OpalAudioMixer Class Reference

#include <opalmixer.h>

Inheritance 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, unsigned minJitterDelay, unsigned maxJitterDelay)
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 Attributes
bool	m_stereo
unsigned	m_sampleRate
AudioStream *	m_left
AudioStream *	m_right
std::vector< int >	m_mixedAudio

---

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

(

)

[protected, virtual]

Implements OpalBaseMixer.

virtual size_t OpalAudioMixer::GetOutputSize

(

)

const [protected, virtual]

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

)

[protected, virtual]

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,
		unsigned	minJitterDelay,
		unsigned	maxJitterDelay
	)

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
	minJitterDelay	Minimum jitter buffer delay in RTP timestamp units
	maxJitterDelay	Maximum jitter buffer delay in RTP timestamp units

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

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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