AudioFFTBase Class Reference

Executes FFT using audio data. The Driver which is passed in the constructor selects a specifc FFT implementation. More...

#include <AudioFFT.h>

Inheritance diagram for AudioFFTBase:

Public Member Functions
	AudioFFTBase (FFTDriver *driver)
	Default Constructor. The len needs to be of the power of 2 (e.g. 512, 1024, 2048, 4096, 8192)
virtual void	addNotifyAudioChange (AudioInfoSupport &bi)
	Adds target to be notified about audio changes.
virtual AudioInfo	audioInfo () override
	provides the actual input AudioInfo
virtual AudioInfo	audioInfoOut ()
	provides the actual output AudioInfo: this is usually the same as audioInfo() unless we use a transforming stream
int	availableForWrite () override
	We try to fill the buffer at once.
bool	begin () override
	starts the processing
bool	begin (AudioFFTConfig info)
	starts the processing
virtual bool	begin (AudioInfo info)
virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.
AudioFFTConfig &	config ()
	Provides the actual configuration.
AudioFFTConfig	defaultConfig ()
	Provides the default configuration.
FFTDriver *	driver ()
	provides access to the FFTDriver which implements the basic FFT functionality
void	end () override
	Release the allocated memory.
virtual void	flush ()
float	frequency (int bin)
	Determines the frequency of the indicated bin.
bool	getBin (int pos, FFTBin &bin)
	gets the value of a bin
virtual bool	isDeletable ()
	If true we need to release the related memory in the destructor.
bool	isInverseFFT ()
	Returns true if we need to calculate the inverse FFT.
bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.
int	length ()
	The number of samples.
float	magnitude (int bin)
	Calculates the magnitude of the fft result to determine the max value (bin is 0 to size())
float	magnitudeFast (int bin)
float *	magnitudes ()
	Provides the magnitudes as array of size size(). Please note that this method is allocating additinal memory!
float *	magnitudesFast ()
	Provides the magnitudes w/o calling the square root function as array of size size(). Please note that this method is allocating additinal memory!
	operator bool ()
virtual bool	removeNotifyAudioChange (AudioInfoSupport &bi)
	Removes a target in order not to be notified about audio changes.
void	reset ()
	Just resets the current_pos e.g. to start a new cycle.
AudioFFTResult	result ()
	Determines the result values in the max magnitude bin.
template<int N>
void	resultArray (AudioFFTResult(&result)[N])
	Determines the N biggest result values.
unsigned long	resultTime ()
	time after the fft: time when the last result was provided - you can poll this to check if we have a new result
unsigned long	resultTimeBegin ()
	time before the fft
void	setAudioInfo (AudioInfo info) override
	Notify change of audio information.
bool	setBin (int idx, float real, float img)
	sets the value of a bin
bool	setBin (int pos, FFTBin &bin)
	sets the value of a bin
void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active)
void	setOutput (Print &out)
	Define final output for reverse ffft.
int	size ()
	The number of bins used by the FFT which are relevant for the result.
size_t	write (const uint8_t *data, size_t len) override
	Provide the audio data as FFT input.
virtual size_t	write (uint8_t ch) override
virtual void	writeSilence (size_t len)

Protected Member Functions
int	bytesPerSample ()
template<typename T >
void	fft ()
template<int N>
void	insertSorted (AudioFFTResult(&result)[N], AudioFFTResult tmp)
	make sure that we do not reuse already found results
bool	isPowerOfTwo (uint16_t x)
void	notifyAudioChange (AudioInfo info)
template<typename T >
void	processSamples (const void *data, size_t samples)
void	rfft ()
	reverse fft if necessary
template<typename T >
T	windowedSample (T sample)
void	writeStrideBuffer (uint8_t *buffer, size_t len)

Protected Attributes
int	_timeout = 10
int	bins = 0
AudioFFTConfig	cfg
int	current_pos = 0
bool	is_active = false
bool	is_notify_active = true
Vector< AudioInfoSupport * >	notify_vector
FFTDriver *	p_driver =nullptr
float *	p_magnitudes = nullptr
Print *	p_out = nullptr
float	rfft_max = 0
RingBuffer< uint8_t >	stride_buffer {0}
unsigned long	timestamp =0l
unsigned long	timestamp_begin =0l
SingleBuffer< uint8_t >	tmp {MAX_SINGLE_CHARS}
int	tmpPos = 0

Detailed Description

Executes FFT using audio data. The Driver which is passed in the constructor selects a specifc FFT implementation.

Author

Phil Schatzmann

Copyright

GPLv3

Member Function Documentation

writeSilence()

virtual void writeSilence ( size_t  len )

inlinevirtualinherited

Writes n 0 values (= silence)

Parameters

len

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

• src/AudioTools/AudioLibs/AudioFFT.h