LV::DFT Class Reference

Computes a Discrete Fourier Transform. More...

#include <libvisual/lv_fourier.h>

Public Member Functions
	DFT (unsigned int samples_out, unsigned int samples_in)
	Creates a DFT object used to calculate amplitude spectrums over audio data. More...
	DFT (DFT const &)=delete
	DFT (DFT &&rhs)
	Move constructor.
	~DFT ()
	Destructor.
DFT &	operator= (DFT const &)=delete
DFT &	operator= (DFT &&rhs)
	Move assignment operator.
unsigned int	get_spectrum_size () const
	Returns the output size of the DFT. More...
void	perform (float *output, float const *input)
	Performs a DFT over a set of input samples. More...

Static Public Member Functions
static void	log_scale (float *output, float const *input, unsigned int size)
	Logarithmically scales an amplitude spectrum. More...
static void	log_scale_standard (float *output, float const *input, unsigned int size)
static void	log_scale_custom (float *output, float const *input, unsigned int size, float log_scale_divisor)

Detailed Description

Computes a Discrete Fourier Transform.

Definition at line 41 of file lv_fourier.h.

Constructor & Destructor Documentation

LV::DFT::DFT	(	unsigned int	samples_out,
		unsigned int	samples_in
	)

Creates a DFT object used to calculate amplitude spectrums over audio data.

Note

For optimal performance, use a power-of-2 spectrum size. The current implementation does not use the Fast Fourier Transform for non powers of 2.

If samples_in is smaller than 2 * samples_out, the input will be padded with zeroes.

Parameters

samples_in	The number of samples provided to every call to DFT::perform() as input.
samples_out	Size of output spectrum (number of output samples).

Definition at line 203 of file lv_fourier.cpp.

Member Function Documentation

unsigned int LV::DFT::get_spectrum_size

(

)

const

Returns the output size of the DFT.

Returns

Output size

void LV::DFT::log_scale ( float *  output, float const *  input, unsigned int  size  )

static

Logarithmically scales an amplitude spectrum.

Note

Scaled values are guaranteed to be in [0.0, 1.0].

Parameters

output	Array of output samples
input	Array of input samples with values in [0.0, 1.0]
size	Array size.

Definition at line 245 of file lv_fourier.cpp.

void LV::DFT::perform	(	float *	output,
		float const *	input
	)

Performs a DFT over a set of input samples.

Parameters

output	Array of output samples
input	Array of input samples with values in [-1.0, 1.0]

Definition at line 226 of file lv_fourier.cpp.

Referenced by LV::Audio::get_spectrum_for_sample().

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The documentation for this class was generated from the following files:

• lv_fourier.h
• lv_fourier.cpp