An Audio Stream backed by a buffer (queue) which tries to correct jitter and automatically adjusts for the slightly different clock rates between an audio source and audio target. Use separate tasks to write and read the data. Also make sure that you protect the access with a mutex or provide a thread-safe buffer! More...

#include <AdaptiveResamplingStream.h>

Inheritance diagram for AdaptiveResamplingStream:

Public Member Functions
	AdaptiveResamplingStream (BaseBuffer< uint8_t > &buffer, float stepRangePercent=5.0f)
	Construct a new AdaptiveResamplingStream object.

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 ()

virtual int	available () override

virtual int	availableForWrite () override

bool	begin ()
	Initialize the stream and internal components.

virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.

void	end ()
	End the stream and release resources.

virtual void	flush () override

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

float	levelPercent ()
	Get the fill level at the last calculation in percent.

float	levelPercentActual ()
	Get the current actual buffer fill level in percent.

virtual	operator bool ()

size_t	readBytes (uint8_t *data, size_t len) override
	Read resampled audio data from the buffer.

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

float	recalculate ()
	Recalculate the resampling step size based on buffer fill level.

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.

void	setKalmanParameters (float process_noise, float measurement_noise)
	Set the Kalman filter parameters.

void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active)

void	setPIDParameters (float p_value, float i_value, float d_value)
	Set the PID controller parameters.

void	setStepRangePercent (float rangePercent)
	Set the allowed resampling range as a percent.

void	setWriteBufferSize (int size)

size_t	write (const uint8_t *data, size_t len) override
	Write audio data to the buffer.

virtual size_t	write (uint8_t ch) override

virtual void	writeSilence (size_t len)
	Writes len bytes of silence (=0).

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

void	notifyAudioChange (AudioInfo info)

void	refillReadBuffer ()

Protected Attributes
int	_timeout = 10

float	d = 0.0001

float	i = 0.00005

AudioInfo	info

bool	is_notify_active = true

KalmanFilter	kalman_filter {0.01f, 0.1f}

float	level_percent = 0.0

Vector< AudioInfoSupport * >	notify_vector

float	p = 0.005

BaseBuffer< uint8_t > *	p_buffer = nullptr

PIDController	pid

QueueStream< uint8_t >	queue_stream

uint32_t	read_count = 0

float	resample_range = 0

ResampleStream	resample_stream

float	step_size = 1.0

RingBuffer< uint8_t >	tmp_in {0}

RingBuffer< uint8_t >	tmp_out {0}

int	write_buffer_size = MAX_SINGLE_CHARS

Detailed Description

An Audio Stream backed by a buffer (queue) which tries to correct jitter and automatically adjusts for the slightly different clock rates between an audio source and audio target. Use separate tasks to write and read the data. Also make sure that you protect the access with a mutex or provide a thread-safe buffer!

The resamping step size is calculated with the help of a PID controller. The fill level is smoothed using a Kalman filter.

Author: Phil Schatzmann

Constructor & Destructor Documentation

◆ AdaptiveResamplingStream()

AdaptiveResamplingStream	(	BaseBuffer< uint8_t > &	buffer,
		float	stepRangePercent = `5.0f`
	)

inline

Construct a new AdaptiveResamplingStream object.

Parameters

buffer	Reference to the buffer used for audio data
stepRangePercent	Allowed resampling range in percent (default: 0.05)

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()

virtual int available ( )

inlineoverridevirtualinherited

◆ availableForWrite()

virtual int availableForWrite ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in UDPStream, AudioFFTBase, I2SCodecStream, A2DPStream, AbstractURLStream, URLStreamESP32, Equalizer3Bands, Equalizer3BandsPerChannel, I2SStream, MeasuringStream, ProgressStream, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, and VolumeStream.

◆ begin()

bool begin ( )

inlinevirtual

Initialize the stream and internal components.

Returns: true if initialization was successful, false otherwise

Reimplemented from BaseStream.

◆ clearNotifyAudioChange()

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

◆ end()

void end ( )

inlinevirtual

End the stream and release resources.

Reimplemented from BaseStream.

◆ flush()

virtual void flush ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in ResampleStream, BufferedTaskStream, and BufferedStream.

◆ levelPercent()

float levelPercent ( )

inline

Get the fill level at the last calculation in percent.

Returns: float Last calculated fill level (0-100)

◆ levelPercentActual()

float levelPercentActual ( )

inline

Get the current actual buffer fill level in percent.

Returns: float Current fill level (0-100)

◆ operator bool()

virtual operator bool ( )

inlinevirtualinherited

Reimplemented in A2DPStream, ICYStreamT< T >, I2SStream, MemoryStream, and Pipeline.

◆ readBytes()

size_t readBytes	(	uint8_t *	data,
		size_t	len
	)

inlineoverridevirtual

Read resampled audio data from the buffer.

Parameters

data	Pointer to the buffer to fill
len	Number of bytes to read

Returns: size_t Number of bytes actually read

Reimplemented from AudioStream.

◆ recalculate()

float recalculate ( )

inline

Recalculate the resampling step size based on buffer fill level.

Returns: float The new step size

◆ removeNotifyAudioChange()

virtual bool removeNotifyAudioChange ( AudioInfoSupport & bi )

inlinevirtualinherited

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

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

◆ setAudioInfo()

virtual void setAudioInfo ( AudioInfo info )

inlineoverridevirtualinherited

Defines the input AudioInfo.

Implements AudioInfoSupport.

Reimplemented in VS1053Stream, WM8960Stream, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, VolumeStream, MiniAudioStream, PortAudioStream, I2SCodecStream, MozziStream, SPDIFOutput, AudioLoRa, AnalogAudioStream, I2SStream, TimerCallbackAudioStream, AudioBLEStream, LoRaStream, AudioFFTBase, AudioKitStream, VBANStream, AnalogAudioArduino, Equalizer3Bands, Equalizer3BandsPerChannel, AdapterAudioOutputToAudioStream, TimedStream, MeasuringStream, ProgressStream, CallbackStream, VolumeMeter, AudioInputMonitor, FormatConverterStream, FadeStream, GoertzelStream, Pipeline::ModifyingStreamAdapter, EncodedAudioStream, PureDataStream, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, Pipeline, ResampleStream, and ResampleStreamT< TInterpolator >.

◆ setKalmanParameters()

void setKalmanParameters	(	float	process_noise,
		float	measurement_noise
	)

inline

Set the Kalman filter parameters.

Parameters

process_noise	Process noise covariance (Q)
measurement_noise	Measurement noise covariance (R)

◆ setPIDParameters()

void setPIDParameters	(	float	p_value,
		float	i_value,
		float	d_value
	)

inline

Set the PID controller parameters.

Parameters

p_value	Proportional gain
i_value	Integral gain
d_value	Derivative gain

◆ setStepRangePercent()

void setStepRangePercent ( float rangePercent )

inline

Set the allowed resampling range as a percent.

Parameters

rangePercent Allowed range in percent (e.g., 5.0 for ± 5%)

◆ write() [1/2]

size_t write	(	const uint8_t *	data,
		size_t	len
	)

inlineoverridevirtual

Write audio data to the buffer.

Parameters

data	Pointer to the data to write
len	Number of bytes to write

Returns: size_t Number of bytes actually written

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/Communication/AdaptiveResamplingStream.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ AdaptiveResamplingStream()

Member Function Documentation

◆ addNotifyAudioChange()

◆ audioInfo()

◆ audioInfoOut()

◆ available()

◆ availableForWrite()

◆ begin()

◆ clearNotifyAudioChange()

◆ end()

◆ flush()

◆ levelPercent()

◆ levelPercentActual()

◆ operator bool()

◆ readBytes()

◆ recalculate()

◆ removeNotifyAudioChange()

◆ setAudioInfo()

◆ setKalmanParameters()

◆ setPIDParameters()

◆ setStepRangePercent()

◆ write() [1/2]

◆ write() [2/2]