OpalAudioMixer Class Reference

#include <opalmixer.h>

Inheritance diagram for OpalAudioMixer:

Collaboration diagram for OpalAudioMixer:

Data Structures
struct	AudioStream

Public Member Functions
	OpalAudioMixer (bool stereo=false, unsigned sampleRate=OpalMediaFormat::AudioClockRate, bool pushThread=true, unsigned period=10)
	~OpalAudioMixer ()
virtual void	RemoveStream (const Key_T &key)
virtual void	RemoveAllStreams ()
bool	IsStereo () const
unsigned	GetSampleRate () const
bool	SetSampleRate (unsigned rate)
bool	SetJitterBufferSize (const Key_T &key, const OpalJitterBuffer::Init &init)
Public Member Functions inherited from OpalBaseMixer
	OpalBaseMixer (bool pushThread, unsigned periodMS, unsigned periodTS)
virtual	~OpalBaseMixer ()
virtual bool	AddStream (const Key_T &key)
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 Member Functions
virtual Stream *	CreateStream ()
virtual bool	MixStreams (RTP_DataFrame &frame)
virtual size_t	GetOutputSize () const
void	PreMixStreams ()
void	MixStereo (RTP_DataFrame &frame)
void	MixAdditive (RTP_DataFrame &frame, const short *audioToSubtract)
Protected Member Functions inherited from OpalBaseMixer
virtual bool	OnPush ()
void	PushThreadMain ()

Protected Attributes
bool	m_stereo
unsigned	m_sampleRate
AudioStream *	m_left
AudioStream *	m_right
std::vector< int >	m_mixedAudio
Protected Attributes inherited from OpalBaseMixer
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

Additional Inherited Members
Public Types inherited from OpalBaseMixer
typedef PString	Key_T
Protected Types inherited from OpalBaseMixer
typedef std::map< Key_T, Stream * >	StreamMap_T

Detailed Description

Class for an audio mixer. This takes raw PCM-16 data and sums all the input data streams to produce a single PCM-16 sample value.

For 2 or less channels, they may be mixed as stereo where 16 bit PCM samples are placed in adjacent pairs in the output, rather than summing them.

Constructor & Destructor Documentation

OpalAudioMixer::OpalAudioMixer	(	bool	stereo = false,
		unsigned	sampleRate = OpalMediaFormat::AudioClockRate,
		bool	pushThread = true,
		unsigned	period = 10
	)

Parameters

stereo	Indicate stero or mixed mono mode
sampleRate	Sample rate for audio, default 8kHz
pushThread	Indicate push thread is to be used
period	Period for push/pull of audio from mixer in milliseconds

OpalAudioMixer::~OpalAudioMixer ( )

inline

References OpalBaseMixer::StopPushThread().

Member Function Documentation

virtual Stream* OpalAudioMixer::CreateStream ( )

protectedvirtual

Implements OpalBaseMixer.

virtual size_t OpalAudioMixer::GetOutputSize ( ) const

protectedvirtual

Implements OpalBaseMixer.

unsigned OpalAudioMixer::GetSampleRate ( ) const

inline

Get sample rate for audio.

References m_sampleRate.

bool OpalAudioMixer::IsStereo ( ) const

inline

Return flag for mixing stereo audio data.

References m_stereo.

void OpalAudioMixer::MixAdditive ( RTP_DataFrame &  frame, const short *  audioToSubtract  )

protected

void OpalAudioMixer::MixStereo ( RTP_DataFrame &  frame )

protected

virtual bool OpalAudioMixer::MixStreams ( RTP_DataFrame &  frame )

protectedvirtual

Implements OpalBaseMixer.

void OpalAudioMixer::PreMixStreams ( )

protected

virtual void OpalAudioMixer::RemoveAllStreams ( )

virtual

Remove all input streams from mixer.

Reimplemented from OpalBaseMixer.

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

virtual

Remove an input stream from mixer.

Parameters

key	key for mixer stream

Reimplemented from OpalBaseMixer.

bool OpalAudioMixer::SetJitterBufferSize	(	const Key_T &	key,
		const OpalJitterBuffer::Init &	init
	)

Sets the size of the jitter buffer to be used by the specified stream in this mixer. A mixer defaults to not having any jitter buffer enabled.

If either jitter delay parameter is zero, it destroys the jitter buffer attached to this mixer.

Parameters

key	key for mixer stream
init	Initialisation information

bool OpalAudioMixer::SetSampleRate

(

unsigned

rate

)

Set sample rate for audio data. Note that all streams must have the same sample rate.

Returns false if attempts to set sample rate to something different to existing streams.

Parameters

rate

New rate

Field Documentation

AudioStream* OpalAudioMixer::m_left

protected

std::vector<int> OpalAudioMixer::m_mixedAudio

protected

AudioStream* OpalAudioMixer::m_right

protected

unsigned OpalAudioMixer::m_sampleRate

protected

Referenced by GetSampleRate().

bool OpalAudioMixer::m_stereo

protected

Referenced by IsStereo().

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

• opalmixer.h