OpalMediaStream Class Reference

#include <mediastrm.h>

Inheritance diagram for OpalMediaStream:
OpalFaxMediaStream OpalH224MediaStream OpalLineMediaStream OpalLocalMediaStream OpalNullMediaStream OpalRawMediaStream OpalRTPMediaStream OpalUDPMediaStream

List of all members.

Public Member Functions

Overrides from PObject

void PrintOn (ostream &strm) const
Operations

virtual OpalMediaFormat GetMediaFormat () const
virtual bool UpdateMediaFormat (const OpalMediaFormat &mediaFormat, bool fromPatch=false)
virtual PBoolean ExecuteCommand (const OpalMediaCommand &command)
virtual void SetCommandNotifier (const PNotifier &notifier)
virtual PBoolean Open ()
virtual PBoolean Start ()
virtual PBoolean Close ()
virtual void OnPatchStart ()
virtual void OnPatchStop ()
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 *sinkStream) const
virtual PBoolean RequiresPatchThread () const
virtual void EnableJitterBuffer () const
Member variable access

OpalConnectionGetConnection () const
bool IsSource () const
bool IsSink () const
unsigned GetSessionID () const
PString GetID () const
unsigned GetTimestamp () const
void SetTimestamp (unsigned ts)
bool GetMarker () const
void SetMarker (bool m)
bool IsPaused () const
virtual void SetPaused (bool pause)
bool IsOpen () const
virtual PBoolean SetPatch (OpalMediaPatch *patch)
virtual void RemovePatch (OpalMediaPatch *patch)
OpalMediaPatchGetPatch () const
void AddFilter (const PNotifier &Filter, const OpalMediaFormat &Stage=OpalMediaFormat())
bool RemoveFilter (const PNotifier &Filter, const OpalMediaFormat &Stage)
virtual void GetStatistics (OpalMediaStatistics &statistics, bool fromPatch=false) const

Protected Attributes

OpalConnectionconnection
unsigned sessionID
PString identifier
OpalMediaFormat mediaFormat
bool paused
bool isSource
bool isOpen
PINDEX defaultDataSize
unsigned timestamp
bool marker
unsigned mismatchedPayloadTypes
OpalMediaPatchmediaPatch
PNotifier commandNotifier

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:
mediaFormat Media format for stream
sessionID Session number for stream
isSource Is 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() 
)

Add a filter to the owning patch safely.

virtual PBoolean OpalMediaStream::Close (  )  [virtual]

Close the media stream.

The default does nothing.

Reimplemented in OpalH224MediaStream, OpalLineMediaStream, OpalRTPMediaStream, OpalRawMediaStream, OpalUDPMediaStream, and OpalFaxMediaStream.

virtual void OpalMediaStream::EnableJitterBuffer (  )  const [virtual]

Enable jitter buffer for the media stream.

The default behaviour does nothing.

Reimplemented in OpalRTPMediaStream.

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

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

The default behaviour passes the command on to the OpalMediaPatch.

Parameters:
command Command 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.

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

Reimplemented in OpalRTPMediaStream, and OpalFaxMediaStream.

unsigned OpalMediaStream::GetTimestamp (  )  const [inline]

Get the timestamp of last read.

References timestamp.

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 paused.

bool OpalMediaStream::IsSink (  )  const [inline]

Determine of media stream is a source or a sink.

bool OpalMediaStream::IsSource (  )  const [inline]

Determine of media stream is a source or a sink.

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 OpalH224MediaStream, OpalLineMediaStream, OpalLocalMediaStream, OpalNullMediaStream, OpalRTPMediaStream, OpalFileMediaStream, OpalAudioMediaStream, OpalUDPMediaStream, and OpalFaxMediaStream.

virtual void OpalMediaStream::OnPatchStart (  )  [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::OnPatchStop (  )  [virtual]

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

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 OpalLineMediaStream, OpalRTPMediaStream, and OpalFaxMediaStream.

void OpalMediaStream::PrintOn ( ostream &  strm  )  const

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

Parameters:
strm Stream 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:
data Data buffer to read to
size Size of buffer
length Length of data actually read

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

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 OpalH224MediaStream, OpalLineMediaStream, OpalLocalMediaStream, OpalRTPMediaStream, OpalUDPMediaStream, OpalFaxMediaStream, and OpalT38MediaStream.

bool OpalMediaStream::RemoveFilter ( const PNotifier &  Filter,
const OpalMediaFormat Stage 
)

Remove a filter from the owning patch safely.

virtual void OpalMediaStream::RemovePatch ( OpalMediaPatch patch  )  [virtual]

Remove the patch thread that is using this stream. This function is useful in case of streams which can be accessed by multiple instances of OpalMediaPatch.

The default behaviour simply sets patchThread to NULL.

virtual PBoolean OpalMediaStream::RequiresPatchThread (  )  const [virtual]

Reimplemented in OpalH224MediaStream, and OpalNullMediaStream.

virtual PBoolean OpalMediaStream::RequiresPatchThread ( OpalMediaStream sinkStream  )  const [virtual]

Indicate if the media stream requires a OpalMediaPatch thread (active patch). This is called on the source stream and is passed the sink 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. if both streams where on the same OpalLineInterfaceDevice.

The default behaviour simply returns true.

Parameters:
sinkStream Sink stream for this source

Reimplemented in OpalLineMediaStream.

virtual void OpalMediaStream::SetCommandNotifier ( const PNotifier &  notifier  )  [virtual]

Set a notifier to receive commands generated by the transcoder. The commands are highly context sensitive, for example VideoFastUpdate would only apply to a video transcoder.

The default behaviour passes the command on to the OpalMediaPatch and sets the member variable commandNotifier.

Parameters:
notifier Command to execute.
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:
dataSize New data size (in total)
frameTime Individual frame time (if applicable)

Reimplemented in OpalLineMediaStream, OpalRTPMediaStream, and OpalAudioMediaStream.

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:
patch Media patch thread
virtual void OpalMediaStream::SetPaused ( bool  pause  )  [virtual]

Set the paused state for stream. This will stop reading/writing data from the stream.

Parameters:
pause Indicate that the stream should be paused
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.

virtual bool OpalMediaStream::UpdateMediaFormat ( const OpalMediaFormat mediaFormat,
bool  fromPatch = false 
) [virtual]

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:
mediaFormat New media format
fromPatch Is being called from OpalMediaPatch
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:
data Data to write
length Length of data to read.
written Length of data actually written

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

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 OpalH224MediaStream, OpalLineMediaStream, OpalLocalMediaStream, OpalRTPMediaStream, OpalUDPMediaStream, OpalFaxMediaStream, and OpalT38MediaStream.

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.


Member Data Documentation

PNotifier OpalMediaStream::commandNotifier [protected]

Referenced by GetConnection().

Referenced by GetDataSize().

PString OpalMediaStream::identifier [protected]

Referenced by GetID().

bool OpalMediaStream::isOpen [protected]

Referenced by IsOpen().

bool OpalMediaStream::isSource [protected]
bool OpalMediaStream::marker [protected]

Referenced by GetMarker(), and SetMarker().

Referenced by GetPatch().

bool OpalMediaStream::paused [protected]

Referenced by IsPaused().

unsigned OpalMediaStream::sessionID [protected]
unsigned OpalMediaStream::timestamp [protected]

Referenced by GetTimestamp(), and SetTimestamp().


The documentation for this class was generated from the following file:
Generated on Tue Jun 15 00:29:16 2010 for OPAL by  doxygen 1.6.3