OpalMediaPatch Class Reference

`#include <patch.h>`

Inheritance diagram for OpalMediaPatch:

## Data Structures

class | Filter
class | Sink
class | Thread

## Public Member Functions

| PDECLARE_NOTIFIER (OpalMediaCommand, OpalMediaPatch, OnMediaCommand)
Construction
| OpalMediaPatch (OpalMediaStream &source)
| ~OpalMediaPatch ()
Overrides from PObject
void | PrintOn (ostream &strm) const
Operations
virtual void | Start ()
virtual bool | OnStartMediaPatch ()
virtual void | Close ()
PBoolean | AddSink (const OpalMediaStreamPtr &stream)
void | RemoveSink (const OpalMediaStreamPtr &stream)
OpalMediaStream & | GetSource () const
OpalMediaStreamPtr | GetSink (PINDEX i=0) const
OpalMediaFormat | GetSinkFormat (PINDEX i=0) const
void | AddFilter (const PNotifier &filter, const OpalMediaFormat &stage=OpalMediaFormat())
bool | RemoveFilter (const PNotifier &filter, const OpalMediaFormat &stage=OpalMediaFormat())
virtual void | FilterFrame (RTP_DataFrame &frame, const OpalMediaFormat &mediaFormat)
virtual bool | UpdateMediaFormat (const OpalMediaFormat &mediaFormat)
virtual PBoolean | ExecuteCommand (const OpalMediaCommand &command, PBoolean fromSink)
virtual bool | SetPaused (bool pause)
virtual PBoolean | PushFrame (RTP_DataFrame &frame)
bool | SetBypassPatch (OpalMediaPatch *patch)
virtual OpalTranscoder * | GetAndLockSinkTranscoder (PINDEX i=0) const
virtual void | UnLockSinkTranscoder () const
virtual void | GetStatistics (OpalMediaStatistics &statistics, bool fromSink) const

## Protected Member Functions

virtual void | Main ()
void | StopThread ()
bool | DispatchFrame (RTP_DataFrame &frame)
bool | EnableJitterBuffer ()

## Protected Attributes

OpalMediaStream & | source
PList< Sink > | sinks
PList< Filter > | filters
OpalMediaPatch * | m_bypassToPatch
OpalMediaPatch * | m_bypassFromPatch
PSyncPoint | m_bypassEnded
Thread * | patchThread
PMutex | patchThreadMutex

## Detailed Description

Media stream "patch cord". This class is the thread of control that transfers data from one "source" OpalMediStream to one or more other "sink" OpalMediStream instances. It may use zero, one or two intermediary software codecs for each sink stream in order to match the media data formats the streams are capabile of doing natively.

Note the thread is not actually started straight away. It is expected that the Start() function is called on the patch when the creator code is ready for it to begin. For example all sink streams have been added.

## Constructor & Destructor Documentation

OpalMediaPatch::OpalMediaPatch | ( | OpalMediaStream & | source | ) |

Create a new patch. Note the thread is not started here.

Parameters

  source | Source media stream

OpalMediaPatch::~OpalMediaPatch | ( |  | ) |

Destroy patch.

## Member Function Documentation

void OpalMediaPatch::AddFilter | ( | const PNotifier & | filter,
|  | const OpalMediaFormat & | stage = `OpalMediaFormat()`
| ) |  |

Add a filter to the media pipeline. Use PDECLARE_NOTIFIER(RTP_DataFrame, YourClass, YourFunction) for the filter function notifier.

Parameters

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

PBoolean OpalMediaPatch::AddSink | ( | const OpalMediaStreamPtr & | stream | ) |

Add another "sink" OpalMediaStream to patch. The stream must not be a ReadOnly media stream for the patch to be able to write to it.

Parameters

  stream | Media stream to add.

virtual void OpalMediaPatch::Close | ( |  | ) |

virtual

Close the patch. This is an internal function that closes all of the sink streams and waits for the the thread to terminate. It is called when the source stream is called.

bool OpalMediaPatch::DispatchFrame | ( | RTP_DataFrame & | frame | ) |

protected

bool OpalMediaPatch::EnableJitterBuffer | ( |  | ) |

protected

virtual PBoolean OpalMediaPatch::ExecuteCommand | ( | const OpalMediaCommand & | command,
|  | PBoolean | fromSink
| ) |  |

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 source or sinks and the sinks transcoders.

Returns
  true if command is handled.

Parameters

  command | Command to execute.
  fromSink | Flag for source or sink

virtual void OpalMediaPatch::FilterFrame | ( | RTP_DataFrame & | frame,
|  | const OpalMediaFormat & | mediaFormat
| ) |  |

virtual

Filter a frame. Calls all filter functions.

virtual OpalTranscoder* OpalMediaPatch::GetAndLockSinkTranscoder | ( | PINDEX | i = `0` | ) | const

virtual

Get the transcoder used within a sink stream

OpalMediaStreamPtr OpalMediaPatch::GetSink | ( | PINDEX | i = `0` | ) | const

Get the media stream for a sink stream

OpalMediaFormat OpalMediaPatch::GetSinkFormat | ( | PINDEX | i = `0` | ) | const

Get the media format for a sink stream

OpalMediaStream& OpalMediaPatch::GetSource | ( |  | ) | const

inline

Get the current source stream for patch.

References source.

virtual void OpalMediaPatch::GetStatistics | ( | OpalMediaStatistics & | statistics,
|  | bool | fromSink
| ) |  | const

virtual

virtual void OpalMediaPatch::Main | ( |  | ) |

protected virtual

Called from the associated patch thread

virtual bool OpalMediaPatch::OnStartMediaPatch | ( |  | ) |

virtual

Indicate the patch has started. Typically called from the beginning of the patch thread.

Default behaviour make sure jitter buffer is created.

Returns bool indicating all media streams are asynchronous so the patch should assure no thread startvation

OpalMediaPatch::PDECLARE_NOTIFIER | ( | OpalMediaCommand | ,
|  | OpalMediaPatch | ,
|  | OnMediaCommand |
| ) |  |

void OpalMediaPatch::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

virtual PBoolean OpalMediaPatch::PushFrame | ( | RTP_DataFrame & | frame | ) |

virtual

Push a frame out to all the sink streams, transcoding as necessary.

Parameters

  frame | Frame to push

bool OpalMediaPatch::RemoveFilter | ( | const PNotifier & | filter,
|  | const OpalMediaFormat & | stage = `OpalMediaFormat()`
| ) |  |

Remove a filter from the media pipeline.

Parameters

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

void OpalMediaPatch::RemoveSink | ( | const OpalMediaStreamPtr & | stream | ) |

Add existing "sink" OpalMediaStream to patch. If the stream is not a sink of this patch then this function does nothing.

Parameters

  stream | Media stream to remove

bool OpalMediaPatch::SetBypassPatch | ( | OpalMediaPatch * | patch | ) |

Set bypass patch instance.

This can be useful for back to back calls that happen to be the same media format and you wish to avoid double decoding and encoding of media. Note this scenario is not the same as two OpalConnections within the same OpalCall, but two completely independent OpalCall where one connection is to be bypassed. For example, two OpalCall instances might have two SIPConnection instances and two OpalMixerConnection instances connected via a single OpalMixerNode. Now while there are ONLY two calls in the node, it is a waste to decode the audio, add to mixer and re-encode it again. In practice this is identical to just bypassing the mixer node completely, until a third party is added, then we need to switch back to normal (non-bypassed) operation.

Note it is up to the caller to assure the patch instance lifetimes are correct for the bypass.

Returns
  true if bypass was set, false if conflict with another bypass.

virtual bool OpalMediaPatch::SetPaused | ( | bool | pause | ) |

virtual

Set streams to paused.

Parameters

  pause | Indicate that the stream should be paused

virtual void OpalMediaPatch::Start | ( |  | ) |

virtual

Start the patch. The default implementation simply starts the patch thread, which in turn calls Main()

Reimplemented in OpalPassiveMediaPatch.

void OpalMediaPatch::StopThread | ( |  | ) |

protected

virtual void OpalMediaPatch::UnLockSinkTranscoder | ( |  | ) | const

virtual

virtual bool OpalMediaPatch::UpdateMediaFormat | ( | const OpalMediaFormat & | mediaFormat | ) |

virtual

Update the source/sink 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 source/sink media stream and the output side of any relevant transcoders.

Parameters

  mediaFormat | New media format

## Field Documentation

PList<Filter> OpalMediaPatch::filters

protected

PSyncPoint OpalMediaPatch::m_bypassEnded

protected

OpalMediaPatch* OpalMediaPatch::m_bypassFromPatch

protected

OpalMediaPatch* OpalMediaPatch::m_bypassToPatch

protected

Thread* OpalMediaPatch::patchThread

protected

PMutex OpalMediaPatch::patchThreadMutex

protected

PList<Sink> OpalMediaPatch::sinks

protected

OpalMediaStream& OpalMediaPatch::source

protected

Referenced by GetSource().

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

- patch.h