AudioDataLib::SampleBasedSynth Class Reference

This class knows how to synthesize real-time sound as a function of MIDI messages and WaveTableData. More...

#include <SampleBasedSynth.h>

Inheritance diagram for AudioDataLib::SampleBasedSynth:

Public Member Functions
	SampleBasedSynth ()
virtual	~SampleBasedSynth ()
virtual bool	ReceiveMessage (double deltaTimeSeconds, const uint8_t *message, uint64_t messageSize, Error &error) override
virtual SynthModule *	GetRootModule (uint16_t channel) override
virtual bool	Process (Error &error) override
virtual bool	Initialize (Error &error) override
bool	SetChannelInstrument (uint8_t channel, uint8_t instrument, Error &error)
bool	GetChannelInstrument (uint8_t channel, uint8_t &instrument) const
void	SetWaveTableData (std::shared_ptr< WaveTableData > &waveTableData)
std::shared_ptr< WaveTableData >	GetWaveTableData ()
void	Clear ()
void	SetReverbEnabled (bool reverbEnabled)
bool	GetReverbEnabled ()
Public Member Functions inherited from AudioDataLib::MidiSynth
	MidiSynth ()
virtual	~MidiSynth ()
void	SetAudioStream (std::shared_ptr< AudioStream > audioStream)
std::shared_ptr< AudioStream >	GetAudioStream ()
void	SetMinMaxLatency (double minLatencySeconds, double maxLatencySeconds)
void	GetMinMaxLatency (double &minLatencySeconds, double &maxLatencySeconds) const
Public Member Functions inherited from AudioDataLib::MidiMsgDestination
	MidiMsgDestination ()
virtual	~MidiMsgDestination ()
virtual bool	Finalize (Error &error)

Additional Inherited Members
Static Public Member Functions inherited from AudioDataLib::MidiSynth
static double	MidiPitchToFrequency (uint8_t pitchValue)
static double	MidiVelocityToAmplitude (uint8_t velocityValue)
Protected Attributes inherited from AudioDataLib::MidiSynth
std::shared_ptr< AudioStream > *	audioStream
double	minLatencySeconds
	This is the minimum amount of audio (measured in seconds) that should always be buffered at any given time.
double	maxLatencySeconds
	This is the maximum amount of audio (measured in seconds) that should always be buffered at any given time.

Detailed Description

This class knows how to synthesize real-time sound as a function of MIDI messages and WaveTableData.

Constructor & Destructor Documentation

SampleBasedSynth()

SampleBasedSynth::SampleBasedSynth

(

)

~SampleBasedSynth()

SampleBasedSynth::~SampleBasedSynth ( )

virtual

Member Function Documentation

Clear()

void SampleBasedSynth::Clear

(

)

GetChannelInstrument()

bool SampleBasedSynth::GetChannelInstrument	(	uint8_t	channel,
		uint8_t &	instrument ) const

GetReverbEnabled()

bool AudioDataLib::SampleBasedSynth::GetReverbEnabled ( )

inline

GetRootModule()

SynthModule * SampleBasedSynth::GetRootModule ( uint16_t channel )

overridevirtual

A derived class must impliment this method to provide a SynthModule that can feed the given channel. Note that the term "channel" is overloaded. It can refer to a channel in a stream of audio (e.g., left, right, mono, etc.), as is the case here, or it can mean a MIDI channel, of which there are 16, so don't get them confused. Context usually makes it clear.

Implements AudioDataLib::MidiSynth.

GetWaveTableData()

std::shared_ptr< WaveTableData > AudioDataLib::SampleBasedSynth::GetWaveTableData ( )

inline

Initialize()

bool SampleBasedSynth::Initialize ( Error & error )

overridevirtual

This method will get called by the MidiMsgSource class during its own initialization.

Parameters

[out]

error

This should be populated with error information if false is returned.

Returns

True should be returned on success; false otherwise.

Reimplemented from AudioDataLib::MidiMsgDestination.

Process()

bool SampleBasedSynth::Process ( Error & error )

overridevirtual

This is where we strike a balance between keeping enough audio data buffered in our audio stream to prevent an audio drop-out while also not buffering too much so as to maintain the lowest possible latency. If we don't feed the audio buffer quick enough, we periodically have to feed silence to the audio stream. If we feed the audio buffer too much, then changes to the audio (such as a note turnning on or off) don't happen soon enough, or as close to when they actually happend as we would like. As far as drop-outs are concerned, this class is really at the mercy of the SynthModule implimentations, which needs to be as quick as they possibly can be.

A derived class might override this to do its own processing, but should call this base-class method as well.

Reimplemented from AudioDataLib::MidiSynth.

ReceiveMessage()

bool SampleBasedSynth::ReceiveMessage ( double deltaTimeSeconds, const uint8_t * message, uint64_t messageSize, Error & error )

overridevirtual

This method will be called when this destination is to receive the given MIDI message. Note that it's important that no heavy processing be done in this method (such as is the mentality when writing an audio callback), because the timing of MIDI message reception and processing can effect the quality of audio playback.

Parameters

[in]	deltaTimeSeconds	This is typically, but not always, set to the amount of time (in seconds) between now and the last time the function was called.
[in]	message	This is the payload of the message, which can be decoded using a derivative of the MidiData::Event class.
[in]	messageSize	This is the size of the payload in bytes.
[out]	error	This should be populated with error information if false is returned.

Returns

True should be returned on success; false otherwise.

Reimplemented from AudioDataLib::MidiMsgDestination.

SetChannelInstrument()

bool SampleBasedSynth::SetChannelInstrument	(	uint8_t	channel,
		uint8_t	instrument,
		Error &	error )

SetReverbEnabled()

void SampleBasedSynth::SetReverbEnabled

(

bool

reverbEnabled

)

SetWaveTableData()

void AudioDataLib::SampleBasedSynth::SetWaveTableData ( std::shared_ptr< WaveTableData > & waveTableData )

inline

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

• Source/Library/MIDI/SampleBasedSynth.h
• Source/Library/MIDI/SampleBasedSynth.cpp