OPAL  Version 3.10.4
OpalMediaStream Class Reference

#include <mediastrm.h>

Inheritance diagram for OpalMediaStream:
OpalH224MediaStream OpalIAX2MediaStream OpalIMMediaStream OpalLineMediaStream OpalLocalMediaStream OpalMixerMediaStream OpalNullMediaStream OpalRawMediaStream OpalRTPMediaStream OpalUDPMediaStream OpalVideoMediaStream

Public Member Functions

Overrides from PObject
void PrintOn (ostream &strm) const
Operations
virtual OpalMediaFormat GetMediaFormat () const
bool UpdateMediaFormat (const OpalMediaFormat &mediaFormat)
virtual bool InternalUpdateMediaFormat (const OpalMediaFormat &mediaFormat)
virtual PBoolean ExecuteCommand (const OpalMediaCommand &command)
virtual PBoolean Open ()
virtual PBoolean Start ()
virtual PBoolean Close ()
virtual void OnStartMediaPatch ()
virtual void OnStopMediaPatch (OpalMediaPatch &patch)
virtual PBoolean WritePackets (RTP_DataFrameList &packets)
virtual PBoolean ReadPacket (RTP_DataFrame &packet)
virtual PBoolean WritePacket (RTP_DataFrame &packet)
virtual PBoolean ReadData (BYTE *data, PINDEX size, PINDEX &length)
virtual PBoolean WriteData (const BYTE *data, PINDEX length, PINDEX &written)
bool PushPacket (RTP_DataFrame &packet)
virtual PBoolean SetDataSize (PINDEX dataSize, PINDEX frameTime)
PINDEX GetDataSize () const
virtual PBoolean IsSynchronous () const =0
virtual PBoolean RequiresPatchThread (OpalMediaStream *stream) const
virtual PBoolean RequiresPatchThread () const
virtual bool EnableJitterBuffer (bool enab=true) const
Member variable access
OpalConnectionGetConnection () const
bool IsSource () const
bool IsSink () const
unsigned GetSessionID () const
void SetSessionID (unsigned id)
PString GetID () const
unsigned GetTimestamp () const
void SetTimestamp (unsigned ts)
bool GetMarker () const
void SetMarker (bool m)
bool IsPaused () const
virtual bool SetPaused (bool pause, bool fromPatch=false)
bool IsOpen () const
virtual PBoolean SetPatch (OpalMediaPatch *patch)
OpalMediaPatchGetPatch () const
void AddFilter (const PNotifier &filter, const OpalMediaFormat &stage=OpalMediaFormat()) const
bool RemoveFilter (const PNotifier &filter, const OpalMediaFormat &stage=OpalMediaFormat()) const
virtual void GetStatistics (OpalMediaStatistics &statistics, bool fromPatch=false) const

Protected Member Functions

void IncrementTimestamp (PINDEX size)
bool InternalWriteData (const BYTE *data, PINDEX length, PINDEX &written)

Protected Attributes

OpalConnectionconnection
unsigned sessionID
PString identifier
OpalMediaFormat mediaFormat
bool m_paused
bool isSource
bool isOpen
PINDEX defaultDataSize
unsigned timestamp
bool marker
unsigned mismatchedPayloadTypes
OpalMediaPatchmediaPatch
RTP_DataFrame::PayloadTypes m_payloadType
unsigned m_frameTime
PINDEX m_frameSize

Construction

 OpalMediaStream (OpalConnection &conn, const OpalMediaFormat &mediaFormat, unsigned sessionID, bool isSource)
 ~OpalMediaStream ()

Detailed Description

This class describes a media stream as used in the OPAL system. A media stream is the channel through which media data is trasferred between OPAL entities. For example, data being sent to an RTP session over a network would be through a media stream.


Constructor & Destructor Documentation

OpalMediaStream::OpalMediaStream ( OpalConnection conn,
const OpalMediaFormat mediaFormat,
unsigned  sessionID,
bool  isSource 
)
protected

Construct a new media stream.

Parameters:
connConnection that owns the stream
mediaFormatMedia format for stream
sessionIDSession number for stream
isSourceIs a source stream
OpalMediaStream::~OpalMediaStream ( )

Destroy the media stream. Make sure the patch, if present, has been stopped and deleted.


Member Function Documentation

void OpalMediaStream::AddFilter ( const PNotifier &  filter,
const OpalMediaFormat stage = OpalMediaFormat() 
) const

Add a filter to the owning patch safely.

Parameters:
filterFilter notifier to be called.
stageStage in codec pipeline to call filter
virtual PBoolean OpalMediaStream::Close ( )
virtual
virtual bool OpalMediaStream::EnableJitterBuffer ( bool  enab = true) const
virtual

Enable jitter buffer for the media stream. Returns true if a jitter buffer is enabled/disabled. Returns false if no jitter buffer exists for the media stream.

The default behaviour does nothing and returns false.

Reimplemented in OpalMixerMediaStream, and OpalRTPMediaStream.

virtual PBoolean OpalMediaStream::ExecuteCommand ( const OpalMediaCommand command)
virtual

Execute the command specified to the transcoder. The commands are highly context sensitive, for example OpalVideoUpdatePicture would only apply to a video transcoder.

The default behaviour passes the command on to the OpalMediaPatch.

Returns:
true if command is handled.
Parameters:
commandCommand to execute.
OpalConnection& OpalMediaStream::GetConnection ( ) const
inline

Get the owner connection.

References connection.

PINDEX OpalMediaStream::GetDataSize ( ) const
inline

Get the data size in bytes that is expected to be used. Some media streams can make use of this information to perform optimisations.

References defaultDataSize.

PString OpalMediaStream::GetID ( ) const
inline

Get the ID associated with this stream. Used for detecting two the streams associated with a bidirectional media channel

References identifier.

bool OpalMediaStream::GetMarker ( ) const
inline

Get the marker bit of last read.

References marker.

virtual OpalMediaFormat OpalMediaStream::GetMediaFormat ( ) const
virtual

Get the currently selected media format. The media data format is a string representation of the format being transferred by the media channel. It is typically a value as provided by the RTP_PayloadType class.

The default behaviour simply returns the member variable "mediaFormat".

OpalMediaPatch* OpalMediaStream::GetPatch ( ) const
inline

Get the patch thread that is using the stream.

References mediaPatch.

unsigned OpalMediaStream::GetSessionID ( ) const
inline

Get the session number of the stream.

References sessionID.

virtual void OpalMediaStream::GetStatistics ( OpalMediaStatistics statistics,
bool  fromPatch = false 
) const
virtual

Reimplemented in OpalRTPMediaStream.

unsigned OpalMediaStream::GetTimestamp ( ) const
inline

Get the timestamp of last read.

References timestamp.

void OpalMediaStream::IncrementTimestamp ( PINDEX  size)
protected
virtual bool OpalMediaStream::InternalUpdateMediaFormat ( const OpalMediaFormat mediaFormat)
virtual
Parameters:
mediaFormatNew media format

Reimplemented in OpalVideoMediaStream.

bool OpalMediaStream::InternalWriteData ( const BYTE *  data,
PINDEX  length,
PINDEX &  written 
)
protected
bool OpalMediaStream::IsOpen ( ) const
inline

Returns true if the media stream is open.

References isOpen.

bool OpalMediaStream::IsPaused ( ) const
inline

Get the paused state for stream.

References m_paused.

bool OpalMediaStream::IsSink ( ) const
inline

Determine of media stream is a source or a sink.

References isSource.

bool OpalMediaStream::IsSource ( ) const
inline

Determine of media stream is a source or a sink.

References isSource.

virtual PBoolean OpalMediaStream::IsSynchronous ( ) const
pure virtual

Indicate if the media stream is synchronous. If this returns true then the media stream will block of the amount of time it takes to annunciate the data. For example if the media stream is over a sound card, and 480 bytes of data are to be written it will take 30 milliseconds to complete.

Implemented in OpalUDPMediaStream, OpalVideoMediaStream, OpalMixerMediaStream, OpalFileMediaStream, OpalLineMediaStream, OpalRTPMediaStream, OpalNullMediaStream, OpalLocalMediaStream, OpalIMMediaStream, OpalIVRMediaStream, OpalH224MediaStream, and OpalIAX2MediaStream.

virtual void OpalMediaStream::OnStartMediaPatch ( )
virtual

Callback that is called on the source stream once the media patch has started. The default behaviour calls OpalConnection::OnMediaPatchStart()

Reimplemented in OpalH224MediaStream.

virtual void OpalMediaStream::OnStopMediaPatch ( OpalMediaPatch patch)
virtual

Callback that is called on the source stream once the media patch has started. The default behaviour calls OpalConnection::OnMediaPatchStop()

Parameters:
patchMedia patch that is stopping
virtual PBoolean OpalMediaStream::Open ( )
virtual

Open the media stream using the media format.

   The default behaviour simply sets the isOpen variable to true.

Reimplemented in OpalMixerMediaStream, OpalVideoMediaStream, OpalLineMediaStream, OpalRTPMediaStream, OpalMSRPMediaStream, OpalIVRMediaStream, and OpalIAX2MediaStream.

void OpalMediaStream::PrintOn ( ostream &  strm) const

Standard stream print function. The PObject class has a << operator defined that calls this function polymorphically.

Parameters:
strmStream to output text representation
bool OpalMediaStream::PushPacket ( RTP_DataFrame packet)

Pushes a frame to the patch

virtual PBoolean OpalMediaStream::ReadData ( BYTE *  data,
PINDEX  size,
PINDEX &  length 
)
virtual

Read raw media data from the source media stream. The default behaviour simply calls ReadPacket() on the data portion of the RTP_DataFrame and sets the frames timestamp and marker from the internal member variables of the media stream class.

Parameters:
dataData buffer to read to
sizeSize of buffer
lengthLength of data actually read

Reimplemented in OpalVideoMediaStream, OpalFileMediaStream, OpalRawMediaStream, OpalLineMediaStream, OpalNullMediaStream, and OpalLocalMediaStream.

virtual PBoolean OpalMediaStream::ReadPacket ( RTP_DataFrame packet)
virtual

Read an RTP frame of data from the source media stream. The default behaviour simply calls ReadData() on the data portion of the RTP_DataFrame and sets the frames timestamp and marker from the internal member variables of the media stream class.

Reimplemented in OpalUDPMediaStream, OpalLineMediaStream, OpalRTPMediaStream, OpalLocalMediaStream, OpalIMMediaStream, OpalMSRPMediaStream, OpalH224MediaStream, and OpalIAX2MediaStream.

bool OpalMediaStream::RemoveFilter ( const PNotifier &  filter,
const OpalMediaFormat stage = OpalMediaFormat() 
) const

Remove a filter from the owning patch safely.

Parameters:
filterFilter notifier to be called.
stageStage in codec pipeline to call filter
virtual PBoolean OpalMediaStream::RequiresPatchThread ( OpalMediaStream stream) const
virtual

Indicate if the media stream requires a OpalMediaPatch thread (active patch). This is called on the source/sink stream and is passed the sink/source stream that the patch will initially be using. The function could conditionally require the patch thread to execute a thread reading and writing data, or prevent it from doing so as it can do so in hardware in some way, e.g. both streams are on the same OpalLineInterfaceDevice.

The default behaviour simply returns true.

Parameters:
streamOther stream in patch

Reimplemented in OpalLineMediaStream.

virtual PBoolean OpalMediaStream::RequiresPatchThread ( ) const
virtual
virtual PBoolean OpalMediaStream::SetDataSize ( PINDEX  dataSize,
PINDEX  frameTime 
)
virtual

Set the data size in bytes that is expected to be used. Some media streams can make use of this information to perform optimisations.

The default behaviour does nothing.

Parameters:
dataSizeNew data size (in total)
frameTimeIndividual frame time (if applicable)

Reimplemented in OpalVideoMediaStream, OpalLineMediaStream, and OpalRTPMediaStream.

void OpalMediaStream::SetMarker ( bool  m)
inline

Set marker bit for next write.

References marker.

virtual PBoolean OpalMediaStream::SetPatch ( OpalMediaPatch patch)
virtual

Set the patch thread that is using this stream.

Parameters:
patchMedia patch thread

Reimplemented in OpalRTPMediaStream.

virtual bool OpalMediaStream::SetPaused ( bool  pause,
bool  fromPatch = false 
)
virtual

Set the paused state for stream. This will stop reading/writing data from the stream. Returns true if the pause state was changed

Parameters:
pauseIndicate that the stream should be paused
fromPatchIs being called from OpalMediaPatch

Reimplemented in OpalRTPMediaStream.

void OpalMediaStream::SetSessionID ( unsigned  id)
inline

Get the session number of the stream.

void OpalMediaStream::SetTimestamp ( unsigned  ts)
inline

Set timestamp for next write.

References timestamp.

virtual PBoolean OpalMediaStream::Start ( )
virtual

Start the media stream.

   The default behaviour calls Resume() on the associated OpalMediaPatch
   thread if it was suspended.

Reimplemented in OpalIAX2MediaStream.

bool OpalMediaStream::UpdateMediaFormat ( const OpalMediaFormat mediaFormat)

Update the media format. This can be used to adjust the parameters of a codec at run time. Note you cannot change the basic media format, eg change GSM0610 to G.711, only options for that format, eg 6k3 mode to 5k3 mode in G.723.1. If the formats are different then a OpalMediaFormat::Merge() is performed.

The default behaviour updates the mediaFormat member variable and pases the value on to the OpalMediaPatch.

Parameters:
mediaFormatNew media format
virtual PBoolean OpalMediaStream::WriteData ( const BYTE *  data,
PINDEX  length,
PINDEX &  written 
)
virtual

Write raw media data to the sink media stream. The default behaviour calls WritePacket() on the data portion of the RTP_DataFrame and and sets the internal timestamp and marker from the member variables of the media stream class.

Parameters:
dataData to write
lengthLength of data to read.
writtenLength of data actually written

Reimplemented in OpalVideoMediaStream, OpalFileMediaStream, OpalRawMediaStream, OpalLineMediaStream, OpalNullMediaStream, OpalLocalMediaStream, and OpalIAX2MediaStream.

virtual PBoolean OpalMediaStream::WritePacket ( RTP_DataFrame packet)
virtual

Write an RTP frame of data to the sink media stream. The default behaviour simply calls WriteData() on the data portion of the RTP_DataFrame and and sets the internal timestamp and marker from the member variables of the media stream class.

Reimplemented in OpalUDPMediaStream, OpalMixerMediaStream, OpalLineMediaStream, OpalRTPMediaStream, OpalLocalMediaStream, OpalIMMediaStream, OpalMSRPMediaStream, and OpalH224MediaStream.

virtual PBoolean OpalMediaStream::WritePackets ( RTP_DataFrameList &  packets)
virtual

Write a list of RTP frames of data to the sink media stream. The default behaviour simply calls WritePacket() on each of the elements in the list.


Field Documentation

OpalConnection& OpalMediaStream::connection
protected

Reimplemented in OpalIAX2MediaStream.

Referenced by GetConnection().

PINDEX OpalMediaStream::defaultDataSize
protected

Referenced by GetDataSize().

PString OpalMediaStream::identifier
protected

Referenced by GetID().

bool OpalMediaStream::isOpen
protected

Referenced by IsOpen().

bool OpalMediaStream::isSource
protected
PINDEX OpalMediaStream::m_frameSize
protected
unsigned OpalMediaStream::m_frameTime
protected
bool OpalMediaStream::m_paused
protected

Referenced by IsPaused().

RTP_DataFrame::PayloadTypes OpalMediaStream::m_payloadType
protected
bool OpalMediaStream::marker
protected

Referenced by GetMarker(), and SetMarker().

OpalMediaFormat OpalMediaStream::mediaFormat
protected
OpalMediaPatch* OpalMediaStream::mediaPatch
protected

Referenced by GetPatch().

unsigned OpalMediaStream::mismatchedPayloadTypes
protected
unsigned OpalMediaStream::sessionID
protected

Referenced by GetSessionID().

unsigned OpalMediaStream::timestamp
protected

Referenced by GetTimestamp(), and SetTimestamp().


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