OpalBaseMixer Class Reference

#include <opalmixer.h>

Inheritance 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)
void	StartPushThread ()
void	StopPushThread (bool lock=true)
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
virtual bool	OnPush ()
void	PushThreadMain ()
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
PMutex	m_mutex

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 ( ) [protected, pure virtual]

Implemented in OpalAudioMixer, and OpalVideoMixer.

virtual size_t OpalBaseMixer::GetOutputSize ( ) const [protected, pure virtual]

Implemented in OpalAudioMixer, and OpalVideoMixer.

unsigned OpalBaseMixer::GetPeriodTS ( ) const [inline]

Get the period for mixing in RTP timestamp units.

References m_periodTS.

virtual bool OpalBaseMixer::MixStreams ( RTP_DataFrame & frame ) [protected, pure virtual]

Implemented in OpalAudioMixer, and OpalVideoMixer.

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,Poitner

to mixed media.

Reimplemented in OpalMixerNode::VideoMixer.

virtual bool OpalBaseMixer::OnPush ( ) [protected, virtual]

Reimplemented in OpalMixerNode::AudioMixer.

void OpalBaseMixer::PushThreadMain ( ) [protected]

virtual bool OpalBaseMixer::ReadMixed ( RTP_DataFrame & mixed ) [virtual]

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 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.

void OpalBaseMixer::StartPushThread ( )

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: