Executes FFT using audio data privded by write() and/or an inverse FFT where the samples are made available via readBytes(). 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)

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 ()

int	available () override
	Data available for reverse fft.

int	availableForWrite () override
	We try to fill the buffer at once.

bool	begin () override
	starts the processing

bool	begin (AudioFFTConfig info)
	starts the processing

void	clearBins ()
	clears the fft data

virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.

AudioFFTConfig &	config ()
	Provides the actual configuration.

AudioFFTConfig	defaultConfig (RxTxMode mode=TX_MODE)
	Provides the default configuration.

FFTDriver *	driver ()

void	end () override
	Release the allocated memory.

virtual void	flush () override

float	frequency (int bin)
	Determines the frequency of the indicated bin.

int	frequencyToBin (int freq)
	Determine the bin number from the frequency.

bool	fromMEL (float *values, int n_bins, float min_freq=0.0f, float max_freq=0.0f)
	Convert MEL spectrum back to linear frequency spectrum.

bool	getBin (int pos, FFTBin &bin)
	gets the value of a bin

bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.

int	length ()
	The number of samples.

float	magnitude (int bin)

float	magnitudeFast (int bin)

float *	magnitudes ()

float *	magnitudesFast ()

	operator bool () override

float	phase (int bin)
	calculates the phase

size_t	readBytes (uint8_t *data, size_t len) override
	Provides the result of a reverse FFT.

virtual size_t	readSilence (uint8_t *buffer, size_t length)
	Source to generate silence: just sets the buffer to 0.

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 ()

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	setWriteBufferSize (int size)

int	size ()
	The number of bins used by the FFT which are relevant for the result.

float *	toMEL (int n_bins, float min_freq=0.0f, float max_freq=0.0f)
	Convert the FFT result to MEL spectrum.

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)
	Writes len bytes of silence (=0).

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)

virtual int	not_supported (int out, const char *msg="")

void	notifyAudioChange (AudioInfo info)

template<typename T >
void	processSamples (const void *data, size_t count)

void	refillReadBuffer ()

void	rfft ()
	reverse fft

void	rfftWriteData (BaseBuffer< uint8_t > &data)
	write reverse fft result to buffer to make it available for readBytes

template<typename T >
T	windowedSample (T sample, int pos)

template<typename T >
void	writeIFFT (float *data, int len)

bool	writeStrideBuffer (uint8_t *buffer, size_t len)

Protected Attributes
int	_timeout = 10

int	bins = 0

AudioFFTConfig	cfg

int	current_pos = 0

bool	has_rfft_data = false

AudioInfo	info

bool	is_notify_active = true

Vector< float >	l_magnitudes {0}

Vector< float >	mel_bins {0}

Vector< AudioInfoSupport * >	notify_vector

FFTDriver *	p_driver = nullptr

FFTInverseOverlapAdder	rfft_add {0}

RingBuffer< uint8_t >	rfft_data {0}

Vector< float >	step_data {0}

SingleBuffer< uint8_t >	stride_buffer {0}

unsigned long	timestamp = 0l

unsigned long	timestamp_begin = 0l

RingBuffer< uint8_t >	tmp_in {0}

RingBuffer< uint8_t >	tmp_out {0}

int	write_buffer_size = MAX_SINGLE_CHARS

Detailed Description

Executes FFT using audio data privded by write() and/or an inverse FFT where the samples are made available via readBytes(). The Driver which is passed in the constructor selects a specifc FFT implementation.

Author: Phil Schatzmann

Copyright: GPLv3

Constructor & Destructor Documentation

◆ AudioFFTBase()

AudioFFTBase ( FFTDriver * driver )

inline

Default Constructor. The len needs to be of the power of 2 (e.g. 512, 1024, 2048, 4096, 8192)

Member Function Documentation

◆ addNotifyAudioChange()

virtual void addNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

Adds target to be notified about audio changes.

Reimplemented in CodecNOP, EncodedAudioOutput, EncodedAudioStream, AACDecoderFDK, DecoderBasic, CodecChain, MP3DecoderHelix, MP3DecoderMAD, OggContainerDecoder, RTSPClient< TcpClient, UdpSocket >, Pipeline, and Pipeline::ModifyingStreamAdapter.

◆ audioInfo()

virtual AudioInfo audioInfo ( )

inlineoverridevirtualinherited

provides the actual input AudioInfo

Implements AudioInfoSupport.

Reimplemented in JupyterAudioT< T >, MozziStream, TimerCallbackAudioStream, EncodedAudioStream, PureDataStream, AdapterAudioOutputToAudioStream, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, and InputMerge< T >.

◆ audioInfoOut()

virtual AudioInfo audioInfoOut ( )

inlinevirtualinherited

provides the actual output AudioInfo: this is usually the same as audioInfo() unless we use a transforming stream

Reimplemented in PureDataStream, PWMAudioOutput, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, FormatConverterStream, Pipeline, ResampleStream, and ResampleStreamT< TInterpolator >.

◆ available()

int available ( )

inlineoverridevirtual

Data available for reverse fft.

Reimplemented from BaseStream.

◆ availableForWrite()

int availableForWrite ( )

inlineoverridevirtual

We try to fill the buffer at once.

Reimplemented from BaseStream.

◆ begin()

bool begin ( )

inlineoverridevirtual

starts the processing

Reimplemented from BaseStream.

◆ clearNotifyAudioChange()

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

◆ driver()

FFTDriver * driver ( )

inline

provides access to the FFTDriver which implements the basic FFT functionality

◆ end()

void end ( )

inlineoverridevirtual

Release the allocated memory.

Reimplemented from BaseStream.

◆ flush()

virtual void flush ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in ResampleStream, BufferedTaskStream, and BufferedStream.

◆ fromMEL()

bool fromMEL	(	float *	values,
		int	n_bins,
		float	min_freq = `0.0f`,
		float	max_freq = `0.0f`
	)

inline

Convert MEL spectrum back to linear frequency spectrum.

Parameters

values	Pointer to MEL spectrum values
n_bins	Number of MEL bins

Returns: bool Success status

◆ magnitude()

float magnitude ( int bin )

inline

Calculates the magnitude of the fft result to determine the max value (bin is 0 to size())

◆ magnitudes()

float * magnitudes ( )

inline

Provides the magnitudes as array of size size(). Please note that this method is allocating additinal memory!

◆ magnitudesFast()

float * magnitudesFast ( )

inline

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()

operator bool ( )

inlineoverridevirtual

Reimplemented from AudioStream.

◆ readBytes()

size_t readBytes	(	uint8_t *	data,
		size_t	len
	)

inlineoverridevirtual

Provides the result of a reverse FFT.

Reimplemented from AudioStream.

◆ removeNotifyAudioChange()

virtual bool removeNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

Removes a target in order not to be notified about audio changes.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

◆ resultTime()

unsigned long resultTime ( )

inline

time after the fft: time when the last result was provided - you can poll this to check if we have a new result

◆ setAudioInfo()

void setAudioInfo ( AudioInfo info )

inlineoverridevirtual

Notify change of audio information.

Reimplemented from AudioStream.

◆ write() [1/2]

size_t write	(	const uint8_t *	data,
		size_t	len
	)

inlineoverridevirtual

Provide the audio data as FFT input.

Reimplemented from AudioStream.

◆ write() [2/2]

virtual size_t write ( uint8_t ch )

inlineoverridevirtualinherited

Reimplemented in BufferedTaskStream, and BufferedStream.

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

src/AudioTools/AudioLibs/AudioFFT.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ AudioFFTBase()

Member Function Documentation

◆ addNotifyAudioChange()

◆ audioInfo()

◆ audioInfoOut()

◆ available()

◆ availableForWrite()

◆ begin()

◆ clearNotifyAudioChange()

◆ driver()

◆ end()

◆ flush()

◆ fromMEL()

◆ magnitude()

◆ magnitudes()

◆ magnitudesFast()

◆ operator bool()

◆ readBytes()

◆ removeNotifyAudioChange()

◆ resultTime()

◆ setAudioInfo()

◆ write() [1/2]

◆ write() [2/2]