OpalSilenceDetector Class Reference

#include <silencedetect.h>

Inheritance diagram for OpalSilenceDetector:

Data Structures
struct	Params

Public Types
typedef Modes	Mode

Public Member Functions
	P_DECLARE_STREAMABLE_ENUM (Modes, NoSilenceDetection, FixedSilenceDetection, AdaptiveSilenceDetection)
Construction
	OpalSilenceDetector (const Params &newParam)

Basic operations
PNotifier	receiveHandler
Mode	mode
unsigned	signalDeadband
unsigned	silenceDeadband
unsigned	adaptivePeriod
unsigned	clockRate
unsigned	lastTimestamp
unsigned	receivedTime
unsigned	levelThreshold
unsigned	signalMinimum
unsigned	silenceMaximum
unsigned	signalReceivedTime
unsigned	silenceReceivedTime
bool	inTalkBurst
PMutex	inUse
const PNotifier &	GetReceiveHandler () const
void	SetParameters (const Params &params, const int clockRate=0)
void	GetParameters (Params &params)
void	SetClockRate (unsigned clockRate)
unsigned	GetClockRate () const
Mode	GetStatus (PBoolean *isInTalkBurst, unsigned *currentThreshold) const
virtual unsigned	GetAverageSignalLevel (const BYTE *buffer, PINDEX size)=0
	PDECLARE_NOTIFIER (RTP_DataFrame, OpalSilenceDetector, ReceivedPacket)

Member Typedef Documentation

typedef Modes OpalSilenceDetector::Mode

Constructor & Destructor Documentation

OpalSilenceDetector::OpalSilenceDetector

(

const Params &

newParam

)

Create a new detector. Default clock rate is 8000.

Parameters

newParam

New parameters for silence detector

Member Function Documentation

virtual unsigned OpalSilenceDetector::GetAverageSignalLevel ( const BYTE *  buffer, PINDEX  size  )

pure virtual

Get the average signal level in the stream. This is called from within the silence detection algorithm to calculate the average signal level of the last data frame read from the stream.

The default behaviour returns UINT_MAX which indicates that the average signal has no meaning for the stream.

Parameters

buffer	RTP payload being detected
size	Size of payload buffer

Implemented in OpalLineSilenceDetector, and OpalPCM16SilenceDetector.

unsigned OpalSilenceDetector::GetClockRate ( ) const

inline

Get the current sampling clock rate.

References clockRate.

void OpalSilenceDetector::GetParameters

(

Params &

params

)

Get the current parameters in use.

const PNotifier& OpalSilenceDetector::GetReceiveHandler ( ) const

inline

References receiveHandler.

Mode OpalSilenceDetector::GetStatus	(	PBoolean *	isInTalkBurst,
		unsigned *	currentThreshold
	)		const

Get silence detection status

The inTalkBurst value is true if packet transmission is enabled and false if it is being suppressed due to silence.

The currentThreshold value is the value from 0 to 32767 which is used as the threshold value for 16 bit PCM data.

OpalSilenceDetector::P_DECLARE_STREAMABLE_ENUM	(	Modes	,
		NoSilenceDetection	,
		FixedSilenceDetection	,
		AdaptiveSilenceDetection
	)

OpalSilenceDetector::PDECLARE_NOTIFIER ( RTP_DataFrame  , OpalSilenceDetector  , ReceivedPacket    )

protected

void OpalSilenceDetector::SetClockRate

(

unsigned

clockRate

)

Set the sampling clock rate for the preprocessor. Adusts the interpretation of time values. This may be called while audio is being transferred, but if in adaptive mode calling this will reset the filter.

Parameters

clockRate

Sampling clock rate for the preprocessor

void OpalSilenceDetector::SetParameters	(	const Params &	params,
		const int	clockRate = 0
	)

Set the silence detector parameters. This adjusts the silence detector "agression". The deadband and adaptive periods are in ms units to work for any clock rate. The clock rate value is optional: 0 leaves value unchanged. This may be called while audio is being transferred, but if in adaptive mode calling this will reset the filter.

Parameters

params	New parameters for silence detector
clockRate	Sampling clock rate for the preprocessor

Field Documentation

unsigned OpalSilenceDetector::adaptivePeriod

protected

unsigned OpalSilenceDetector::clockRate

protected

Referenced by GetClockRate().

bool OpalSilenceDetector::inTalkBurst

protected

PMutex OpalSilenceDetector::inUse

protected

unsigned OpalSilenceDetector::lastTimestamp

protected

unsigned OpalSilenceDetector::levelThreshold

protected

Mode OpalSilenceDetector::mode

protected

unsigned OpalSilenceDetector::receivedTime

protected

PNotifier OpalSilenceDetector::receiveHandler

protected

Referenced by GetReceiveHandler().

unsigned OpalSilenceDetector::signalDeadband

protected

unsigned OpalSilenceDetector::signalMinimum

protected

unsigned OpalSilenceDetector::signalReceivedTime

protected

unsigned OpalSilenceDetector::silenceDeadband

protected

unsigned OpalSilenceDetector::silenceMaximum

protected

unsigned OpalSilenceDetector::silenceReceivedTime

protected

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

• silencedetect.h