OPAL Version 3.10.2
OpalJitterBuffer Class Reference

#include <jitter.h>

Inheritance diagram for OpalJitterBuffer:
OpalJitterBufferThread RTP_JitterBuffer

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


Member Typedef Documentation

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

Member Enumeration Documentation

anonymous enum [protected]
Enumerator:
e_SynchronisationStart 
e_SynchronisationFill 
e_SynchronisationShrink 
e_SynchronisationDone 

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:
minJitterDelayMinimum delay in RTP timestamp units
maxJitterDelayMaximum delay in RTP timestamp units
timeUnitsTime units, usually 8 or 16
packetSizeMax RTP packet size
virtual OpalJitterBuffer::~OpalJitterBuffer ( ) [virtual]

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


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:
frameFrame to extract from jitter buffer
tickReal 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:
minJitterDelayMinimum delay in RTP timestamp units
maxJitterDelayMaximum delay in RTP timestamp units
packetSizeMax 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:
frameFrame to feed into jitter buffer
tickReal time tick for packet arrival

Field Documentation

RTP_JitterBufferAnalyser* OpalJitterBuffer::m_analyser [protected]
PMutex OpalJitterBuffer::m_bufferMutex [protected]

Referenced by GetBufferOverruns().

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

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

Amount to shrink jitter delay by if consistently filled.

Maximum jitter delay in timestamp units.

Referenced by GetMaxJitterDelay().

Minimum jitter delay in timestamp units.

Referenced by GetMinJitterDelay().

PINDEX OpalJitterBuffer::m_packetSize [protected]

Referenced by GetPacketsTooLate().

Reduce jitter delay is silent for this long.

Amount to shrink jitter delay by if consistently silent.

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

Referenced by GetTimeUnits().


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