Use a LADSPA plugin as an audio processor. More...

#include <AsyncAudioLADSPAPlugin.h>

Inheritance diagram for Async::AudioLADSPAPlugin:

Public Types
using	PortNumber = decltype(LADSPA_Descriptor::PortCount)

using	PluginIndex = unsigned long

using	UniqueID = unsigned long

Public Member Functions
	AudioLADSPAPlugin (const std::string &path, PluginIndex index)
	Constructor.

	AudioLADSPAPlugin (UniqueID id)
	Constructor.

	AudioLADSPAPlugin (const std::string &label)
	Constructor.

	AudioLADSPAPlugin (const AudioLADSPAPlugin &)=delete
	Disallow copy construction.

AudioLADSPAPlugin &	operator= (const AudioLADSPAPlugin &)=delete
	Disallow copy assignment.

	~AudioLADSPAPlugin (void)
	Destructor.

bool	initialize (void)
	Initialize the plugin.

PortNumber	findControlInputByName (const std::string &name)
	Find an input control port by name.

bool	setControl (PortNumber portno, LADSPA_Data val)
	Set a control input to the given value.

void	activate (void)
	Activate the plugin.

void	deactivate (void)
	Deactivate the plugin.

std::string	path (void) const
	Get the path to the plugin.

UniqueID	uniqueId (void) const
	Get the unique ID for the plugin.

std::string	label (void) const
	Get the unique label for the plugin.

std::string	name (void) const
	Get the name of the plugin.

std::string	maker (void) const
	Get information on the maker of the plugin.

std::string	copyright (void) const
	Get the copyright information for the plugin.

PortNumber	portCount (void) const
	Get the number of ports for the plugin.

bool	portIsControl (PortNumber portno) const
	Check if a port is a control port.

bool	portIsAudio (PortNumber portno) const
	Check if a port is an audio port.

bool	portIsInput (PortNumber portno) const
	Check if a port is an input port.

bool	portIsOutput (PortNumber portno) const
	Check if a port is an output port.

void	print (const std::string &prefix="")
	Print some useful information for the plugin.

Public Member Functions inherited from Async::AudioProcessor
	AudioProcessor (void)
	Default constuctor.

virtual	~AudioProcessor (void)
	Destructor.

int	writeSamples (const float *samples, int len)
	Write audio to the filter.

void	flushSamples (void)
	Order a flush of all samples.

void	resumeOutput (void)
	Resume output to the sink if previously stopped.

void	allSamplesFlushed (void)
	All samples have been flushed by the sink.

Public Member Functions inherited from Async::AudioSink
	AudioSink (void)
	Default constuctor.

virtual	~AudioSink (void)
	Destructor.

bool	registerSource (AudioSource *source)
	Register an audio source to provide samples to this sink.

void	unregisterSource (void)
	Unregister the previously registered audio source.

bool	isRegistered (void) const
	Check if an audio source has been registered.

AudioSource *	source (void) const
	Get the registered audio source.

Public Member Functions inherited from Async::AudioSource
	AudioSource (void)
	Default constuctor.

virtual	~AudioSource (void)
	Destructor.

bool	registerSink (AudioSink *sink, bool managed=false)
	Register an audio sink to provide samples to.

void	unregisterSink (void)
	Unregister the previously registered audio sink.

bool	isRegistered (void) const
	Check if an audio sink has been registered.

AudioSink *	sink (void) const
	Get the registered audio sink.

bool	sinkManaged (void) const
	Check if the sink is managed or not.

void	handleAllSamplesFlushed (void)
	The registered sink has flushed all samples.

Static Public Member Functions
static bool	findPluginsInDir (std::string dir)
	Find any LADSPA plugins in the given subdirectory.

static bool	findPlugins (void)
	Find LADSPA plugins in standard subdirectories.

Static Public Attributes
static constexpr PortNumber	npos = std::numeric_limits<PortNumber>::max()

Protected Member Functions
virtual void	processSamples (float dest, const float src, int count) override
	Process incoming samples and put them into the output buffer.

Protected Member Functions inherited from Async::AudioProcessor
void	setInputOutputSampleRate (int input_rate, int output_rate)
	Set the input and output sample rates.

Protected Member Functions inherited from Async::AudioSink
void	sourceResumeOutput (void)
	Tell the source that we are ready to accept more samples.

void	sourceAllSamplesFlushed (void)
	Tell the source that all samples have been flushed.

bool	setHandler (AudioSink *handler)
	Setup another sink to handle the incoming audio.

void	clearHandler (void)
	Clear a handler that was previously setup with setHandler.

AudioSink *	handler (void) const

Protected Member Functions inherited from Async::AudioSource
int	sinkWriteSamples (const float *samples, int len)

void	sinkFlushSamples (void)

bool	setHandler (AudioSource *handler)
	Setup another source to handle the outgoing audio.

AudioSource *	handler (void) const

void	clearHandler (void)
	Clear a handler that was previously setup with setHandler.

Detailed Description

Use a LADSPA plugin as an audio processor.

Author: Tobias Blomberg / SM0SVX

Date: 2023-12-09

This class is used to load a LADSPA plugin and use it as an audio processor.

#include <iostream>
#include <AsyncCppApplication.h>
#include <AsyncAudioIO.h>
#include <AsyncAudioLADSPAPlugin.h>
#include <AsyncFdWatch.h>
 
int main(void)
{
  Async::CppApplication app;
 
  Async::AudioIO audio_io("alsa:default", 0);
  audio_io.open(Async::AudioIO::MODE_RDWR);
  Async::AudioSource* prev_src = &audio_io;
 
  std::string label("tap_pitch");
  Async::AudioLADSPAPlugin p1(label);
  if (!p1.initialize())
  {
    std::cout << "*** ERROR: Could not instantiate LADSPA plugin instance "
                 "with label " << label << std::endl;
    exit(1);
  }
  p1.setControl(0, 4);
  p1.print();
  prev_src->registerSink(&p1);
  prev_src = &p1;
 
  label = "tap_vibrato";
  Async::AudioLADSPAPlugin p2(label);
  if (!p2.initialize())
  {
    std::cout << "*** ERROR: Could not instantiate LADSPA plugin instance "
                 "with label " << label << std::endl;
    exit(1);
  }
  p2.setControl(0, 10);
  p2.setControl(1, 10);
  p2.print();
  prev_src->registerSink(&p2);
  prev_src = &p2;
 
  prev_src->registerSink(&audio_io);
 
  app.exec();
 
  return 0;
}

Examples: AsyncAudioLADSPAPlugin_demo.cpp.

Definition at line 125 of file AsyncAudioLADSPAPlugin.h.

Member Typedef Documentation

◆ PluginIndex

using Async::AudioLADSPAPlugin::PluginIndex = unsigned long

Definition at line 129 of file AsyncAudioLADSPAPlugin.h.

◆ PortNumber

using Async::AudioLADSPAPlugin::PortNumber = decltype(LADSPA_Descriptor::PortCount)

Definition at line 128 of file AsyncAudioLADSPAPlugin.h.

◆ UniqueID

using Async::AudioLADSPAPlugin::UniqueID = unsigned long

Definition at line 130 of file AsyncAudioLADSPAPlugin.h.

Constructor & Destructor Documentation

◆ AudioLADSPAPlugin() [1/4]

Async::AudioLADSPAPlugin::AudioLADSPAPlugin	(	const std::string &	path,
		PluginIndex	index )

inline

Constructor.

Parameters

path	The full path of the plugin to load
index	The index of the plugin to instantiate

This constructor is normally not used directly unless there is a special requirement to load a specific LADSPA plugin file with a known plugin index.

Definition at line 172 of file AsyncAudioLADSPAPlugin.h.

◆ AudioLADSPAPlugin() [2/4]

Async::AudioLADSPAPlugin::AudioLADSPAPlugin ( UniqueID id )

Constructor.

Parameters

id	The plugin unique id to look for

Use this constructor for creating a LADSPA plugin instance if you know its unique ID. The easiest way normally is to use the label to find the plugin.

◆ AudioLADSPAPlugin() [3/4]

Async::AudioLADSPAPlugin::AudioLADSPAPlugin ( const std::string & label )

Constructor.

Parameters

label The plugin label to look for

This is the main constructor for creating a LADSPA plugin instance.

◆ AudioLADSPAPlugin() [4/4]

Async::AudioLADSPAPlugin::AudioLADSPAPlugin ( const AudioLADSPAPlugin & )

delete

Disallow copy construction.

◆ ~AudioLADSPAPlugin()

Async::AudioLADSPAPlugin::~AudioLADSPAPlugin ( void )

Destructor.

Member Function Documentation

◆ activate()

void Async::AudioLADSPAPlugin::activate ( void )

Activate the plugin.

Use this function to activate this plugin. Activation is done in the initialize function so manual activation is normally not needed. Read more about plugin activation in the LADSPA documentation.

◆ copyright()

std::string Async::AudioLADSPAPlugin::copyright ( void ) const

inline

Get the copyright information for the plugin.

Returns: Returns a string describing the copyright

Definition at line 292 of file AsyncAudioLADSPAPlugin.h.

◆ deactivate()

void Async::AudioLADSPAPlugin::deactivate ( void )

Deactivate the plugin.

Use this function to deactivate this plugin. Read more about plugin activation in the LADSPA documentation.

◆ findControlInputByName()

PortNumber Async::AudioLADSPAPlugin::findControlInputByName ( const std::string & name )

Find an input control port by name.

Parameters

name	The port namne to look for

Returns: Return the port number or "npos" if not found

◆ findPlugins()

static bool Async::AudioLADSPAPlugin::findPlugins ( void )

static

Find LADSPA plugins in standard subdirectories.

LADSPA plugins are typically installed in /usr/lib64/ladspa (on a 64 bit x86 system). This default value is adapted automatically to match the target system during compilation of the software.

If the LADSPA_PATH environment variable is set it will override the default path.

This function is called by the "label variant" of the constructor if the plugin index is empty.

◆ findPluginsInDir()

static bool Async::AudioLADSPAPlugin::findPluginsInDir ( std::string dir )

static

Find any LADSPA plugins in the given subdirectory.

Parameters

dir	The path to the directory to look in

This function will go through all files in the given subdirectory, reading any *.so files it can find and load them as LADSPA plugins. The plugins are not fully initialized in this process but rather just the necessary calls are made to extract enough information to determine if this is a plugin that is compatible with this class. Any plugin found to be usable is put in an index so that we later can find plugins using their label.

◆ initialize()

bool Async::AudioLADSPAPlugin::initialize ( void )

Initialize the plugin.

Returns: Return true on success or else false is returned

All loading, instantiation and initialization of the plugin is done in this function. The LADSPA activate call is called at the end of the function so it is directly ready to process audio when this function returns true. If the function returns false, it's not allowed to call any other functions so the object should be deleted as soon as possible.

Examples: AsyncAudioLADSPAPlugin_demo.cpp.

◆ label()

std::string Async::AudioLADSPAPlugin::label ( void ) const

inline

Get the unique label for the plugin.

Returns: Returns the unique label for the plugin

The label is what most often is used to find a specific plugin.

Definition at line 272 of file AsyncAudioLADSPAPlugin.h.

◆ maker()

std::string Async::AudioLADSPAPlugin::maker ( void ) const

inline

Get information on the maker of the plugin.

Returns: Returns a string describing the plugin author.

Definition at line 286 of file AsyncAudioLADSPAPlugin.h.

◆ name()

std::string Async::AudioLADSPAPlugin::name ( void ) const

inline

Get the name of the plugin.

Returns: Returns the name of the plugin

This function return the free text name/display name for the plugin.

Definition at line 280 of file AsyncAudioLADSPAPlugin.h.

◆ operator=()

AudioLADSPAPlugin & Async::AudioLADSPAPlugin::operator= ( const AudioLADSPAPlugin & )

delete

Disallow copy assignment.

◆ path()

std::string Async::AudioLADSPAPlugin::path ( void ) const

inline

Get the path to the plugin.

Returns: Returns the path to the plugin

Definition at line 256 of file AsyncAudioLADSPAPlugin.h.

◆ portCount()

PortNumber Async::AudioLADSPAPlugin::portCount ( void ) const

inline

Get the number of ports for the plugin.

Returns: Returns the total number of control/audio input/output ports

Definition at line 298 of file AsyncAudioLADSPAPlugin.h.

◆ portIsAudio()

bool Async::AudioLADSPAPlugin::portIsAudio ( PortNumber portno ) const

Check if a port is an audio port.

Returns: Returns true if this is an audio port

◆ portIsControl()

bool Async::AudioLADSPAPlugin::portIsControl ( PortNumber portno ) const

Check if a port is a control port.

Returns: Returns true if this is a control port

◆ portIsInput()

bool Async::AudioLADSPAPlugin::portIsInput ( PortNumber portno ) const

Check if a port is an input port.

Returns: Returns true if this is an input port

◆ portIsOutput()

bool Async::AudioLADSPAPlugin::portIsOutput ( PortNumber portno ) const

Check if a port is an output port.

Returns: Returns true if this is an output port

◆ print()

void Async::AudioLADSPAPlugin::print ( const std::string & prefix = "" )

Print some useful information for the plugin.

Examples: AsyncAudioLADSPAPlugin_demo.cpp.

◆ processSamples()

virtual void Async::AudioLADSPAPlugin::processSamples	(	float *	dest,
		const float *	src,
		int	count )

overrideprotectedvirtual

Process incoming samples and put them into the output buffer.

Parameters

dest	Destination buffer
src	Source buffer
count	Number of samples in the source buffer

This function should be reimplemented by the inheriting class to do the actual processing of the incoming samples. All samples must be processed, otherwise they are lost and the output buffer will contain garbage.

Implements Async::AudioProcessor.

◆ setControl()

bool Async::AudioLADSPAPlugin::setControl	(	PortNumber	portno,
		LADSPA_Data	val )

Set a control input to the given value.

Parameters

portno	The port number to set
val	The value to set

Examples: AsyncAudioLADSPAPlugin_demo.cpp.

◆ uniqueId()

UniqueID Async::AudioLADSPAPlugin::uniqueId ( void ) const

inline

Get the unique ID for the plugin.

Returns: Returns the unique ID of the plugin

All plugins have a unique ID which can be used to find it.

Definition at line 264 of file AsyncAudioLADSPAPlugin.h.

Member Data Documentation

◆ npos

PortNumber Async::AudioLADSPAPlugin::npos = std::numeric_limits<PortNumber>::max()

staticconstexpr

Definition at line 132 of file AsyncAudioLADSPAPlugin.h.

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

AsyncAudioLADSPAPlugin.h

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Detailed Description

Member Typedef Documentation

◆ PluginIndex

◆ PortNumber

◆ UniqueID

Constructor & Destructor Documentation

◆ AudioLADSPAPlugin() [1/4]

◆ AudioLADSPAPlugin() [2/4]

◆ AudioLADSPAPlugin() [3/4]

◆ AudioLADSPAPlugin() [4/4]

◆ ~AudioLADSPAPlugin()

Member Function Documentation

◆ activate()

◆ copyright()

◆ deactivate()

◆ findControlInputByName()

◆ findPlugins()

◆ findPluginsInDir()

◆ initialize()

◆ label()

◆ maker()

◆ name()

◆ operator=()

◆ path()

◆ portCount()

◆ portIsAudio()

◆ portIsControl()

◆ portIsInput()

◆ portIsOutput()

◆ print()

◆ processSamples()

◆ setControl()

◆ uniqueId()

Member Data Documentation

◆ npos