AudioFFTBase Class Reference

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)
	~AudioFFTBase ()
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.
template<typename T >
T &	reference ()
	Provides the reference pointer.
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 ()
	Refill small read buffer (e.g. 8 bytes) to avoid single byte reads when calling read()
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)

~AudioFFTBase()

~AudioFFTBase ( )

inline

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() [1/2]

bool begin ( )

inlineoverridevirtual

starts the processing

Reimplemented from BaseStream.

begin() [2/2]

bool begin ( AudioFFTConfig  info )

inline

starts the processing

bytesPerSample()

int bytesPerSample ( )

inlineprotected

clearBins()

void clearBins ( )

inline

clears the fft data

clearNotifyAudioChange()

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

config()

AudioFFTConfig & config ( )

inline

Provides the actual configuration.

defaultConfig()

AudioFFTConfig defaultConfig ( RxTxMode  mode = TX_MODE )

inline

Provides the default configuration.

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.

fft()

template<typename T >

void fft ( )

inlineprotected

flush()

virtual void flush ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in PureDataStream, URLStreamBufferedT< T >, URLStreamBufferedT< ICYStream >, AudioStreamWrapper, ResampleStream, URLStream, BufferedTaskStream, I2SStream, MemoryStream, RingBufferStream, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, and BufferedStream.

frequency()

float frequency ( int  bin )

inline

Determines the frequency of the indicated bin.

frequencyToBin()

int frequencyToBin ( int  freq )

inline

Determine the bin number from the frequency.

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

getBin()

bool getBin ( int  pos, FFTBin &  bin  )

inline

gets the value of a bin

insertSorted()

template<int N>

void insertSorted ( AudioFFTResult(&)  result[N], AudioFFTResult  tmp  )

inlineprotected

make sure that we do not reuse already found results

isNotifyActive()

bool isNotifyActive ( )

inlineinherited

Checks if the automatic AudioInfo update is active.

isPowerOfTwo()

bool isPowerOfTwo ( uint16_t  x )

inlineprotected

length()

int length ( )

inline

The number of samples.

magnitude()

float magnitude ( int  bin )

inline

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

magnitudeFast()

float magnitudeFast ( int  bin )

inline

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!

not_supported()

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

inlineprotectedvirtualinherited

notifyAudioChange()

void notifyAudioChange ( AudioInfo  info )

inlineprotectedinherited

operator bool()

operator bool ( )

inlineoverridevirtual

Reimplemented from AudioStream.

phase()

float phase ( int  bin )

inline

calculates the phase

processSamples()

template<typename T >

void processSamples ( const void *  data, size_t  count  )

inlineprotected

readBytes()

size_t readBytes ( uint8_t *  data, size_t  len  )

inlineoverridevirtual

Provides the result of a reverse FFT.

Reimplemented from AudioStream.

readSilence()

virtual size_t readSilence ( uint8_t *  buffer, size_t  length  )

inlinevirtualinherited

Source to generate silence: just sets the buffer to 0.

reference()

template<typename T >

T & reference ( )

inline

Provides the reference pointer.

refillReadBuffer()

void refillReadBuffer ( )

inlineprotectedinherited

Refill small read buffer (e.g. 8 bytes) to avoid single byte reads when calling read()

removeNotifyAudioChange()

virtual bool removeNotifyAudioChange ( AudioInfoSupport &  bi )

inlinevirtualinherited

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

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

reset()

void reset ( )

inline

Just resets the current_pos e.g. to start a new cycle.

result()

AudioFFTResult result ( )

inline

Determines the result values in the max magnitude bin.

resultArray()

template<int N>

void resultArray ( AudioFFTResult(&)  result[N] )

inline

Determines the N biggest result values.

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

resultTimeBegin()

unsigned long resultTimeBegin ( )

inline

time before the fft

rfft()

void rfft ( )

inlineprotected

reverse fft

rfftWriteData()

void rfftWriteData ( BaseBuffer< uint8_t > &  data )

inlineprotected

write reverse fft result to buffer to make it available for readBytes

setAudioInfo()

void setAudioInfo ( AudioInfo  info )

inlineoverridevirtual

Notify change of audio information.

Reimplemented from AudioStream.

setBin() [1/2]

bool setBin ( int  idx, float  real, float  img  )

inline

sets the value of a bin

setBin() [2/2]

bool setBin ( int  pos, FFTBin &  bin  )

inline

sets the value of a bin

setNotifyActive()

void setNotifyActive ( bool  flag )

inlineinherited

Deactivate/Reactivate automatic AudioInfo updates: (default is active)

setWriteBufferSize()

void setWriteBufferSize ( int  size )

inlineinherited

size()

int size ( )

inline

The number of bins used by the FFT which are relevant for the result.

toMEL()

float * toMEL ( int  n_bins, float  min_freq = 0.0f, float  max_freq = 0.0f  )

inline

Convert the FFT result to MEL spectrum.

windowedSample()

template<typename T >

T windowedSample ( T  sample, int  pos  )

inlineprotected

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 MemoryStream, AudioStreamWrapper, BufferedTaskStream, RingBufferStream, BufferedStream, and URLStream.

writeIFFT()

template<typename T >

void writeIFFT ( float *  data, int  len  )

inlineprotected

writeSilence()

virtual void writeSilence ( size_t  len )

inlinevirtualinherited

Writes len bytes of silence (=0).

writeStrideBuffer()

bool writeStrideBuffer ( uint8_t *  buffer, size_t  len  )

inlineprotected

Member Data Documentation

_timeout

int _timeout = 10

protectedinherited

bins

int bins = 0

protected

cfg

AudioFFTConfig cfg

protected

current_pos

int current_pos = 0

protected

has_rfft_data

bool has_rfft_data = false

protected

info

AudioInfo info

protectedinherited

is_notify_active

bool is_notify_active = true

protectedinherited

l_magnitudes

Vector<float> l_magnitudes {0}

protected

mel_bins

Vector<float> mel_bins {0}

protected

notify_vector

Vector<AudioInfoSupport*> notify_vector

protectedinherited

p_driver

FFTDriver* p_driver = nullptr

protected

rfft_add

FFTInverseOverlapAdder rfft_add {0}

protected

rfft_data

RingBuffer<uint8_t> rfft_data {0}

protected

step_data

Vector<float> step_data {0}

protected

stride_buffer

SingleBuffer<uint8_t> stride_buffer {0}

protected

timestamp

unsigned long timestamp = 0l

protected

timestamp_begin

unsigned long timestamp_begin = 0l

protected

tmp_in

RingBuffer<uint8_t> tmp_in {0}

protectedinherited

tmp_out

RingBuffer<uint8_t> tmp_out {0}

protectedinherited

write_buffer_size

int write_buffer_size = MAX_SINGLE_CHARS

protectedinherited

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

• src/AudioTools/AudioLibs/AudioFFT.h