OpalJitterBuffer Class Reference

#include <jitter.h>

Inheritance diagram for OpalJitterBuffer:

Public Member Functions
Construction
	OpalJitterBuffer (unsigned minJitterDelay, unsigned maxJitterDelay, unsigned timeUnits=8, PINDEX packetSize=2048)
virtual	~OpalJitterBuffer ()
Overrides from PObject
void	PrintOn (ostream &strm) const
Operations
void	SetDelay (unsigned minJitterDelay, unsigned maxJitterDelay, PINDEX packetSize=2048)
void	Reset ()
virtual PBoolean	WriteData (const RTP_DataFrame &frame, const PTimeInterval &tick=0)
virtual PBoolean	ReadData (RTP_DataFrame &frame, const PTimeInterval &tick=0)
DWORD	GetCurrentJitterDelay () const
DWORD	GetMinJitterDelay () const
DWORD	GetMaxJitterDelay () const
unsigned	GetTimeUnits () const
DWORD	GetPacketsTooLate () const
DWORD	GetBufferOverruns () const
DWORD	GetMaxConsecutiveMarkerBits () const
void	SetMaxConsecutiveMarkerBits (DWORD max)
Protected Types
enum	{ e_SynchronisationStart, e_SynchronisationFill, e_SynchronisationShrink, e_SynchronisationDone }
typedef std::map< DWORD, RTP_DataFrame >	FrameMap
Protected Member Functions
DWORD	CalculateRequiredTimestamp (DWORD playOutTimestamp) const
bool	AdjustCurrentJitterDelay (int delta)
Protected Attributes
unsigned	m_timeUnits
PINDEX	m_packetSize
DWORD	m_minJitterDelay
	Minimum jitter delay in timestamp units.
DWORD	m_maxJitterDelay
	Maximum jitter delay in timestamp units.
int	m_jitterGrowTime
	Amaint to increase jitter delay by when get "late" packet.
DWORD	m_jitterShrinkPeriod
int	m_jitterShrinkTime
	Amount to shrink jitter delay by if consistently filled.
DWORD	m_silenceShrinkPeriod
	Reduce jitter delay is silent for this long.
int	m_silenceShrinkTime
	Amount to shrink jitter delay by if consistently silent.
DWORD	m_jitterDriftPeriod
int	m_currentJitterDelay
DWORD	m_packetsTooLate
DWORD	m_bufferOverruns
DWORD	m_consecutiveMarkerBits
DWORD	m_maxConsecutiveMarkerBits
DWORD	m_consecutiveLatePackets
DWORD	m_averageFrameTime
DWORD	m_lastTimestamp
DWORD	m_bufferFilledTime
DWORD	m_bufferLowTime
DWORD	m_bufferEmptiedTime
int	m_timestampDelta
enum OpalJitterBuffer:: { ... }	m_synchronisationState
FrameMap	m_frames
PMutex	m_bufferMutex
RTP_JitterBufferAnalyser *	m_analyser

---

Detailed Description

This is an Abstract jitter buffer, which can be used simply in any application. The user is required to use a descendant of this class, and provide a "OnReadPacket" method, so that network packets can be placed in this class instance

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Member Typedef Documentation

typedef std::map<DWORD, RTP_DataFrame> OpalJitterBuffer::FrameMap [protected]

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Member Enumeration Documentation

anonymous enum [protected]

Enumerator:

e_SynchronisationStart
e_SynchronisationFill
e_SynchronisationShrink
e_SynchronisationDone

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Constructor & Destructor Documentation

OpalJitterBuffer::OpalJitterBuffer	(	unsigned	minJitterDelay,
		unsigned	maxJitterDelay,
		unsigned	timeUnits = 8,
		PINDEX	packetSize = 2048
	)

Constructor for this jitter buffer. The size of this buffer can be altered later with the SetDelay method

Parameters:

minJitterDelay	Minimum delay in RTP timestamp units
maxJitterDelay	Maximum delay in RTP timestamp units
timeUnits	Time units, usually 8 or 16
packetSize	Max RTP packet size

virtual OpalJitterBuffer::~OpalJitterBuffer

(

)

[virtual]

Destructor, which closes this down and deletes the internal list of frames

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Member Function Documentation

bool OpalJitterBuffer::AdjustCurrentJitterDelay

(

int

delta

)

[protected]

DWORD OpalJitterBuffer::CalculateRequiredTimestamp

(

DWORD

playOutTimestamp

)

const [protected]

DWORD OpalJitterBuffer::GetBufferOverruns

(

)

const [inline]

Get total number received packets that overran the jitter buffer.

References m_bufferOverruns.

DWORD OpalJitterBuffer::GetCurrentJitterDelay

(

)

const [inline]

Get current delay for jitter buffer.

References m_currentJitterDelay.

DWORD OpalJitterBuffer::GetMaxConsecutiveMarkerBits

(

)

const [inline]

Get maximum consecutive marker bits before buffer starts to ignore them.

References m_maxConsecutiveMarkerBits.

DWORD OpalJitterBuffer::GetMaxJitterDelay

(

)

const [inline]

Get maximum delay for jitter buffer.

References m_maxJitterDelay.

DWORD OpalJitterBuffer::GetMinJitterDelay

(

)

const [inline]

Get minimum delay for jitter buffer.

References m_minJitterDelay.

DWORD OpalJitterBuffer::GetPacketsTooLate

(

)

const [inline]

Get total number received packets too late to go into jitter buffer.

References m_packetsTooLate.

unsigned OpalJitterBuffer::GetTimeUnits

(

)

const [inline]

Get time units.

References m_timeUnits.

void OpalJitterBuffer::PrintOn

(

ostream &

strm

)

const

Report the statistics for this jitter instance

virtual PBoolean OpalJitterBuffer::ReadData	(	RTP_DataFrame &	frame,
		const PTimeInterval &	tick = 0
	)		[virtual]

Read a data frame from the jitter buffer. This function never blocks. If no data is available, an RTP packet with zero payload size is returned.

Parameters:

frame	Frame to extract from jitter buffer
tick	Real time tick for packet removal

void OpalJitterBuffer::Reset

(

)

Reset jitter buffer.

void OpalJitterBuffer::SetDelay	(	unsigned	minJitterDelay,
		unsigned	maxJitterDelay,
		PINDEX	packetSize = 2048
	)

Set the maximum delay the jitter buffer will operate to.

Parameters:

minJitterDelay	Minimum delay in RTP timestamp units
maxJitterDelay	Maximum delay in RTP timestamp units
packetSize	Max RTP packet size

void OpalJitterBuffer::SetMaxConsecutiveMarkerBits

(

DWORD

max

)

[inline]

Set maximum consecutive marker bits before buffer starts to ignore them.

References m_maxConsecutiveMarkerBits.

virtual PBoolean OpalJitterBuffer::WriteData	(	const RTP_DataFrame &	frame,
		const PTimeInterval &	tick = 0
	)		[virtual]

Write data frame from the RTP channel.

Parameters:

frame	Frame to feed into jitter buffer
tick	Real time tick for packet arrival

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Field Documentation

RTP_JitterBufferAnalyser* OpalJitterBuffer::m_analyser [protected]

DWORD OpalJitterBuffer::m_averageFrameTime [protected]

DWORD OpalJitterBuffer::m_bufferEmptiedTime [protected]

DWORD OpalJitterBuffer::m_bufferFilledTime [protected]

DWORD OpalJitterBuffer::m_bufferLowTime [protected]

PMutex OpalJitterBuffer::m_bufferMutex [protected]

DWORD OpalJitterBuffer::m_bufferOverruns [protected]

Referenced by GetBufferOverruns().

DWORD OpalJitterBuffer::m_consecutiveLatePackets [protected]

DWORD OpalJitterBuffer::m_consecutiveMarkerBits [protected]

int OpalJitterBuffer::m_currentJitterDelay [protected]

Referenced by GetCurrentJitterDelay().

FrameMap OpalJitterBuffer::m_frames [protected]

DWORD OpalJitterBuffer::m_jitterDriftPeriod [protected]

int OpalJitterBuffer::m_jitterGrowTime [protected]

Amaint to increase jitter delay by when get "late" packet.

DWORD OpalJitterBuffer::m_jitterShrinkPeriod [protected]

Period (in timestamp units) over which buffer is consistently filled before shrinking

int OpalJitterBuffer::m_jitterShrinkTime [protected]

Amount to shrink jitter delay by if consistently filled.

DWORD OpalJitterBuffer::m_lastTimestamp [protected]

DWORD OpalJitterBuffer::m_maxConsecutiveMarkerBits [protected]

Referenced by GetMaxConsecutiveMarkerBits(), and SetMaxConsecutiveMarkerBits().

DWORD OpalJitterBuffer::m_maxJitterDelay [protected]

Maximum jitter delay in timestamp units.

Referenced by GetMaxJitterDelay().

DWORD OpalJitterBuffer::m_minJitterDelay [protected]

Minimum jitter delay in timestamp units.

Referenced by GetMinJitterDelay().

PINDEX OpalJitterBuffer::m_packetSize [protected]

DWORD OpalJitterBuffer::m_packetsTooLate [protected]

Referenced by GetPacketsTooLate().

DWORD OpalJitterBuffer::m_silenceShrinkPeriod [protected]

Reduce jitter delay is silent for this long.

int OpalJitterBuffer::m_silenceShrinkTime [protected]

Amount to shrink jitter delay by if consistently silent.

enum { ... } OpalJitterBuffer::m_synchronisationState [protected]

int OpalJitterBuffer::m_timestampDelta [protected]

unsigned OpalJitterBuffer::m_timeUnits [protected]

Referenced by GetTimeUnits().

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

• jitter.h