AudioFFT using the fixedpoint-fft library. CalcT selects the calculation type (default int16_t, see FFTDriverFixedFFT); pick int8_t on RAM-constrained plain AVR targets, or float/double on FPU-equipped targets. More...

#include <AudioFixedFFT.h>

Inheritance diagram for AudioFixedFFT< CalcT >:

[legend]

Collaboration diagram for AudioFixedFFT< CalcT >:

[legend]

Public Member Functions
	AudioFixedFFT ()

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 ()

FFTDriverFixedFFT< CalcT > *	driverEx ()

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, using the same (cached) filterbank as toMEL().

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

CalcT *	imgArray ()
	Provides the imaginary array returned by the FFT.

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.

CalcT *	realArray ()
	Provides the real array returned by the FFT.

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, bool power=false)

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)

template<typename T >
void	processStrideBuffer ()
	FFT of the full stride buffer, then drop `stride` samples.

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

bool	updateMelFilterbank (int n_bins, float min_freq, float max_freq)
	(Re)builds the cached sparse filterbank if any parameter changed

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)

Static Protected Member Functions
static float	hzToMel (float hz)

static float	melToHz (float mel)

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< MelFilter >	mel_filters {0}

int	mel_length = 0

float	mel_max_freq = -1.0f

float	mel_min_freq = -1.0f

int	mel_n_bins = 0

int	mel_sample_rate = 0

Vector< float >	mel_weights {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

template<typename CalcT = int16_t>
class audio_tools::AudioFixedFFT< CalcT >

AudioFFT using the fixedpoint-fft library. CalcT selects the calculation type (default int16_t, see FFTDriverFixedFFT); pick int8_t on RAM-constrained plain AVR targets, or float/double on FPU-equipped targets.

Author: Phil Schatzmann

Copyright: GPLv3

Constructor & Destructor Documentation

◆ AudioFixedFFT()

template<typename CalcT = int16_t>

AudioFixedFFT ( )

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 MP3EncoderShine, PureDataStream, PWMAudioOutput< PWMDriverT >, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, FormatConverterStream, Pipeline, ResampleStream, ResampleStreamT< TInterpolator >, and SupportedRatesStream.

◆ available()

int available ( )

inlineoverridevirtualinherited

Data available for reverse fft.

Reimplemented from BaseStream.

◆ availableForWrite()

int availableForWrite ( )

inlineoverridevirtualinherited

We try to fill the buffer at once.

Reimplemented from BaseStream.

◆ begin() [1/2]

bool begin ( )

inlineoverridevirtualinherited

starts the processing

Reimplemented from BaseStream.

◆ begin() [2/2]

bool begin ( AudioFFTConfig info )

inlineinherited

starts the processing

◆ bytesPerSample()

int bytesPerSample ( )

inlineprotectedinherited

bytes per sample in the audio data: 24 bit samples use the int24_t representation (4 bytes unless USE_3BYTE_INT24 is defined)

◆ clearBins()

void clearBins ( )

inlineinherited

clears the fft data

◆ clearNotifyAudioChange()

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

◆ config()

AudioFFTConfig & config ( )

inlineinherited

Provides the actual configuration.

◆ defaultConfig()

AudioFFTConfig defaultConfig ( RxTxMode mode = TX_MODE )

inlineinherited

Provides the default configuration.

◆ driver()

FFTDriver * driver ( )

inlineinherited

provides access to the FFTDriver which implements the basic FFT functionality

◆ driverEx()

template<typename CalcT = int16_t>

FFTDriverFixedFFT< CalcT > * driverEx ( )

inline

◆ end()

void end ( )

inlineoverridevirtualinherited

Release the allocated memory.

Reimplemented from BaseStream.

◆ fft()

template<typename T >

void fft ( )

inlineprotectedinherited

◆ flush()

virtual void flush ( )

inlineoverridevirtualinherited

◆ frequency()

float frequency ( int bin )

inlineinherited

Determines the frequency of the indicated bin.

◆ frequencyToBin()

int frequencyToBin ( int freq )

inlineinherited

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`
	)

inlineinherited

Convert MEL spectrum back to linear frequency spectrum, using the same (cached) filterbank as toMEL().

Parameters

values	Pointer to MEL spectrum values
n_bins	Number of MEL bins

Returns: bool Success status

◆ getBin()

bool getBin	(	int	pos,
		FFTBin &	bin
	)

inlineinherited

gets the value of a bin

◆ hzToMel()

static float hzToMel ( float hz )

inlinestaticprotectedinherited

◆ imgArray()

template<typename CalcT = int16_t>

CalcT * imgArray ( )

inline

Provides the imaginary array returned by the FFT.

◆ insertSorted()

template<int N>

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

inlineprotectedinherited

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 )

inlineprotectedinherited

◆ length()

int length ( )

inlineinherited

The number of samples.

◆ magnitude()

float magnitude ( int bin )

inlineinherited

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

◆ magnitudeFast()

float magnitudeFast ( int bin )

inlineinherited

◆ magnitudes()

float * magnitudes ( )

inlineinherited

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

◆ magnitudesFast()

float * magnitudesFast ( )

inlineinherited

Provides the magnitudes w/o calling the square root function as array of size size(). Please note that this method is allocating additinal memory!

◆ melToHz()

static float melToHz ( float mel )

inlinestaticprotectedinherited

◆ not_supported()

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

inlineprotectedvirtualinherited

◆ notifyAudioChange()

void notifyAudioChange ( AudioInfo info )

inlineprotectedinherited

◆ operator bool()

operator bool ( )

inlineoverridevirtualinherited

Reimplemented from AudioStream.

◆ phase()

float phase ( int bin )

inlineinherited

calculates the phase

◆ processSamples()

template<typename T >

void processSamples	(	const void *	data,
		size_t	count
	)

inlineprotectedinherited

◆ processStrideBuffer()

template<typename T >

void processStrideBuffer ( )

inlineprotectedinherited

FFT of the full stride buffer, then drop stride samples.

◆ readBytes()

size_t readBytes	(	uint8_t *	data,
		size_t	len
	)

inlineoverridevirtualinherited

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.

◆ realArray()

template<typename CalcT = int16_t>

CalcT * realArray ( )

inline

Provides the real array returned by the FFT.

◆ reference()

template<typename T >

T & reference ( )

inlineinherited

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 ( )

inlineinherited

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

◆ result()

AudioFFTResult result ( )

inlineinherited

Determines the result values in the max magnitude bin.

◆ resultArray()

template<int N>

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

inlineinherited

Determines the N biggest result values.

◆ resultTime()

unsigned long resultTime ( )

inlineinherited

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 ( )

inlineinherited

time before the fft

◆ rfft()

void rfft ( )

inlineprotectedinherited

reverse fft

◆ rfftWriteData()

void rfftWriteData ( BaseBuffer< uint8_t > & data )

inlineprotectedinherited

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

◆ setAudioInfo()

void setAudioInfo ( AudioInfo info )

inlineoverridevirtualinherited

Notify change of audio information.

Reimplemented from AudioStream.

◆ setBin() [1/2]

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

inlineinherited

sets the value of a bin

◆ setBin() [2/2]

bool setBin	(	int	pos,
		FFTBin &	bin
	)

inlineinherited

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 ( )

inlineinherited

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`,
		bool	power = `false`
	)

inlineinherited

Convert the FFT result to MEL spectrum. The triangular filterbank uses fractional (HTK style) weights, so no filter collapses to zero width, and it is computed once and cached until the parameters change.

Parameters

n_bins	number of mel bands (<= 0: size())
min_freq	lower edge in Hz (<= 0: frequency(0))
max_freq	upper edge in Hz (<= 0: frequency(size() - 1))
power	use the power spectrum \|X\|^2 instead of the magnitude \|X\|

◆ updateMelFilterbank()

bool updateMelFilterbank	(	int	n_bins,
		float	min_freq,
		float	max_freq
	)

inlineprotectedinherited

(Re)builds the cached sparse filterbank if any parameter changed

◆ windowedSample()

template<typename T >

T windowedSample	(	T	sample,
		int	pos
	)

inlineprotectedinherited

◆ write() [1/2]

size_t write	(	const uint8_t *	data,
		size_t	len
	)

inlineoverridevirtualinherited

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
	)

inlineprotectedinherited

◆ writeSilence()

virtual void writeSilence ( size_t len )

inlinevirtualinherited

Writes len bytes of silence (=0).

◆ writeStrideBuffer()

bool writeStrideBuffer	(	uint8_t *	buffer,
		size_t	len
	)

inlineprotectedinherited

Member Data Documentation

◆ _timeout

int _timeout = 10

protectedinherited

◆ bins

int bins = 0

protectedinherited

◆ cfg

AudioFFTConfig cfg

protectedinherited

◆ current_pos

int current_pos = 0

protectedinherited

◆ has_rfft_data

bool has_rfft_data = false

protectedinherited

◆ info

AudioInfo info

protectedinherited

◆ is_notify_active

bool is_notify_active = true

protectedinherited

◆ l_magnitudes

Vector<float> l_magnitudes {0}

protectedinherited

◆ mel_bins

Vector<float> mel_bins {0}

protectedinherited

◆ mel_filters

Vector<MelFilter> mel_filters {0}

protectedinherited

◆ mel_length

int mel_length = 0

protectedinherited

◆ mel_max_freq

float mel_max_freq = -1.0f

protectedinherited

◆ mel_min_freq

float mel_min_freq = -1.0f

protectedinherited

◆ mel_n_bins

int mel_n_bins = 0

protectedinherited

◆ mel_sample_rate

int mel_sample_rate = 0

protectedinherited

◆ mel_weights

Vector<float> mel_weights {0}

protectedinherited

◆ notify_vector

Vector<AudioInfoSupport*> notify_vector

protectedinherited

◆ p_driver

FFTDriver* p_driver = nullptr

protectedinherited

◆ rfft_add

FFTInverseOverlapAdder rfft_add {0}

protectedinherited

◆ rfft_data

RingBuffer<uint8_t> rfft_data {0}

protectedinherited

◆ step_data

Vector<float> step_data {0}

protectedinherited

◆ stride_buffer

SingleBuffer<uint8_t> stride_buffer {0}

protectedinherited

◆ timestamp

unsigned long timestamp = 0l

protectedinherited

◆ timestamp_begin

unsigned long timestamp_begin = 0l

protectedinherited

◆ 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

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

src/AudioTools/FFT/AudioFixedFFT.h

Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ AudioFixedFFT()

Member Function Documentation

◆ addNotifyAudioChange()

◆ audioInfo()

◆ audioInfoOut()

◆ available()

◆ availableForWrite()

◆ begin() [1/2]

◆ begin() [2/2]

◆ bytesPerSample()

◆ clearBins()

◆ clearNotifyAudioChange()

◆ config()

◆ defaultConfig()

◆ driver()

◆ driverEx()

◆ end()

◆ fft()

◆ flush()

◆ frequency()

◆ frequencyToBin()

◆ fromMEL()

◆ getBin()

◆ hzToMel()

◆ imgArray()

◆ insertSorted()

◆ isNotifyActive()

◆ isPowerOfTwo()

◆ length()

◆ magnitude()

◆ magnitudeFast()

◆ magnitudes()

◆ magnitudesFast()

◆ melToHz()

◆ not_supported()

◆ notifyAudioChange()

◆ operator bool()

◆ phase()

◆ processSamples()

◆ processStrideBuffer()

◆ readBytes()

◆ readSilence()

◆ realArray()

◆ reference()

◆ refillReadBuffer()

◆ removeNotifyAudioChange()

◆ reset()

◆ result()

◆ resultArray()

◆ resultTime()

◆ resultTimeBegin()

◆ rfft()

◆ rfftWriteData()

◆ setAudioInfo()

◆ setBin() [1/2]

◆ setBin() [2/2]

◆ setNotifyActive()

◆ setWriteBufferSize()

◆ size()

◆ toMEL()

◆ updateMelFilterbank()

◆ windowedSample()

◆ write() [1/2]

◆ write() [2/2]

◆ writeIFFT()

◆ writeSilence()

◆ writeStrideBuffer()

Member Data Documentation

◆ _timeout

◆ bins

◆ cfg

◆ current_pos

◆ has_rfft_data

◆ info