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Protected Member Functions | Protected Attributes
OpalMediaStream Class Reference

`#include <mediastrm.h>`

Inheritance diagram for OpalMediaStream:

## 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
OpalConnection & | GetConnection () 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)
OpalMediaPatch * | GetPatch () 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

OpalConnection & | connection
unsigned | sessionID
PString | identifier
OpalMediaFormat | mediaFormat
bool | m_paused
bool | isSource
bool | isOpen
PINDEX | defaultDataSize
unsigned | timestamp
bool | marker
unsigned | mismatchedPayloadTypes
OpalMediaPatch * | mediaPatch
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:

  conn | Connection that owns the stream
  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()`
| ) |  | const

Add a filter to the owning patch safely.

Parameters:

  filter | Filter notifier to be called.
  stage | Stage in codec pipeline to call filter

virtual PBoolean OpalMediaStream::Close | ( |  | ) |

virtual

Close the media stream.

       The default does nothing.

Reimplemented in OpalUDPMediaStream, OpalMixerMediaStream, OpalVideoMediaStream, OpalRawMediaStream, OpalLineMediaStream, OpalRTPMediaStream, OpalMSRPMediaStream, OpalIVRMediaStream, OpalH224MediaStream, and OpalIAX2MediaStream.

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:

  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.

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:

  mediaFormat | New 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:

  patch | Media 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:

  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 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:

  filter | Filter notifier to be called.
  stage | Stage 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:

  stream | Other stream in patch

Reimplemented in OpalLineMediaStream.

virtual PBoolean OpalMediaStream::RequiresPatchThread | ( |  | ) | const

virtual

Reimplemented in OpalMixerMediaStream, OpalRTPMediaStream, OpalNullMediaStream, OpalIMMediaStream, OpalMSRPMediaStream, and OpalH224MediaStream.

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 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:

  patch | Media 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:

  pause | Indicate that the stream should be paused
  fromPatch | Is 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:

  mediaFormat | New 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:

  data | Data to write
  length | Length of data to read.
  written | Length 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

Referenced by IsSink(), IsSource(), and OpalMSRPMediaStream::RequiresPatchThread().

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:

- mediastrm.h