N-Band Equalizer using FIR filters with logarithmically spaced bands. More...

#include <EqualizerNBands.h>

Inheritance diagram for EqualizerNBands< SampleT, AccT, NUM_TAPS, NUM_BANDS >:

Classes
class	EQFIRFilter

Public Member Functions
	EqualizerNBands ()
	EqualizerNBands (AudioOutput &out)
	EqualizerNBands (AudioStream &stream)
	EqualizerNBands (Print &out)
	EqualizerNBands (Stream &in)
	~EqualizerNBands ()
virtual void	addNotifyAudioChange (AudioInfoSupport &bi)
	Adds target to be notified about audio changes.
virtual void	addNotifyAudioChange (AudioInfoSupport &bi)
	Adds target to be notified about audio changes.
virtual AudioInfo	audioInfo () override
	provides the actual input AudioInfo
virtual AudioInfo	audioInfo () override
	provides the actual input AudioInfo
virtual AudioInfo	audioInfoOut ()
virtual AudioInfo	audioInfoOut ()
virtual int	available () override
virtual int	available () override
virtual int	availableForWrite () override
virtual int	availableForWrite () override
bool	begin () override
	Initializes the equalizer with the current audio info.
bool	begin (AudioInfo info)
virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.
virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.
void	end ()
void	flush () override
int	getBandCount () const
	Get number of bands.
float	getBandDB (int band) const
float	getBandFrequency (int band) const
float	getBandGain (int band)
	Get current gain for a specific band as normalized volume (-1.0 to 1.0).
bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.
bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.
virtual	operator bool ()
virtual	operator bool ()
size_t	readBytes (uint8_t *data, size_t len) override
virtual size_t	readSilence (uint8_t *buffer, size_t length)
	Source to generate silence: just sets the buffer to 0.
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.
virtual bool	removeNotifyAudioChange (AudioInfoSupport &bi)
	Removes a target in order not to be notified about audio changes.
virtual void	setAudioInfo (AudioInfo newInfo) override
	Defines the input AudioInfo.
virtual void	setAudioInfo (AudioInfo newInfo) override
	Defines the input AudioInfo.
void	setAutoUpdate (bool enabled)
bool	setBandDB (int band, float gainDb)
bool	setBandGain (int band, float volume)
bool	setBandGains (float volume)
	Set same gain for all frequency bands.
void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active).
void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active).
virtual void	setOutput (AudioOutput &out)
	Defines/Changes the output target and registers for audio change notifications.
void	setOutput (Print &out) override
virtual void	setStream (AudioStream &io)
	Defines/Changes the input & output and registers for audio change notifications.
void	setStream (Stream &io) override
void	setWriteBufferSize (int size)
void	setWriteBufferSize (int size)
bool	update ()
virtual size_t	write (uint8_t ch) override
size_t	write (const uint8_t *data, size_t len) override
virtual void	writeSilence (size_t len)
	Writes len bytes of silence (=0).
virtual void	writeSilence (size_t len)
	Writes len bytes of silence (=0).

Protected Member Functions
void	enterCritical ()
void	exitCritical ()
void	initializeKernel (volatile int16_t *kernel)
template<typename T>
float	map (T x, T in_min, T in_max, T out_min, T out_max)
void	maybeUpdateKernel ()
virtual int	not_supported (int out, const char *msg="")
virtual int	not_supported (int out, const char *msg="")
void	notifyAudioChange (AudioInfo info)
void	notifyAudioChange (AudioInfo info)
void	preCalculateWindow ()
void	refillReadBuffer ()
	Refill small read buffer (e.g. 8 bytes) to avoid single byte reads when calling read().
void	refillReadBuffer ()
	Refill small read buffer (e.g. 8 bytes) to avoid single byte reads when calling read().
void	setupFrequencies (int sampleRate)
float	sinc (float x)
bool	updateFIRKernel ()

Protected Attributes
int	_timeout = 10
volatile int16_t *	activeKernel
bool	autoUpdate = false
float	centerFreqs [NUM_BANDS]
int	currentSampleRate = 0
FilteredStream< SampleT, SampleT >	filtered
Vector< EQFIRFilter >	fir_vector
	Vector of FIR filters for each channel.
float	gains [NUM_BANDS] = {0}
volatile bool	gainsDirty = false
AudioInfo	info
bool	is_notify_active = true
volatile bool	isUpdating = false
int16_t	kernelA [NUM_TAPS]
int16_t	kernelB [NUM_TAPS]
Vector< AudioInfoSupport * >	notify_vector
Stream *	p_io = nullptr
	Input stream for read operations.
Print *	p_out = nullptr
	Output stream for write operations.
float	pendingGains [NUM_BANDS] = {0}
float	tempFloat [NUM_TAPS] = {0}
RingBuffer< uint8_t >	tmp_in {0}
RingBuffer< uint8_t >	tmp_out {0}
volatile int16_t *	updateKernel
float	windowCoeffs [NUM_TAPS]
int	write_buffer_size = 8

Static Protected Attributes
static constexpr float	Q15_SCALE = 32767.0f

Detailed Description

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>
class audio_tools::EqualizerNBands< SampleT, AccT, NUM_TAPS, NUM_BANDS >

N-Band Equalizer using FIR filters with logarithmically spaced bands.

This class implements a graphic equalizer with configurable number of bands using FIR (Finite Impulse Response) filtering. Frequency bands are logarithmically spaced between 20Hz and Nyquist frequency.

Features:

Template-based configuration for number of taps and bands
Fixed-point Q15 arithmetic for efficient processing on embedded systems
Blackman windowing for reduced spectral leakage
Per-band gain control (-90dB to +12dB)
Multi-channel support
Double-buffered kernel for thread-safe real-time updates

Thread Safety: Uses double-buffering with two kernel buffers. Audio processing reads from the active kernel while updates are written to the inactive kernel. An atomic pointer swap ensures glitch-free transitions without blocking audio processing.

Template Parameters

NUM_TAPS	Number of FIR filter taps (higher = sharper transitions, more CPU usage). Typical values: 64, 128, 256
NUM_BANDS	Number of frequency bands. Typical values: 3, 5, 10, 31

Note: NUM_TAPS should be odd for symmetric filter response; Higher NUM_TAPS values require more memory and processing time

Constructor & Destructor Documentation

◆ EqualizerNBands() [1/5]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

EqualizerNBands ( )

inline

◆ EqualizerNBands() [2/5]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

EqualizerNBands ( Print & out )

inline

Constructor with Print output

Parameters

out	Print stream for output

◆ EqualizerNBands() [3/5]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

EqualizerNBands ( Stream & in )

inline

Constructor with Stream input

Parameters

in	Stream for input

◆ EqualizerNBands() [4/5]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

EqualizerNBands ( AudioOutput & out )

inline

Constructor with AudioOutput

Parameters

out	AudioOutput for output with automatic audio change notifications

◆ EqualizerNBands() [5/5]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

EqualizerNBands ( AudioStream & stream )

inline

Constructor with AudioStream

Parameters

stream AudioStream for input/output with automatic audio change notifications

◆ ~EqualizerNBands()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

~EqualizerNBands ( )

inline

Member Function Documentation

◆ addNotifyAudioChange() [1/2]

virtual void addNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

Adds target to be notified about audio changes.

Reimplemented in CodecNOP, CodecNOP, EncodedAudioOutput, and EncodedAudioStream.

◆ addNotifyAudioChange() [2/2]

virtual void addNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

Adds target to be notified about audio changes.

Reimplemented in CodecNOP, CodecNOP, EncodedAudioOutput, and EncodedAudioStream.

◆ audioInfo() [1/2]

virtual AudioInfo audioInfo ( )

inlineoverridevirtualinherited

◆ audioInfo() [2/2]

virtual AudioInfo audioInfo ( )

inlineoverridevirtualinherited

◆ audioInfoOut() [1/2]

virtual AudioInfo audioInfoOut ( )

inlinevirtualinherited

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

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

◆ audioInfoOut() [2/2]

virtual AudioInfo audioInfoOut ( )

inlinevirtualinherited

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

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

◆ available() [1/2]

virtual int available ( )

inlineoverridevirtualinherited

Reimplemented from Stream.

Reimplemented in A2DPStream, AnalogAudioStream, AudioStreamWrapper, AudioStreamWrapper, BufferedStream, BufferedStream, CallbackStream, CallbackStream, CatStream, CatStream, ConverterStream< T >, ConverterStream< T >, DynamicMemoryStream, DynamicMemoryStream, FilteredStream< T, TF >, FilteredStream< T, TF >, FilteredStream< int16_t, int16_t >, GeneratedSoundStream< T >, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, InputMerge< T >, InputMerge< T >, InputMixer< T, SumT >, InputMixer< T, SumT >, MemoryStream, MemoryStream, ProgressStream, ProgressStream, QueueStream< T >, QueueStream< T >, QueueStream< uint8_t >, ReformatBaseStream, RingBufferStream, RingBufferStream, Throttle, Throttle, TimedStream, AudioBLEClient, AudioBLEClient, AudioBLEServer, AudioBLEServer, AudioEffectStream, AudioEffectStreamT< T >, AudioFFTBase, AudioKitStream, AudioLoRa, AudioMP34DT05, AudioStreamWrapper, AutomaticGainControlStream, BufferedStream, BufferedTaskStream, CallbackStream, CatStream, ChannelFormatConverterStream, ChannelFormatConverterStreamT< T >, ConverterStream< T >, DynamicMemoryStream, Equalizer3BandsPerChannelT< T >, Equalizer3BandsPerChannelT< float >, Equalizer3BandsT< T >, Equalizer3BandsT< float >, ESPNowStream, FadeStream, FaustStream< DSP >, FileLoopT< FileType >, FileLoopT< File >, FilteredStream< T, TF >, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, GeneratedSoundStream< T >, HammingFEC< bytecount, block_t >, HLSStreamT< URLStream >, HLSStreamT< URLStreamESP32 >, HttpRequest, I2SCodecStream, I2SStream, ICYStreamT< T >, ICYStreamT< URLStream >, ICYStreamT< URLStreamESP32 >, InputMerge< T >, InputMixer< T, SumT >, MeasuringStream, MemoryStream, MiniAudioStream, NRF24Stream, NumberFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, Pipeline, Pipeline::ModifyingStreamAdapter, ProgressStream, QualityAnalysisStream, QueueStream< T >, ReedSolomonFEC< bytecount, additional_bytes >, ReformatBaseStream, RingBufferStream, SPIAudioSlave, StdioStream, SupportedRatesStream, TfLiteAudioStream, Throttle, TimedStream, UDPStream, URLStream, URLStreamBufferedT< T >, URLStreamBufferedT< ICYStream >, URLStreamBufferedT< ICYStreamESP32 >, URLStreamBufferedT< URLStream >, URLStreamBufferedT< URLStreamESP32 >, USBAudioStreamBase, VBANStream, and VolumeStream.

◆ available() [2/2]

virtual int available ( )

inlineoverridevirtualinherited

Reimplemented from Stream.

Reimplemented in A2DPStream, AnalogAudioStream, AudioStreamWrapper, AudioStreamWrapper, BufferedStream, BufferedStream, CallbackStream, CallbackStream, CatStream, CatStream, ConverterStream< T >, ConverterStream< T >, DynamicMemoryStream, DynamicMemoryStream, FilteredStream< T, TF >, FilteredStream< T, TF >, FilteredStream< int16_t, int16_t >, GeneratedSoundStream< T >, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, InputMerge< T >, InputMerge< T >, InputMixer< T, SumT >, InputMixer< T, SumT >, MemoryStream, MemoryStream, ProgressStream, ProgressStream, QueueStream< T >, QueueStream< T >, QueueStream< uint8_t >, ReformatBaseStream, RingBufferStream, RingBufferStream, Throttle, Throttle, TimedStream, AudioBLEClient, AudioBLEClient, AudioBLEServer, AudioBLEServer, AudioEffectStream, AudioEffectStreamT< T >, AudioFFTBase, AudioKitStream, AudioLoRa, AudioMP34DT05, AudioStreamWrapper, AutomaticGainControlStream, BufferedStream, BufferedTaskStream, CallbackStream, CatStream, ChannelFormatConverterStream, ChannelFormatConverterStreamT< T >, ConverterStream< T >, DynamicMemoryStream, Equalizer3BandsPerChannelT< T >, Equalizer3BandsPerChannelT< float >, Equalizer3BandsT< T >, Equalizer3BandsT< float >, ESPNowStream, FadeStream, FaustStream< DSP >, FileLoopT< FileType >, FileLoopT< File >, FilteredStream< T, TF >, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, GeneratedSoundStream< T >, HammingFEC< bytecount, block_t >, HLSStreamT< URLStream >, HLSStreamT< URLStreamESP32 >, HttpRequest, I2SCodecStream, I2SStream, ICYStreamT< T >, ICYStreamT< URLStream >, ICYStreamT< URLStreamESP32 >, InputMerge< T >, InputMixer< T, SumT >, MeasuringStream, MemoryStream, MiniAudioStream, NRF24Stream, NumberFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, Pipeline, Pipeline::ModifyingStreamAdapter, ProgressStream, QualityAnalysisStream, QueueStream< T >, ReedSolomonFEC< bytecount, additional_bytes >, ReformatBaseStream, RingBufferStream, SPIAudioSlave, StdioStream, SupportedRatesStream, TfLiteAudioStream, Throttle, TimedStream, UDPStream, URLStream, URLStreamBufferedT< T >, URLStreamBufferedT< ICYStream >, URLStreamBufferedT< ICYStreamESP32 >, URLStreamBufferedT< URLStream >, URLStreamBufferedT< URLStreamESP32 >, USBAudioStreamBase, VBANStream, and VolumeStream.

◆ availableForWrite() [1/2]

virtual int availableForWrite ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in A2DPStream, AbstractURLStream, AnalogAudioStream, AudioStreamWrapper, AudioStreamWrapper, ConverterStream< T >, ConverterStream< T >, DynamicMemoryStream, DynamicMemoryStream, EncodedAudioStream, FilteredStream< T, TF >, FilteredStream< T, TF >, FilteredStream< int16_t, int16_t >, MemoryStream, MemoryStream, ProgressStream, ProgressStream, QueueStream< T >, QueueStream< T >, QueueStream< uint8_t >, ReformatBaseStream, RingBufferStream, RingBufferStream, Throttle, Throttle, TimedStream, AudioBLEClient, AudioBLEClient, AudioBLEServer, AudioBLEServer, AudioEffectStream, AudioEffectStreamT< T >, AudioFFTBase, AudioLoRa, AudioStreamWrapper, AutomaticGainControlStream, ChannelFormatConverterStream, ChannelFormatConverterStreamT< T >, ConverterStream< T >, DynamicMemoryStream, EncodedAudioStream, Equalizer3BandsPerChannelT< T >, Equalizer3BandsPerChannelT< float >, Equalizer3BandsT< T >, Equalizer3BandsT< float >, ESPNowStream, FadeStream, FaustStream< DSP >, FilteredStream< T, TF >, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, HammingFEC< bytecount, block_t >, I2SCodecStream, I2SStream, MeasuringStream, MemoryStream, MiniAudioStream, NRF24Stream, NumberFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, Pipeline, ProgressStream, QualityAnalysisStream, QueueStream< T >, ReedSolomonFEC< bytecount, additional_bytes >, ReformatBaseStream, RingBufferStream, SPIAudioSlave, StdioStream, SupportedRatesStream, Throttle, TimedStream, UDPStream, URLStreamESP32, USBAudioStreamBase, VBANStream, and VolumeStream.

◆ availableForWrite() [2/2]

virtual int availableForWrite ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in A2DPStream, AbstractURLStream, AnalogAudioStream, AudioStreamWrapper, AudioStreamWrapper, ConverterStream< T >, ConverterStream< T >, DynamicMemoryStream, DynamicMemoryStream, EncodedAudioStream, FilteredStream< T, TF >, FilteredStream< T, TF >, FilteredStream< int16_t, int16_t >, MemoryStream, MemoryStream, ProgressStream, ProgressStream, QueueStream< T >, QueueStream< T >, QueueStream< uint8_t >, ReformatBaseStream, RingBufferStream, RingBufferStream, Throttle, Throttle, TimedStream, AudioBLEClient, AudioBLEClient, AudioBLEServer, AudioBLEServer, AudioEffectStream, AudioEffectStreamT< T >, AudioFFTBase, AudioLoRa, AudioStreamWrapper, AutomaticGainControlStream, ChannelFormatConverterStream, ChannelFormatConverterStreamT< T >, ConverterStream< T >, DynamicMemoryStream, EncodedAudioStream, Equalizer3BandsPerChannelT< T >, Equalizer3BandsPerChannelT< float >, Equalizer3BandsT< T >, Equalizer3BandsT< float >, ESPNowStream, FadeStream, FaustStream< DSP >, FilteredStream< T, TF >, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, HammingFEC< bytecount, block_t >, I2SCodecStream, I2SStream, MeasuringStream, MemoryStream, MiniAudioStream, NRF24Stream, NumberFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, Pipeline, ProgressStream, QualityAnalysisStream, QueueStream< T >, ReedSolomonFEC< bytecount, additional_bytes >, ReformatBaseStream, RingBufferStream, SPIAudioSlave, StdioStream, SupportedRatesStream, Throttle, TimedStream, UDPStream, URLStreamESP32, USBAudioStreamBase, VBANStream, and VolumeStream.

◆ begin() [1/2]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool begin ( )

inlineoverridevirtual

Initializes the equalizer with the current audio info.

Reimplemented from BaseStream.

◆ begin() [2/2]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool begin ( AudioInfo info )

inline

◆ clearNotifyAudioChange() [1/2]

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >, RTSPClient< EthernetClient, EthernetUDP >, and RTSPClient< WiFiClient, WiFiUDP >.

◆ clearNotifyAudioChange() [2/2]

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >, RTSPClient< EthernetClient, EthernetUDP >, and RTSPClient< WiFiClient, WiFiUDP >.

◆ end()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void end ( )

inlinevirtual

Reimplemented from BaseStream.

◆ enterCritical()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void enterCritical ( )

inlineprotected

◆ exitCritical()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void exitCritical ( )

inlineprotected

◆ flush()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void flush ( )

inlineoverridevirtual

Reimplemented from BaseStream.

◆ getBandCount()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

int getBandCount ( ) const

inline

Get number of bands.

◆ getBandDB()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float getBandDB ( int band ) const

inline

Get current gain for a specific band in dB

Parameters

band	Band index (0 to NUM_BANDS-1)

Returns: Gain in dB (-90 to +12), or 0 if band index invalid

◆ getBandFrequency()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float getBandFrequency ( int band ) const

inline

Get center frequency for a specific band

Parameters

band	Band index (0 to NUM_BANDS-1)

Returns: Center frequency in Hz, or 0 if band index invalid

◆ getBandGain()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float getBandGain ( int band )

inline

Get current gain for a specific band as normalized volume (-1.0 to 1.0).

◆ initializeKernel()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void initializeKernel ( volatile int16_t * kernel )

inlineprotected

◆ isNotifyActive() [1/2]

bool isNotifyActive ( )

inlineinherited

Checks if the automatic AudioInfo update is active.

◆ isNotifyActive() [2/2]

bool isNotifyActive ( )

inlineinherited

Checks if the automatic AudioInfo update is active.

◆ map()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

template<typename T>

float map	(	T	x,
		T	in_min,
		T	in_max,
		T	out_min,
		T	out_max )

inlineprotected

◆ maybeUpdateKernel()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void maybeUpdateKernel ( )

inlineprotected

◆ not_supported() [1/2]

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

inlineprotectedvirtualinherited

◆ not_supported() [2/2]

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

inlineprotectedvirtualinherited

◆ notifyAudioChange() [1/2]

void notifyAudioChange ( AudioInfo info )

inlineprotectedinherited

◆ notifyAudioChange() [2/2]

void notifyAudioChange ( AudioInfo info )

inlineprotectedinherited

◆ operator bool() [1/2]

virtual operator bool ( )

inlinevirtualinherited

◆ operator bool() [2/2]

virtual operator bool ( )

inlinevirtualinherited

◆ preCalculateWindow()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void preCalculateWindow ( )

inlineprotected

◆ readBytes()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

size_t readBytes	(	uint8_t *	data,
		size_t	len )

inlineoverridevirtual

Reimplemented from AudioStream.

◆ readSilence() [1/2]

virtual size_t readSilence	(	uint8_t *	buffer,
		size_t	length )

inlinevirtualinherited

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

◆ readSilence() [2/2]

virtual size_t readSilence	(	uint8_t *	buffer,
		size_t	length )

inlinevirtualinherited

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

◆ refillReadBuffer() [1/2]

void refillReadBuffer ( )

inlineprotectedinherited

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

◆ refillReadBuffer() [2/2]

void refillReadBuffer ( )

inlineprotectedinherited

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

◆ removeNotifyAudioChange() [1/2]

virtual bool removeNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

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

◆ removeNotifyAudioChange() [2/2]

virtual bool removeNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

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

◆ setAudioInfo() [1/2]

virtual void setAudioInfo ( AudioInfo info )

inlineoverridevirtualinherited

Defines the input AudioInfo.

Implements AudioInfoSupport.

Reimplemented in AdapterAudioOutputToAudioStream, AudioInputMonitor, AudioInputMonitor, CallbackStream, CallbackStream, EncodedAudioStream, GeneratedSoundStream< T >, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, ProgressStream, ProgressStream, TimedStream, TimerCallbackAudioStream, TimerCallbackAudioStream, VolumeMeter, and VolumeMeter.

◆ setAudioInfo() [2/2]

virtual void setAudioInfo ( AudioInfo info )

inlineoverridevirtualinherited

Defines the input AudioInfo.

Implements AudioInfoSupport.

Reimplemented in AdapterAudioOutputToAudioStream, AudioInputMonitor, AudioInputMonitor, CallbackStream, CallbackStream, EncodedAudioStream, GeneratedSoundStream< T >, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, ProgressStream, ProgressStream, TimedStream, TimerCallbackAudioStream, TimerCallbackAudioStream, VolumeMeter, and VolumeMeter.

◆ setAutoUpdate()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void setAutoUpdate ( bool enabled )

inline

Enable/disable automatic kernel updates during read/write

Parameters

enabled When true, pending gain changes are applied automatically

◆ setBandDB()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool setBandDB	(	int	band,
		float	gainDb )

inline

Set gain for a specific band directly in dB

Parameters

band	Band index (0 to NUM_BANDS-1)
gainDb	Gain in dB (-90 to +12). The lower limit matches Q15 dynamic range; the upper limit prevents clipping.

◆ setBandGain()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool setBandGain	(	int	band,
		float	volume )

inline

Set gain for a specific frequency band

Parameters

band	Band index (0 to NUM_BANDS-1)
volume	Volume level (-1.0 to 1.0) mapped to -12dB to +12dB. For deeper cuts use setBandDB() directly.

◆ setBandGains()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool setBandGains ( float volume )

inline

Set same gain for all frequency bands.

◆ setNotifyActive() [1/2]

void setNotifyActive ( bool flag )

inlineinherited

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

◆ setNotifyActive() [2/2]

void setNotifyActive ( bool flag )

inlineinherited

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

◆ setOutput() [1/2]

virtual void setOutput ( AudioOutput & out )

inlinevirtualinherited

Defines/Changes the output target and registers for audio change notifications.

Reimplemented in AudioInputMonitor, AudioInputMonitor, EncodedAudioStream, ReformatBaseStream, TimedStream, VolumeMeter, and VolumeMeter.

◆ setOutput() [2/2]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void setOutput ( Print & out )

inlineoverridevirtual

Defines/Changes the output target

Parameters

out	Print stream where processed audio will be written

Implements ModifyingStream.

◆ setStream() [1/2]

virtual void setStream ( AudioStream & io )

inlinevirtualinherited

Defines/Changes the input & output and registers for audio change notifications.

Reimplemented in AudioInputMonitor, AudioInputMonitor, EncodedAudioStream, ReformatBaseStream, TimedStream, VolumeMeter, and VolumeMeter.

◆ setStream() [2/2]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void setStream ( Stream & io )

inlineoverridevirtual

Defines/Changes the input & output stream

Parameters

io	Stream to use for both reading and writing audio data

Implements ModifyingStream.

◆ setupFrequencies()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

void setupFrequencies ( int sampleRate )

inlineprotected

◆ setWriteBufferSize() [1/2]

void setWriteBufferSize ( int size )

inlineinherited

◆ setWriteBufferSize() [2/2]

void setWriteBufferSize ( int size )

inlineinherited

◆ sinc()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float sinc ( float x )

inlineprotected

◆ update()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool update ( )

inline

◆ updateFIRKernel()

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool updateFIRKernel ( )

inlineprotected

◆ write() [1/2]

virtual size_t write ( uint8_t ch )

inlineoverridevirtualinherited

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

◆ write() [2/2]

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

size_t write	(	const uint8_t *	data,
		size_t	len )

inlineoverridevirtual

Reimplemented from AudioStream.

◆ writeSilence() [1/2]

virtual void writeSilence ( size_t len )

inlinevirtualinherited

Writes len bytes of silence (=0).

◆ writeSilence() [2/2]

virtual void writeSilence ( size_t len )

inlinevirtualinherited

Writes len bytes of silence (=0).

Member Data Documentation

◆ _timeout

int _timeout = 10

protectedinherited

◆ activeKernel

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

volatile int16_t* activeKernel

protected

◆ autoUpdate

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

bool autoUpdate = false

protected

◆ centerFreqs

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float centerFreqs[NUM_BANDS]

protected

◆ currentSampleRate

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

int currentSampleRate = 0

protected

◆ filtered

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

FilteredStream<SampleT, SampleT> filtered

protected

◆ fir_vector

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

Vector<EQFIRFilter> fir_vector

protected

Vector of FIR filters for each channel.

◆ gains

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float gains[NUM_BANDS] = {0}

protected

◆ gainsDirty

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

volatile bool gainsDirty = false

protected

◆ info

AudioInfo info

protectedinherited

◆ is_notify_active

bool is_notify_active = true

protectedinherited

◆ isUpdating

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

volatile bool isUpdating = false

protected

◆ kernelA

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

int16_t kernelA[NUM_TAPS]

protected

◆ kernelB

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

int16_t kernelB[NUM_TAPS]

protected

◆ notify_vector

Vector< AudioInfoSupport * > notify_vector

protectedinherited

◆ p_io

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

Stream* p_io = nullptr

protected

Input stream for read operations.

◆ p_out

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

Print* p_out = nullptr

protected

Output stream for write operations.

◆ pendingGains

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float pendingGains[NUM_BANDS] = {0}

protected

◆ Q15_SCALE

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float Q15_SCALE = 32767.0f

staticconstexprprotected

◆ tempFloat

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float tempFloat[NUM_TAPS] = {0}

protected

◆ tmp_in

RingBuffer< uint8_t > tmp_in {0}

protectedinherited

◆ tmp_out

RingBuffer< uint8_t > tmp_out {0}

protectedinherited

◆ updateKernel

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

volatile int16_t* updateKernel

protected

◆ windowCoeffs

template<typename SampleT = int16_t, typename AccT = int64_t, int NUM_TAPS = 128, int NUM_BANDS = 12>

float windowCoeffs[NUM_TAPS]

protected

◆ write_buffer_size

int write_buffer_size = 8

protectedinherited

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

src/AudioTools/Sandbox/EqualizerNBands.h

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ EqualizerNBands() [1/5]

◆ EqualizerNBands() [2/5]

◆ EqualizerNBands() [3/5]

◆ EqualizerNBands() [4/5]

◆ EqualizerNBands() [5/5]

◆ ~EqualizerNBands()

Member Function Documentation

◆ addNotifyAudioChange() [1/2]

◆ addNotifyAudioChange() [2/2]

◆ audioInfo() [1/2]

◆ audioInfo() [2/2]

◆ audioInfoOut() [1/2]

◆ audioInfoOut() [2/2]

◆ available() [1/2]

◆ available() [2/2]

◆ availableForWrite() [1/2]

◆ availableForWrite() [2/2]

◆ begin() [1/2]

◆ begin() [2/2]

◆ clearNotifyAudioChange() [1/2]

◆ clearNotifyAudioChange() [2/2]

◆ end()

◆ enterCritical()

◆ exitCritical()

◆ flush()

◆ getBandCount()

◆ getBandDB()

◆ getBandFrequency()

◆ getBandGain()

◆ initializeKernel()

◆ isNotifyActive() [1/2]

◆ isNotifyActive() [2/2]

◆ map()

◆ maybeUpdateKernel()

◆ not_supported() [1/2]

◆ not_supported() [2/2]

◆ notifyAudioChange() [1/2]

◆ notifyAudioChange() [2/2]

◆ operator bool() [1/2]

◆ operator bool() [2/2]

◆ preCalculateWindow()

◆ readBytes()

◆ readSilence() [1/2]

◆ readSilence() [2/2]

◆ refillReadBuffer() [1/2]

◆ refillReadBuffer() [2/2]

◆ removeNotifyAudioChange() [1/2]

◆ removeNotifyAudioChange() [2/2]

◆ setAudioInfo() [1/2]

◆ setAudioInfo() [2/2]

◆ setAutoUpdate()

◆ setBandDB()

◆ setBandGain()

◆ setBandGains()

◆ setNotifyActive() [1/2]

◆ setNotifyActive() [2/2]

◆ setOutput() [1/2]

◆ setOutput() [2/2]

◆ setStream() [1/2]

◆ setStream() [2/2]

◆ setupFrequencies()

◆ setWriteBufferSize() [1/2]

◆ setWriteBufferSize() [2/2]

◆ sinc()

◆ update()

◆ updateFIRKernel()

◆ write() [1/2]

◆ write() [2/2]

◆ writeSilence() [1/2]

◆ writeSilence() [2/2]

Member Data Documentation

◆ _timeout

◆ activeKernel