OpalBaseMixer Class Reference

#include <opalmixer.h>

Inheritance diagram for OpalBaseMixer:

Collaboration diagram for OpalBaseMixer:

Data Structures
struct	Stream

Public Types
typedef PString	Key_T

Public Member Functions
	OpalBaseMixer (bool pushThread, unsigned periodMS, unsigned periodTS)
virtual	~OpalBaseMixer ()
virtual bool	AddStream (const Key_T &key)
virtual void	RemoveStream (const Key_T &key)
virtual void	RemoveAllStreams ()
virtual bool	WriteStream (const Key_T &key, const RTP_DataFrame &input)
virtual RTP_DataFrame *	ReadMixed ()
virtual bool	ReadMixed (RTP_DataFrame &mixed)
virtual bool	OnMixed (RTP_DataFrame *&mixed)
virtual void	StartPushThread ()
virtual bool	OnPush ()
void	StopPushThread (bool lock=true)
unsigned	GetPeriodMS () const
unsigned	GetPeriodTS () const

Protected Types
typedef std::map< Key_T, Stream * >	StreamMap_T

Protected Member Functions
virtual Stream *	CreateStream ()=0
virtual bool	MixStreams (RTP_DataFrame &frame)=0
virtual size_t	GetOutputSize () const =0
void	PushThreadMain ()
	PDECLARE_MUTEX (m_mutex)

Protected Attributes
bool	m_pushThread
unsigned	m_periodMS
unsigned	m_periodTS
StreamMap_T	m_inputStreams
unsigned	m_outputTimestamp
RTP_DataFrame *	m_pushFrame
PThread *	m_workerThread
bool	m_threadRunning

Detailed Description

Class base for a media mixer.

The mixer operates by re-buffering the input media into chunks each with an associated timestamp. A main mixer thread then reads from each stream at regular intervals, mixes the media and creates the output buffer.

Note the timestamps of the input media are extremely important as they are used so that breaks or too fast data in the input media is dealt with correctly.

Member Typedef Documentation

typedef PString OpalBaseMixer::Key_T

typedef std::map<Key_T, Stream *> OpalBaseMixer::StreamMap_T

protected

Constructor & Destructor Documentation

OpalBaseMixer::OpalBaseMixer	(	bool	pushThread,
		unsigned	periodMS,
		unsigned	periodTS
	)

Parameters

pushThread	Indicate if the push thread should be started
periodMS	The output buffer time in milliseconds
periodTS	The output buffer time in RTP timestamp units

virtual OpalBaseMixer::~OpalBaseMixer ( )

virtual

Member Function Documentation

virtual bool OpalBaseMixer::AddStream ( const Key_T &  key )

virtual

Add a stream to mixer using the specified key.

Parameters

key	key for mixer stream

virtual Stream* OpalBaseMixer::CreateStream ( )

protectedpure virtual

Implemented in OpalVideoMixer, and OpalAudioMixer.

virtual size_t OpalBaseMixer::GetOutputSize ( ) const

protectedpure virtual

Implemented in OpalVideoMixer, and OpalAudioMixer.

unsigned OpalBaseMixer::GetPeriodMS ( ) const

inline

Get the period for mixing in milliseconds.

References m_periodMS.

unsigned OpalBaseMixer::GetPeriodTS ( ) const

inline

Get the period for mixing in RTP timestamp units.

References m_periodTS.

virtual bool OpalBaseMixer::MixStreams ( RTP_DataFrame &  frame )

protectedpure virtual

Implemented in OpalVideoMixer, and OpalAudioMixer.

virtual bool OpalBaseMixer::OnMixed ( RTP_DataFrame *&  mixed )

virtual

Mixed data is now available. For a push model system, this is called with mixed data as returned by ReadMixed().

The "mixed" parameter is a reference to a pointer, so if the consumer wishes to take responsibility for deleting the pointer to an RTP data frame, then they can set it to NULL.

If false is returned then the push thread is exited.

Parameters

mixed

Pointer to mixed media.

Reimplemented in OpalVideoStreamMixer.

virtual bool OpalBaseMixer::OnPush ( )

virtual

Push collected input through the mixer to output. This would normally be called from a thread, on a metronomic basis, from a thread started via StartPushThread(), however if m_pushThread is false, that thread is suppressed and it is expected the application would call this function as required.

Reimplemented in OpalAudioStreamMixer.

OpalBaseMixer::PDECLARE_MUTEX ( m_mutex  )

protected

void OpalBaseMixer::PushThreadMain ( )

protected

virtual RTP_DataFrame* OpalBaseMixer::ReadMixed ( )

virtual

Read media from mixer. A pull model system would call this function to get the mixed media from the mixer. Note the stream indicated by the streamToIgnore key is not included in the mixing operation, allowing for example, the member of a conference to not hear themselves.

Note this function is the function that does all the "heavy lifting" for the mixer.

virtual bool OpalBaseMixer::ReadMixed ( RTP_DataFrame &  mixed )

virtual

virtual void OpalBaseMixer::RemoveAllStreams ( )

virtual

Remove all input streams from mixer.

Reimplemented in OpalAudioMixer.

virtual void OpalBaseMixer::RemoveStream ( const Key_T &  key )

virtual

Remove an input stream from mixer.

Parameters

key	key for mixer stream

Reimplemented in OpalAudioMixer.

virtual void OpalBaseMixer::StartPushThread ( )

virtual

Start the push thread. Normally called internally.

void OpalBaseMixer::StopPushThread

(

bool

lock = true

)

Stop the push thread. This will wait for th epush thread to terminate, so care must be taken to avoid deadlocks when calling.

Referenced by OpalAudioMixer::~OpalAudioMixer(), and OpalVideoMixer::~OpalVideoMixer().

virtual bool OpalBaseMixer::WriteStream ( const Key_T &  key, const RTP_DataFrame &  input  )

virtual

Write an RTP data frame to mixer. A copy of the RTP data frame is created. This function is generally quite fast as the actual mixing is done in a different thread so minimal interference with the normal media stream processing occurs.

Parameters

key	key for mixer stream
input	Input RTP data for media

Field Documentation

StreamMap_T OpalBaseMixer::m_inputStreams

protected

unsigned OpalBaseMixer::m_outputTimestamp

protected

unsigned OpalBaseMixer::m_periodMS

protected

Referenced by OpalVideoMixer::GetFrameRate(), and GetPeriodMS().

unsigned OpalBaseMixer::m_periodTS

protected

Referenced by GetPeriodTS().

RTP_DataFrame* OpalBaseMixer::m_pushFrame

protected

bool OpalBaseMixer::m_pushThread

protected

bool OpalBaseMixer::m_threadRunning

protected

PThread* OpalBaseMixer::m_workerThread

protected

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

• opalmixer.h