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

#include <NoiseReduction.h>

Inheritance diagram for EffectNoiseReduction:

Collaboration diagram for EffectNoiseReduction:

Classes
class	Dialog
	Dialog used with EffectNoiseReduction. More...

class	Settings

class	Statistics

class	Worker

Public Member Functions
	EffectNoiseReduction ()

virtual	~EffectNoiseReduction ()

ComponentInterfaceSymbol	GetSymbol () override

TranslatableString	GetDescription () override

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

int	ShowHostInterface (wxWindow &parent, const EffectDialogFactory &factory, bool forceModal=false) override
	An override still here for historical reasons, ignoring the factory. More...

bool	Init () override

bool	CheckWhetherSkipEffect () override

bool	Process () override

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

Public Member Functions inherited from Effect
	Effect ()

virtual	~Effect ()

PluginPath	GetPath () override

VendorSymbol	GetVendor () override

wxString	GetVersion () override

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

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

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

bool	IsLegacy () override

bool	SupportsRealtime () override
	Whether the effect supports realtime previewing (while audio is playing). More...

bool	SupportsAutomation () override
	Whether the effect can be used without the UI, in a macro. More...

bool	GetAutomationParameters (CommandParameters &parms) override
	Save current settings into parms. More...

bool	SetAutomationParameters (CommandParameters &parms) override
	Change settings to those stored in parms. More...

bool	LoadUserPreset (const RegistryPath &name) override
	Change settings to a user-named preset. More...

bool	SaveUserPreset (const RegistryPath &name) override
	Save current settings as a user-named preset. More...

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

bool	LoadFactoryPreset (int id) override
	Change settings to the preset whose name is `GetFactoryPresets()[id]` More...

bool	LoadFactoryDefaults () override
	Change settings back to "factory default". More...

bool	SetHost (EffectHostInterface *host) override

unsigned	GetAudioInCount () override

unsigned	GetAudioOutCount () override

int	GetMidiInCount () override

int	GetMidiOutCount () override

sampleCount	GetLatency () override
	Called for destructive, non-realtime effect computation. More...

size_t	GetTailSize () override

void	SetSampleRate (double rate) override

size_t	SetBlockSize (size_t maxBlockSize) override

size_t	GetBlockSize () const override

bool	ProcessInitialize (sampleCount totalLen, ChannelNames chanMap=NULL) override
	Called for destructive, non-realtime effect computation. More...

bool	ProcessFinalize () override
	Called for destructive, non-realtime effect computation. More...

size_t	ProcessBlock (float inBlock, float outBlock, size_t blockLen) override
	Called for destructive, non-realtime effect computation. More...

bool	RealtimeInitialize () override

bool	RealtimeAddProcessor (unsigned numChannels, float sampleRate) override

bool	RealtimeFinalize () override

bool	RealtimeSuspend () override

bool	RealtimeResume () noexcept override

bool	RealtimeProcessStart () override

size_t	RealtimeProcess (int group, float inbuf, float outbuf, size_t numSamples) override

bool	RealtimeProcessEnd () noexcept override

int	ShowClientInterface (wxWindow &parent, wxDialog &dialog, bool forceModal=false) override

bool	PopulateUI (ShuttleGui &S) final
	Adds controls to a panel that is given as the parent window of `S` More...

bool	IsGraphicalUI () override

bool	ValidateUI () override

bool	HideUI () override

bool	CloseUI () override

bool	CanExportPresets () override

void	ExportPresets () override

void	ImportPresets () override

bool	HasOptions () override

void	ShowOptions () override

EffectDefinitionInterface &	GetDefinition () override

double	GetDuration () override

NumericFormatSymbol	GetDurationFormat () override

virtual NumericFormatSymbol	GetSelectionFormat ()

void	SetDuration (double duration) override

RegistryPath	GetUserPresetsGroup (const RegistryPath &name) override

RegistryPath	GetCurrentSettingsGroup () override

RegistryPath	GetFactoryDefaultsGroup () override

virtual wxString	GetSavedStateGroup ()

unsigned	TestUIFlags (unsigned mask)

void	SetPresetParameters (const wxArrayString Names, const wxArrayString Values)

virtual bool	Startup (EffectUIClientInterface *client)

virtual bool	GetAutomationParametersAsString (wxString &parms)

virtual bool	SetAutomationParametersFromString (const wxString &parms)

virtual bool	IsBatchProcessing ()

virtual void	SetBatchProcessing (bool start)

bool	DoEffect (double projectRate, TrackList list, WaveTrackFactory factory, NotifyingSelectedRegion &selectedRegion, unsigned flags, wxWindow *pParent=nullptr, const EffectDialogFactory &dialogFactory={})

bool	Delegate (Effect &delegate, wxWindow &parent, const EffectDialogFactory &factory)

int	MessageBox (const TranslatableString &message, long style=DefaultMessageBoxStyle, const TranslatableString &titleStr={})

virtual bool	Startup ()

Public Member Functions inherited from EffectUIClientInterface
virtual	~EffectUIClientInterface ()

Public Member Functions inherited from EffectProcessor
virtual	~EffectProcessor ()

Public Member Functions inherited from EffectDefinitionInterface
virtual	~EffectDefinitionInterface ()

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

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

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

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

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

Public Member Functions inherited from ComponentInterface
virtual	~ComponentInterface ()

TranslatableString	GetName ()

virtual bool	DefineParams (ShuttleParams &WXUNUSED(S))

Public Member Functions inherited from EffectUIHostInterface
virtual	~EffectUIHostInterface ()

Public Member Functions inherited from EffectHostInterface
virtual	~EffectHostInterface ()

Static Public Attributes
static const ComponentInterfaceSymbol	Symbol { XO("Noise Reduction") }

Static Public Attributes inherited from Effect
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>")

Private Attributes
std::unique_ptr< Settings >	mSettings

std::unique_ptr< Statistics >	mStatistics

Friends
class	Dialog

Additional Inherited Members
Public Types inherited from Effect
enum	: long { DefaultMessageBoxStyle = wxOK \| wxCENTRE }

Static Public Member Functions inherited from Effect
static void	IncEffectCounter ()

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

Protected Member Functions inherited from Effect
bool	EnableApply (bool enable=true)

bool	EnablePreview (bool enable=true)

virtual bool	ProcessPass ()

virtual bool	InitPass1 ()

virtual bool	InitPass2 ()

virtual void	End ()

virtual double	CalcPreviewInputLength (double previewLength)

virtual void	Preview (bool dryOnly)

virtual void	PopulateOrExchange (ShuttleGui &S)

virtual bool	TransferDataToWindow ()

virtual bool	TransferDataFromWindow ()

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

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

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

int	GetNumWaveTracks ()

int	GetNumWaveGroups ()

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

void	SetLinearEffectFlag (bool linearEffectFlag)

void	SetPreviewFullSelectionFlag (bool previewDurationFlag)

bool	IsPreviewing ()

void	IncludeNotSelectedPreviewTracks (bool includeNotSelected)

void	CopyInputTracks (bool allSyncLockSelected=false)

std::shared_ptr< AddedAnalysisTrack >	AddAnalysisTrack (const wxString &name=wxString())

ModifiedAnalysisTrack	ModifyAnalysisTrack (const LabelTrack *pOrigTrack, const wxString &name=wxString())

void	ReplaceProcessedTracks (const bool bGoodResult)

Track *	AddToOutputTracks (const std::shared_ptr< Track > &t)

const TrackList *	inputTracks () const

const AudacityProject *	FindProject () const

Protected Attributes inherited from Effect
BasicUI::ProgressDialog *	mProgress = nullptr

double	mProjectRate

double	mSampleRate

WaveTrackFactory *	mFactory

std::shared_ptr< TrackList >	mOutputTracks

double	mT0

double	mT1

wxArrayString	mPresetNames

wxArrayString	mPresetValues

int	mPass

wxWeakRef< wxDialog >	mHostUIDialog
	This smart pointer tracks the lifetime of the dialog. More...

wxWeakRef< wxDialog >	mUIDialog
	This weak pointer may be the same as the above, or null. More...

wxWindow *	mUIParent

unsigned	mUIFlags { 0 }

sampleCount	mSampleCnt

Static Protected Attributes inherited from Effect
static int	nEffectsDone =0

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 18 of file NoiseReduction.h.

Constructor & Destructor Documentation

◆ EffectNoiseReduction()

EffectNoiseReduction::EffectNoiseReduction ( )

Definition at line 410 of file NoiseReduction.cpp.

 : mSettings(std::make_unique<EffectNoiseReduction::Settings>())
 {
    Init();
 }

References Init().

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◆ ~EffectNoiseReduction()

EffectNoiseReduction::~EffectNoiseReduction ( )

virtual

Definition at line 416 of file NoiseReduction.cpp.

417 {

418 }

Member Function Documentation

◆ CheckWhetherSkipEffect()

bool EffectNoiseReduction::CheckWhetherSkipEffect ( )

overridevirtual

Reimplemented from Effect.

Definition at line 444 of file NoiseReduction.cpp.

 {
    return false;
 }

◆ GetDescription()

TranslatableString EffectNoiseReduction::GetDescription ( )

overridevirtual

Reimplemented from Effect.

Definition at line 427 of file NoiseReduction.cpp.

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

References XO.

◆ GetSymbol()

ComponentInterfaceSymbol EffectNoiseReduction::GetSymbol ( )

overridevirtual

Reimplemented from Effect.

Definition at line 422 of file NoiseReduction.cpp.

 {
    return Symbol;
 }

References Symbol.

◆ GetType()

EffectType EffectNoiseReduction::GetType ( )

overridevirtual

Type determines how it behaves.

Reimplemented from Effect.

Definition at line 434 of file NoiseReduction.cpp.

 {
    return EffectTypeProcess;
 }

References EffectTypeProcess.

◆ Init()

bool EffectNoiseReduction::Init ( )

overridevirtual

Reimplemented from Effect.

Definition at line 439 of file NoiseReduction.cpp.

 {
    return true;
 }

Referenced by EffectNoiseReduction().

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◆ Process()

bool EffectNoiseReduction::Process ( )

overridevirtual

If Process() is not overridden, it uses ProcessInitialize(), ProcessBlock(), and ProcessFinalize() methods of EffectProcessor, and also GetLatency() to determine how many leading output samples to discard and how many extra samples to produce.

Reimplemented from Effect.

Definition at line 624 of file NoiseReduction.cpp.

 {
    // This same code will either reduce noise or profile it
  
    this->CopyInputTracks(); // Set up mOutputTracks.
  
    auto track = * (mOutputTracks->Selected< const WaveTrack >()).begin();
    if (!track)
       return false;
  
    // Initialize statistics if gathering them, or check for mismatched (advanced)
    // settings if reducing noise.
    if (mSettings->mDoProfile) {
       size_t spectrumSize = 1 + mSettings->WindowSize() / 2;
       mStatistics = std::make_unique<Statistics>
          (spectrumSize, track->GetRate(), mSettings->mWindowTypes);
    }
    else if (mStatistics->mWindowSize != mSettings->WindowSize()) {
       // possible only with advanced settings
       ::Effect::MessageBox(
          XO("You must specify the same window size for steps 1 and 2.") );
       return false;
    }
    else if (mStatistics->mWindowTypes != mSettings->mWindowTypes) {
       // A warning only
       ::Effect::MessageBox(
          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{ inWindowType, outWindowType,
       *this, *mSettings, *mStatistics
 #ifdef EXPERIMENTAL_SPECTRAL_EDITING
       , mF0, mF1
 #endif
    };
    bool bGoodResult = worker.Process(*mOutputTracks, mT0, mT1);
    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
    }
    this->ReplaceProcessedTracks(bGoodResult);
    return bGoodResult;
 }

References Effect::CopyInputTracks(), eWinFuncBlackman, eWinFuncHamming, eWinFuncHann, eWinFuncRectangular, Effect::MessageBox(), Effect::mOutputTracks, mSettings, mStatistics, Effect::mT0, Effect::mT1, Effect::ReplaceProcessedTracks(), anonymous_namespace{NoiseReduction.cpp}::WT_BLACKMAN_HANN, anonymous_namespace{NoiseReduction.cpp}::WT_HAMMING_HANN, anonymous_namespace{NoiseReduction.cpp}::WT_HAMMING_RECTANGULAR, anonymous_namespace{NoiseReduction.cpp}::WT_HANN_HANN, anonymous_namespace{NoiseReduction.cpp}::WT_HANN_RECTANGULAR, anonymous_namespace{NoiseReduction.cpp}::WT_RECTANGULAR_HANN, and XO.

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◆ ShowHostInterface()

int EffectNoiseReduction::ShowHostInterface	(	wxWindow &	parent,
		const EffectDialogFactory &	factory,
		bool	forceModal = `false`
	)

overridevirtual

An override still here for historical reasons, ignoring the factory.

We would like to make this effect behave more like others, but it does have its unusual two-pass nature. First choose and analyze an example of noise, then apply noise reduction to another selection. That is difficult to fit into the framework for managing settings of other effects.

Reimplemented from Effect.

Definition at line 454 of file NoiseReduction.cpp.

 {
    // to do: use forceModal correctly
  
    // Doesn't use the factory but substitutes its own dialog
  
    // We may want to twiddle the levels if we are setting
    // from an automation dialog
    return mSettings->PromptUser(this, parent,
       bool(mStatistics), forceModal);
 }

References mSettings, and mStatistics.

◆ TrackProgress()

bool Effect::TrackProgress

Definition at line 298 of file Effect.cpp.

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

Friends And Related Function Documentation

◆ Dialog

friend class Dialog

friend

Definition at line 53 of file NoiseReduction.h.

Member Data Documentation

◆ mSettings

std::unique_ptr<Settings> EffectNoiseReduction::mSettings

private

Definition at line 55 of file NoiseReduction.h.

Referenced by Process(), and ShowHostInterface().

◆ mStatistics

std::unique_ptr<Statistics> EffectNoiseReduction::mStatistics

private

Definition at line 56 of file NoiseReduction.h.

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

◆ Symbol

const ComponentInterfaceSymbol EffectNoiseReduction::Symbol { XO("Noise Reduction") }

static

Definition at line 20 of file NoiseReduction.h.

Referenced by GetSymbol().

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

Classes

Public Member Functions

Static Public Attributes

Private Attributes

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ EffectNoiseReduction()

◆ ~EffectNoiseReduction()

Member Function Documentation

◆ CheckWhetherSkipEffect()

◆ GetDescription()

◆ GetSymbol()

◆ GetType()

◆ Init()

◆ Process()

◆ ShowHostInterface()

◆ TrackProgress()

Friends And Related Function Documentation

◆ Dialog

Member Data Documentation

◆ mSettings

◆ mStatistics

◆ Symbol