A two-pass effect to reduce background noise. More...

#include <NoiseReductionBase.h>

Inheritance diagram for NoiseReductionBase:

Collaboration diagram for NoiseReductionBase:

Classes
class	Settings

class	Statistics

class	Worker

Public Member Functions
	NoiseReductionBase ()

virtual	~NoiseReductionBase ()

ComponentInterfaceSymbol	GetSymbol () const override

TranslatableString	GetDescription () const override

EffectType	GetType () const override
	Type determines how it behaves. More...

bool	Process (EffectInstance &instance, EffectSettings &settings) override

bool	TrackProgress (int whichTrack, double frac, const TranslatableString &={}) const

Public Member Functions inherited from StatefulEffect
	~StatefulEffect () override

std::shared_ptr< EffectInstance >	MakeInstance () const override
	Make an object maintaining short-term state of an Effect. More...

Public Member Functions inherited from StatefulEffectBase
virtual bool	Init ()

virtual bool	Process (EffectInstance &instance, EffectSettings &settings)=0

virtual bool	RealtimeInitialize (EffectSettings &settings, double sampleRate)

virtual bool	RealtimeAddProcessor (EffectSettings &settings, EffectOutputs *pOutputs, unsigned numChannels, float sampleRate)

virtual bool	RealtimeSuspend ()

virtual bool	RealtimeResume ()

virtual bool	RealtimeProcessStart (MessagePackage &package)
	settings are possibly changed, since last call, by an asynchronous dialog More...

virtual size_t	RealtimeProcess (size_t group, EffectSettings &settings, const float const inBuf, float const outBuf, size_t numSamples)

virtual bool	RealtimeProcessEnd (EffectSettings &settings) noexcept
	settings can be updated to let a dialog change appearance at idle More...

virtual bool	RealtimeFinalize (EffectSettings &settings) noexcept

virtual size_t	SetBlockSize (size_t maxBlockSize)

virtual size_t	GetBlockSize () const

virtual unsigned	GetAudioInCount () const
	How many input buffers to allocate at once. More...

virtual unsigned	GetAudioOutCount () const
	How many output buffers to allocate at once. More...

virtual sampleCount	GetLatency () const

virtual bool	NeedsDither () const

virtual bool	ProcessInitialize (EffectSettings &settings, double sampleRate, ChannelNames chanMap=nullptr)

virtual bool	ProcessFinalize () noexcept

Public Member Functions inherited from Effect
	Effect ()

virtual	~Effect ()

PluginPath	GetPath () const override

bool	VisitSettings (SettingsVisitor &visitor, EffectSettings &settings) override

bool	VisitSettings (ConstSettingsVisitor &visitor, const EffectSettings &settings) const override

ComponentInterfaceSymbol	GetSymbol () const override

VendorSymbol	GetVendor () const override

wxString	GetVersion () const override

TranslatableString	GetDescription () const override

EffectFamilySymbol	GetFamily () const override
	Report identifier and user-visible name of the effect protocol. More...

bool	IsInteractive () const override
	Whether the effect needs a dialog for entry of settings. More...

bool	IsDefault () const override
	Whether the effect sorts "above the line" in the menus. More...

RealtimeSince	RealtimeSupport () const override
	Since which version of Audacity has the effect supported realtime? More...

bool	SupportsAutomation () const override
	Whether the effect has any automatable controls. More...

bool	SaveSettings (const EffectSettings &settings, CommandParameters &parms) const override
	Store settings as keys and values. More...

bool	LoadSettings (const CommandParameters &parms, EffectSettings &settings) const override
	Restore settings from keys and values. More...

OptionalMessage	LoadUserPreset (const RegistryPath &name, EffectSettings &settings) const override

bool	SaveUserPreset (const RegistryPath &name, const EffectSettings &settings) const override
	Save settings in the configuration file as a user-named preset. More...

RegistryPaths	GetFactoryPresets () const override
	Report names of factory presets. More...

OptionalMessage	LoadFactoryPreset (int id, EffectSettings &settings) const override

OptionalMessage	LoadFactoryDefaults (EffectSettings &settings) const override

virtual const EffectParameterMethods &	Parameters () const

bool	CanExportPresets () const override
	Whether the effect supports export of presets to files, and importing too. More...

bool	HasOptions () const override

const EffectSettingsManager &	GetDefinition () const override

virtual NumericFormatID	GetSelectionFormat ()

bool	SaveSettingsAsString (const EffectSettings &settings, wxString &parms) const override

OptionalMessage	LoadSettingsFromString (const wxString &parms, EffectSettings &settings) const override

bool	IsBatchProcessing () const override

void	SetBatchProcessing () override

void	UnsetBatchProcessing () override

unsigned	TestUIFlags (unsigned mask)

bool	Delegate (Effect &delegate, EffectSettings &settings, InstanceFinder finder={})
	Re-invoke DoEffect on another Effect object that implements the work. More...

Public Member Functions inherited from EffectBase
	EffectBase ()

	~EffectBase () override

bool	IsLinearEffect () const

bool	PreviewsFullSelection () const

void	SetTracks (TrackList *pTracks)

double	GetDefaultDuration ()

virtual std::any	BeginPreview (const EffectSettings &settings)
	Called when Preview() starts, to allow temporary effect state changes. More...

bool	DoEffect (EffectSettings &settings, const InstanceFinder &finder, double projectRate, TrackList list, WaveTrackFactory factory, NotifyingSelectedRegion &selectedRegion, unsigned flags, const EffectSettingsAccessPtr &pAccess) override

virtual double	CalcPreviewInputLength (const EffectSettings &settings, double previewLength) const =0

void	CountWaveTracks ()

Public Member Functions inherited from EffectPlugin
EffectPlugin &	operator= (EffectPlugin &)=delete

virtual	~EffectPlugin ()

virtual bool	HasOptions () const =0

virtual bool	CanExportPresets () const =0
	Whether the effect supports export of presets to files, and importing too. More...

virtual const EffectSettingsManager &	GetDefinition () const =0

virtual bool	SaveSettingsAsString (const EffectSettings &settings, wxString &parms) const =0

virtual OptionalMessage	LoadSettingsFromString (const wxString &parms, EffectSettings &settings) const =0

virtual bool	IsBatchProcessing () const =0

virtual void	SetBatchProcessing ()=0

virtual void	UnsetBatchProcessing ()=0

virtual bool	DoEffect (EffectSettings &settings, const InstanceFinder &finder, double projectRate, TrackList list, WaveTrackFactory factory, NotifyingSelectedRegion &selectedRegion, unsigned flags, const EffectSettingsAccessPtr &pAccess=nullptr)=0

Public Member Functions inherited from EffectInstanceFactory
virtual	~EffectInstanceFactory ()

virtual std::shared_ptr< EffectInstance >	MakeInstance () const =0
	Make an object maintaining short-term state of an Effect. More...

Public Member Functions inherited from EffectSettingsManager
virtual	~EffectSettingsManager ()

virtual bool	VisitSettings (SettingsVisitor &visitor, EffectSettings &settings)

virtual bool	VisitSettings (ConstSettingsVisitor &visitor, const EffectSettings &settings) const

virtual EffectSettings	MakeSettings () const

virtual bool	CopySettingsContents (const EffectSettings &src, EffectSettings &dst) const
	Update one settings object from another. More...

virtual std::unique_ptr< EffectOutputs >	MakeOutputs () const
	Produce an object to hold values to send to effect output meters. More...

Public Member Functions inherited from EffectDefinitionInterface
virtual	~EffectDefinitionInterface ()

virtual EffectType	GetType () const =0
	Type determines how it behaves. More...

virtual EffectType	GetClassification () const
	Determines which menu it appears in; default same as GetType(). More...

virtual EffectFamilySymbol	GetFamily () const =0
	Report identifier and user-visible name of the effect protocol. More...

virtual bool	IsInteractive () const =0
	Whether the effect needs a dialog for entry of settings. More...

virtual bool	IsDefault () const =0
	Whether the effect sorts "above the line" in the menus. More...

virtual RealtimeSince	RealtimeSupport () const =0
	Since which version of Audacity has the effect supported realtime? More...

bool	SupportsRealtime () const

virtual bool	SupportsAutomation () const =0
	Whether the effect has any automatable controls. More...

virtual bool	EnablesDebug () const
	Whether the effect dialog should have a Debug button; default, always false. More...

virtual ManualPageID	ManualPage () const
	Name of a page in the Audacity alpha manual, default is empty. More...

virtual FilePath	HelpPage () const
	Fully qualified local help file name, default is empty. More...

virtual bool	IsHiddenFromMenus () const
	Default is false. More...

Public Member Functions inherited from ComponentInterface
virtual	~ComponentInterface ()

virtual PluginPath	GetPath () const =0

virtual ComponentInterfaceSymbol	GetSymbol () const =0

virtual VendorSymbol	GetVendor () const =0

virtual wxString	GetVersion () const =0

virtual TranslatableString	GetDescription () const =0

TranslatableString	GetName () const

Static Public Attributes
static const ComponentInterfaceSymbol	Symbol

Static Public Attributes inherited from EffectPlugin
static const wxString	kUserPresetIdent = wxT("User Preset:")

static const wxString	kFactoryPresetIdent = wxT("Factory Preset:")

static const wxString	kCurrentSettingsIdent = wxT("<Current Settings>")

static const wxString	kFactoryDefaultsIdent = wxT("<Factory Defaults>")

Protected Attributes
std::unique_ptr< Settings >	mSettings

std::unique_ptr< Statistics >	mStatistics

Protected Attributes inherited from EffectBase
double	mF0 {}

double	mF1 {}

wxArrayString	mPresetNames

unsigned	mUIFlags { 0 }

Additional Inherited Members
Public Types inherited from StatefulEffectBase
using	MessagePackage = EffectInstance::MessagePackage

Public Types inherited from EffectPlugin
using	EffectSettingsAccessPtr = std::shared_ptr< EffectSettingsAccess >

using	InstancePointer = std::shared_ptr< EffectInstanceEx >

using	InstanceFinder = std::function< std::optional< InstancePointer >(EffectSettings &settings) >

Public Types inherited from EffectDefinitionInterface
enum class	RealtimeSince : unsigned { Never , After_3_1 , Always }
	In which versions of Audacity was an effect realtime capable? More...

Static Public Member Functions inherited from Effect
static Effect *	FetchParameters (Effect &e, EffectSettings &)

Static Public Member Functions inherited from EffectBase
static std::optional< InstancePointer >	FindInstance (EffectPlugin &plugin)

static InstanceFinder	DefaultInstanceFinder (EffectPlugin &plugin)

Static Public Member Functions inherited from EffectDefinitionInterface
static Identifier	GetSquashedName (const Identifier &ident)
	A utility that strips spaces and CamelCases a name. More...

Public Attributes inherited from EffectBase
std::shared_ptr< TrackList >	mTracks {}

int	mNumTracks {}

BasicUI::ProgressDialog *	mProgress {}

double	mProjectRate {}

WaveTrackFactory *	mFactory {}

double	mT0 {}

double	mT1 {}

bool	mIsPreview { false }

Protected Member Functions inherited from Effect
bool	CheckWhetherSkipEffect (const EffectSettings &settings) const override
	Default implementation returns false. More...

double	CalcPreviewInputLength (const EffectSettings &settings, double previewLength) const override
	Default implementation returns `previewLength` More...

bool	TotalProgress (double frac, const TranslatableString &={}) const

bool	TrackProgress (int whichTrack, double frac, const TranslatableString &={}) const

bool	TrackGroupProgress (int whichGroup, double frac, const TranslatableString &={}) const

int	GetNumWaveTracks () const

int	GetNumWaveGroups () const

void	GetBounds (const WaveTrack &track, sampleCount start, sampleCount len)

Protected Member Functions inherited from EffectBase
virtual bool	CheckWhetherSkipEffect (const EffectSettings &settings) const =0
	After Init(), tell whether Process() should be skipped. More...

void	SetLinearEffectFlag (bool linearEffectFlag)

void	SetPreviewFullSelectionFlag (bool previewDurationFlag)

bool	IsPreviewing () const

const TrackList *	inputTracks () const

const AudacityProject *	FindProject () const

Detailed Description

A two-pass effect to reduce background noise.

The first pass is done over just noise. For each windowed sample of the sound, we take a FFT and then statistics are tabulated for each frequency band.

During the noise reduction phase, we start by setting a gain control for each frequency band such that if the sound has exceeded the previously-determined threshold, the gain is set to 0 dB, otherwise the gain is set lower (e.g. -18 dB), to suppress the noise. Then time-smoothing is applied so that the gain for each frequency band moves slowly, and then frequency-smoothing is applied so that a single frequency is never suppressed or boosted in isolation. Lookahead is employed; this effect is not designed for real-time but if it were, there would be a significant delay.

The gain controls are applied to the complex FFT of the signal, and then the inverse FFT is applied. A Hann window may be applied (depending on the advanced window types setting), and then the output signal is then pieced together using overlap/add.

Definition at line 22 of file NoiseReductionBase.h.

Constructor & Destructor Documentation

◆ NoiseReductionBase()

NoiseReductionBase::NoiseReductionBase ( )

Definition at line 292 of file NoiseReductionBase.cpp.

    : mSettings(std::make_unique<NoiseReductionBase::Settings>())
{
}

◆ ~NoiseReductionBase()

NoiseReductionBase::~NoiseReductionBase ( )

virtual

Definition at line 297 of file NoiseReductionBase.cpp.

298{

299}

Member Function Documentation

◆ GetDescription()

TranslatableString NoiseReductionBase::GetDescription ( ) const

overridevirtual

Implements ComponentInterface.

Definition at line 308 of file NoiseReductionBase.cpp.

{
   return XO("Removes background noise such as fans, tape noise, or hums");
}

References XO().

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◆ GetSymbol()

ComponentInterfaceSymbol NoiseReductionBase::GetSymbol ( ) const

overridevirtual

Implements ComponentInterface.

Definition at line 303 of file NoiseReductionBase.cpp.

{
   return Symbol;
}

References Symbol.

◆ GetType()

EffectType NoiseReductionBase::GetType ( ) const

overridevirtual

Type determines how it behaves.

Implements EffectDefinitionInterface.

Definition at line 315 of file NoiseReductionBase.cpp.

{
   return EffectTypeProcess;
}

References EffectTypeProcess.

Referenced by Process().

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◆ Process()

bool NoiseReductionBase::Process	(	EffectInstance &	instance,
		EffectSettings &	settings
	)

overridevirtual

Implements StatefulEffectBase.

Definition at line 464 of file NoiseReductionBase.cpp.

{
   // This same code will either reduce noise or profile it
 
   EffectOutputTracks outputs { *mTracks, GetType(), { { mT0, mT1 } } };
 
   auto track = *(outputs.Get().Selected<const WaveTrack>()).begin();
   if (!track)
      return false;
 
   const auto stepsPerWindow = mSettings->StepsPerWindow();
   const auto stepSize = mSettings->WindowSize() / stepsPerWindow;
 
   // Initialize statistics if gathering them, or check for mismatched
   // (advanced) settings if reducing noise.
   if (mSettings->mDoProfile)
   {
      const auto spectrumSize = mSettings->SpectrumSize();
      mStatistics = std::make_unique<Statistics>(
         spectrumSize, track->GetRate(), mSettings->mWindowTypes);
   }
   else if (mStatistics->mWindowSize != mSettings->WindowSize())
   {
      // possible only with advanced settings
      BasicUI::ShowMessageBox(
         XO("You must specify the same window size for steps 1 and 2."));
      return false;
   }
   else if (mStatistics->mWindowTypes != mSettings->mWindowTypes)
   {
      // A warning only
      BasicUI::ShowMessageBox(
         XO("Warning: window types are not the same as for profiling."));
   }
 
   eWindowFunctions inWindowType, outWindowType;
   switch (mSettings->mWindowTypes)
   {
   case WT_RECTANGULAR_HANN:
      inWindowType = eWinFuncRectangular;
      outWindowType = eWinFuncHann;
      break;
   case WT_HANN_RECTANGULAR:
      inWindowType = eWinFuncHann;
      outWindowType = eWinFuncRectangular;
      break;
   case WT_BLACKMAN_HANN:
      inWindowType = eWinFuncBlackman;
      outWindowType = eWinFuncHann;
      break;
   case WT_HAMMING_RECTANGULAR:
      inWindowType = eWinFuncHamming;
      outWindowType = eWinFuncRectangular;
      break;
   case WT_HAMMING_HANN:
      inWindowType = eWinFuncHamming;
      outWindowType = eWinFuncHann;
      break;
   default:
      wxASSERT(false);
      [[fallthrough]];
   case WT_HANN_HANN:
      inWindowType = outWindowType = eWinFuncHann;
      break;
   }
   Worker worker { *this, *mSettings, *mStatistics
#ifdef SPECTRAL_EDIT_NOISE_REDUCTION
                   ,
                   mF0, mF1
#endif
   };
   bool bGoodResult =
      worker.Process(inWindowType, outWindowType, outputs.Get(), mT0, mT1);
   const auto wasProfile = mSettings->mDoProfile;
   if (mSettings->mDoProfile)
   {
      if (bGoodResult)
         mSettings->mDoProfile =
            false; // So that "repeat last effect" will reduce noise
      else
         mStatistics.reset(); // So that profiling must be done again before
                              // noise reduction
   }
   if (bGoodResult && !wasProfile)
      outputs.Commit();
 
   return bGoodResult;
}

References eWinFuncBlackman, eWinFuncHamming, eWinFuncHann, eWinFuncRectangular, GetType(), EffectBase::mF0, EffectBase::mF1, mSettings, mStatistics, EffectBase::mT0, EffectBase::mT1, EffectBase::mTracks, BasicUI::ShowMessageBox(), anonymous_namespace{NoiseReductionBase.cpp}::WT_BLACKMAN_HANN, anonymous_namespace{NoiseReductionBase.cpp}::WT_HAMMING_HANN, anonymous_namespace{NoiseReductionBase.cpp}::WT_HAMMING_RECTANGULAR, anonymous_namespace{NoiseReductionBase.cpp}::WT_HANN_HANN, anonymous_namespace{NoiseReductionBase.cpp}::WT_HANN_RECTANGULAR, anonymous_namespace{NoiseReductionBase.cpp}::WT_RECTANGULAR_HANN, and XO().

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◆ TrackProgress()

bool Effect::TrackProgress	(	int	whichTrack,
		double	frac,
		const TranslatableString &	msg = `{}`
	)		const

Definition at line 131 of file Effect.cpp.

{
   auto updateResult = (mProgress ?
      mProgress->Poll((whichTrack + frac) * 1000,
         (double) mNumTracks * 1000, msg) :
      BasicUI::ProgressResult::Success);
   return (updateResult != BasicUI::ProgressResult::Success);
}

References PluginSettings::GetConfig(), Effect::GetDefinition(), Effect::LoadSettingsFromString(), name, PluginSettings::Private, settings(), and wxT().

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Member Data Documentation

◆ mSettings

std::unique_ptr<Settings> NoiseReductionBase::mSettings

protected

Definition at line 103 of file NoiseReductionBase.h.

Referenced by NoiseReductionBase::Worker::ApplyFreqSmoothing(), NoiseReductionBase::Worker::GatherStatistics(), Process(), NoiseReductionBase::Worker::Process(), NoiseReductionBase::Worker::ReduceNoise(), and EffectNoiseReduction::ShowHostInterface().

◆ mStatistics

std::unique_ptr<Statistics> NoiseReductionBase::mStatistics

protected

Definition at line 104 of file NoiseReductionBase.h.

Referenced by NoiseReductionBase::Worker::Classify(), NoiseReductionBase::Worker::FinishTrackStatistics(), NoiseReductionBase::Worker::GatherStatistics(), Process(), NoiseReductionBase::Worker::Process(), and EffectNoiseReduction::ShowHostInterface().

◆ Symbol

const ComponentInterfaceSymbol NoiseReductionBase::Symbol

static

Initial value:

{ XO(

"Noise Reduction") }

Definition at line 25 of file NoiseReductionBase.h.

Referenced by GetSymbol().

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

Classes

Public Member Functions

Static Public Attributes

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ NoiseReductionBase()

◆ ~NoiseReductionBase()

Member Function Documentation

◆ GetDescription()

◆ GetSymbol()

◆ GetType()

◆ Process()

◆ TrackProgress()

Member Data Documentation

◆ mSettings

◆ mStatistics

◆ Symbol