

size	length of the FFT

Examples:

src/spectral/test-fft.c.