AdaptiveResamplingStream Class Reference

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 ()
	Construct a new AdaptiveResamplingStream object You need to call setBuffer() and setStepRangePercent() before begin()
	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.
bool	isPrimed ()
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	setBuffer (BaseBuffer< uint8_t > &buffer)
	Set the buffer used for audio data.
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	setStartFillPercent (float percent)
	Defines the fill level (percent) that must be reached once, right after begin(), before any data is returned by readBytes(). Defaults to 50%; 0 disables priming. See AdaptiveResamplingBuffer::setStartFillPercent().
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 ()
	Refill small read buffer (e.g. 8 bytes) to avoid single byte reads when calling read()

Protected Attributes
int	_timeout = 10
AudioInfo	info
bool	is_notify_active = true
Vector< AudioInfoSupport * >	notify_vector
AdaptiveResamplingBuffer	resampling_buffer
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!

This is a thin Stream adapter around AdaptiveResamplingBuffer, which implements the actual jitter-buffering/resampling logic behind the BaseBuffer<uint8_t> API. If you need a BaseBuffer (e.g. to plug into an API that expects one) rather than a Stream, use AdaptiveResamplingBuffer directly.

Author

Phil Schatzmann

Constructor & Destructor Documentation

AdaptiveResamplingStream() [1/2]

AdaptiveResamplingStream ( )

inline

Construct a new AdaptiveResamplingStream object You need to call setBuffer() and setStepRangePercent() before begin()

AdaptiveResamplingStream() [2/2]

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

available()

virtual int available ( )

inlineoverridevirtualinherited

Reimplemented from Stream.

Reimplemented in AudioKitStream, AudioLoRa, URLStreamBufferedT< T >, URLStreamBufferedT< ICYStream >, VBANStream, AudioStreamWrapper, FaustStream< DSP >, AudioMP34DT05, I2SCodecStream, MiniAudioStream, StdioStream, TfLiteAudioStream, A2DPStream, ESPNowStream, HammingFEC< bytecount, block_t >, HLSStreamT< URLStream >, HttpRequest, ICYStreamT< T >, URLStream, BufferedTaskStream, NRF24Stream, ReedSolomonFEC< bytecount, additional_bytes >, SPIAudioSlave, UDPStream, USBAudioDeviceBase, AnalogAudioStream, AudioEffectStreamT< T >, AudioEffectStream, Equalizer3Bands, Equalizer3BandsPerChannel, I2SStream, ReformatBaseStream, TimedStream, MemoryStream, RingBufferStream, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, BufferedStream, ConverterStream< T >, MeasuringStream, ProgressStream, Throttle, InputMerge< T >, CallbackStream, FilteredStream< T, TF >, FilteredStream< int16_t, int16_t >, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, CatStream, QueueStream< T >, QueueStream< uint8_t >, DynamicMemoryStream, FadeStream, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, Pipeline, Pipeline::ModifyingStreamAdapter, QualityAnalysisStream, VolumeStream, FileLoopT< FileType >, FileLoopT< File >, AudioFFTBase, AudioBLEClient, AudioBLEClient, AudioBLEServer, and AudioBLEServer.

availableForWrite()

virtual int availableForWrite ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in AudioLoRa, UDPStream, VBANStream, AudioStreamWrapper, ConverterStream< T >, EncodedAudioStream, FaustStream< DSP >, I2SCodecStream, MiniAudioStream, StdioStream, A2DPStream, ESPNowStream, HammingFEC< bytecount, block_t >, AbstractURLStream, URLStreamESP32, NRF24Stream, ReedSolomonFEC< bytecount, additional_bytes >, SPIAudioSlave, USBAudioDeviceBase, AnalogAudioStream, AudioEffectStreamT< T >, AudioEffectStream, Equalizer3Bands, Equalizer3BandsPerChannel, I2SStream, ReformatBaseStream, TimedStream, MemoryStream, RingBufferStream, MeasuringStream, ProgressStream, Throttle, FilteredStream< T, TF >, FilteredStream< int16_t, int16_t >, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, QueueStream< T >, QueueStream< uint8_t >, DynamicMemoryStream, FadeStream, FrequencyDetectorAutoCorrelation, FrequencyDetectorZeroCrossing, Pipeline, QualityAnalysisStream, VolumeStream, AudioFFTBase, AudioBLEClient, AudioBLEClient, AudioBLEServer, and AudioBLEServer.

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

isNotifyActive()

bool isNotifyActive ( )

inlineinherited

Checks if the automatic AudioInfo update is active.

isPrimed()

bool isPrimed ( )

inline

True once the buffer has reached setStartFillPercent() (or always true if priming is disabled).

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)

not_supported()

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

inlineprotectedvirtualinherited

notifyAudioChange()

void notifyAudioChange ( AudioInfo  info )

inlineprotectedinherited

operator bool()

virtual operator bool ( )

inlinevirtualinherited

Reimplemented in A2DPStream, ICYStreamT< T >, AudioBLEStream, PortAudioStream, URLStream, USBAudioDeviceBase, I2SStream, AdapterAudioOutputToAudioStream, TimedStream, MemoryStream, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, Pipeline, and AudioFFTBase.

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.

readSilence()

virtual size_t readSilence ( uint8_t *  buffer, size_t  length  )

inlinevirtualinherited

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

recalculate()

float recalculate ( )

inline

Recalculate the resampling step size based on buffer fill level.

Returns

float The new step size

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 >.

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, MDFEchoCancellationStream< T, SampleType >, AudioKitStream, NRF24Stream, SPIAudioSlave, USBAudioDeviceBase, VBANStream, Equalizer3Bands, Equalizer3BandsPerChannel, AdapterAudioOutputToAudioStream, TimedStream, MeasuringStream, ProgressStream, CallbackStream, VolumeMeter, AudioInputMonitor, FormatConverterStream, FadeStream, GoertzelStream, Pipeline::ModifyingStreamAdapter, QualityAnalysisStream, AudioFFTBase, EncodedAudioStream, PureDataStream, GeneratedSoundStream< T >, GeneratedSoundStream< int16_t >, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, Pipeline, ResampleStream, and ResampleStreamT< TInterpolator >.

setBuffer()

void setBuffer ( BaseBuffer< uint8_t > &  buffer )

inline

Set the buffer used for audio data.

Parameters

buffer

Reference to the buffer used for audio data

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)

setNotifyActive()

void setNotifyActive ( bool  flag )

inlineinherited

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

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

setStartFillPercent()

void setStartFillPercent ( float  percent )

inline

Defines the fill level (percent) that must be reached once, right after begin(), before any data is returned by readBytes(). Defaults to 50%; 0 disables priming. See AdaptiveResamplingBuffer::setStartFillPercent().

Parameters

percent

Fill level in percent (e.g. 50.0 for 50%)

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%)

setWriteBufferSize()

void setWriteBufferSize ( int  size )

inlineinherited

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

writeSilence()

virtual void writeSilence ( size_t  len )

inlinevirtualinherited

Writes len bytes of silence (=0).

Member Data Documentation

_timeout

int _timeout = 10

protectedinherited

info

AudioInfo info

protectedinherited

is_notify_active

bool is_notify_active = true

protectedinherited

notify_vector

Vector<AudioInfoSupport*> notify_vector

protectedinherited

resampling_buffer

AdaptiveResamplingBuffer resampling_buffer

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/Communication/AdaptiveResamplingStream.h