CompressorProcessor Class Reference

#include <CompressorProcessor.h>

Collaboration diagram for CompressorProcessor:

Classes
struct	FrameStats

Public Member Functions
	CompressorProcessor (const DynamicRangeProcessorSettings &settings={ CompressorSettings {} })
	CompressorProcessor (const CompressorProcessor &other)=delete
	~CompressorProcessor ()
void	ApplySettingsIfNeeded (const DynamicRangeProcessorSettings &settings)
void	Init (int sampleRate, int numChannels, int blockSize)
void	Reinit ()
const DynamicRangeProcessorSettings &	GetSettings () const
void	Process (const float *const *inBlock, float *const *outBlock, int blockLen)
const std::vector< std::vector< float > > &	GetDelayedInput () const
const FrameStats &	GetLastFrameStats () const
float	EvaluateTransferFunction (float inputDb) const

Static Public Member Functions
static float	GetMaxCompressionDb (const DynamicRangeProcessorSettings &settings)
static float	GetMakeupGainDb (const DynamicRangeProcessorSettings &settings)
static float	EvaluateTransferFunction (const DynamicRangeProcessorSettings &settings, float inputDb)

Private Member Functions
void	UpdateEnvelope (const float *const *inBlock, int blockLen)
void	CopyWithDelay (const float *const *inBlock, int blockLen)
void	ApplyEnvelope (float *const *outBlock, int blockLen, float &delayedInputMax, int &delayedInputMaxIndex)
bool	Initialized () const

Private Attributes
const std::unique_ptr< DanielRudrich::GainReductionComputer >	mGainReductionComputer
const std::unique_ptr< DanielRudrich::LookAheadGainReduction >	mLookAheadGainReduction
DynamicRangeProcessorSettings	mSettings
int	mSampleRate = 0
int	mNumChannels = 0
int	mBlockSize = 0
std::array< float, maxBlockSize >	mEnvelope
std::vector< std::vector< float > >	mDelayedInput
FrameStats	mLastFrameStats

Static Private Attributes
static constexpr auto	maxBlockSize = 512

Detailed Description

Definition at line 25 of file CompressorProcessor.h.

Constructor & Destructor Documentation

CompressorProcessor() [1/2]

CompressorProcessor::CompressorProcessor

(

const DynamicRangeProcessorSettings &

settings = {   CompressorSettings {} }

)

Definition at line 42 of file CompressorProcessor.cpp.

    : mGainReductionComputer { std::make_unique<
         DanielRudrich::GainReductionComputer>() }
    , mLookAheadGainReduction { std::make_unique<
         DanielRudrich::LookAheadGainReduction>() }
    , mSettings { settings }
{
}

CompressorProcessor() [2/2]

CompressorProcessor::CompressorProcessor ( const CompressorProcessor &  other )

delete

~CompressorProcessor()

CompressorProcessor::~CompressorProcessor ( )

default

Member Function Documentation

ApplyEnvelope()

void CompressorProcessor::ApplyEnvelope ( float *const *  outBlock, int  blockLen, float &  delayedInputMax, int &  delayedInputMaxIndex  )

private

Definition at line 181 of file CompressorProcessor.cpp.

{
   const auto makeupGainDb = mGainReductionComputer->getMakeUpGain();
   const auto d = mLookAheadGainReduction->getDelayInSamples();
   std::array<float, 2> chanAbsMax { 0.f, 0.f };
   std::array<int, 2> chanAbsMaxIndex { 0, 0 };
   for (auto i = 0; i < mNumChannels; ++i)
   {
      const auto in = mDelayedInput[i].data();
      for (auto j = 0; j < blockLen; ++j)
      {
         if (std::abs(in[j]) > chanAbsMax[i])
         {
            chanAbsMax[i] = std::abs(in[j]);
            chanAbsMaxIndex[i] = j;
         }
         out[i][j] =
            in[j] * std::pow(10.f, 0.05f * (mEnvelope[j] + makeupGainDb));
      }
      std::move(in + blockLen, in + blockLen + d, in);
   }
   const auto i = chanAbsMax[0] > chanAbsMax[1] ? 0 : 1;
   delayedInputAbsMax = chanAbsMax[i];
   delayedInputAbsMaxIndex = chanAbsMaxIndex[i];
}

References mDelayedInput, mEnvelope, mGainReductionComputer, mLookAheadGainReduction, and mNumChannels.

Referenced by Process().

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ApplySettingsIfNeeded()

void CompressorProcessor::ApplySettingsIfNeeded

(

const DynamicRangeProcessorSettings &

settings

)

Definition at line 54 of file CompressorProcessor.cpp.

{
   if (settings == mSettings)
      return;
 
   const auto lookaheadNeedsReinit =
      settings.lookaheadMs != mSettings.lookaheadMs;
   mSettings = settings;
 
   mGainReductionComputer->setThreshold(settings.inCompressionThreshDb);
   mGainReductionComputer->setKnee(settings.kneeWidthDb);
   mGainReductionComputer->setAttackTime(settings.attackMs / 1000);
   mGainReductionComputer->setReleaseTime(settings.releaseMs / 1000);
   mGainReductionComputer->setRatio(settings.compressionRatio);
   mGainReductionComputer->setMakeUpGain(GetMakeupGainDb(settings));
 
   if (lookaheadNeedsReinit)
   {
      mLookAheadGainReduction->setDelayTime(settings.lookaheadMs / 1000);
      Reinit();
   }
}

References GetMakeupGainDb(), DynamicRangeProcessorSettings::lookaheadMs, mGainReductionComputer, mLookAheadGainReduction, mSettings, Reinit(), and settings().

Referenced by CompressorInstance::InstanceProcess().

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CopyWithDelay()

void CompressorProcessor::CopyWithDelay ( const float *const *  inBlock, int  blockLen  )

private

Definition at line 174 of file CompressorProcessor.cpp.

{
   const auto d = mLookAheadGainReduction->getDelayInSamples();
   for (auto i = 0; i < mNumChannels; ++i)
      std::copy(in[i], in[i] + blockLen, mDelayedInput[i].data() + d);
}

References staffpad::vo::copy(), mDelayedInput, mLookAheadGainReduction, and mNumChannels.

Referenced by Process().

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EvaluateTransferFunction() [1/2]

float CompressorProcessor::EvaluateTransferFunction ( const DynamicRangeProcessorSettings &  settings, float  inputDb  )

static

Definition at line 34 of file CompressorProcessor.cpp.

{
   return DanielRudrich::GainReductionComputer::getCharacteristicSample(
      inputDb, settings.kneeWidthDb, settings.inCompressionThreshDb,
      settings.compressionRatio, GetMakeupGainDb(settings));
}

References DanielRudrich::GainReductionComputer::getCharacteristicSample(), GetMakeupGainDb(), and settings().

Referenced by anonymous_namespace{DynamicRangeProcessorTransferFunctionPanel.cpp}::DrawTransferFunction(), and GetMaxCompressionDb().

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EvaluateTransferFunction() [2/2]

float CompressorProcessor::EvaluateTransferFunction

(

float

inputDb

)

const

Definition at line 142 of file CompressorProcessor.cpp.

{
   return mGainReductionComputer->getCharacteristicSample(inputDb);
}

References mGainReductionComputer.

GetDelayedInput()

const std::vector< std::vector< float > > & CompressorProcessor::GetDelayedInput

(

)

const

Definition at line 131 of file CompressorProcessor.cpp.

{
   return mDelayedInput;
}

References mDelayedInput.

GetLastFrameStats()

const CompressorProcessor::FrameStats & CompressorProcessor::GetLastFrameStats

(

)

const

Definition at line 137 of file CompressorProcessor.cpp.

{
   return mLastFrameStats;
}

References mLastFrameStats.

GetMakeupGainDb()

float CompressorProcessor::GetMakeupGainDb ( const DynamicRangeProcessorSettings &  settings )

static

---

Audacity: A Digital Audio Editor

CompressorProcessor.cpp

Matthieu Hodgkinson

Definition at line 19 of file CompressorProcessor.cpp.

{
   return settings.outCompressionThreshDb - settings.inCompressionThreshDb;
}

References settings().

Referenced by ApplySettingsIfNeeded(), EvaluateTransferFunction(), and anonymous_namespace{CompressorInstance.cpp}::GetOutputDb().

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GetMaxCompressionDb()

float CompressorProcessor::GetMaxCompressionDb ( const DynamicRangeProcessorSettings &  settings )

static

Definition at line 25 of file CompressorProcessor.cpp.

{
   const auto tfEval = EvaluateTransferFunction(settings, 0);
   const auto netGain =
      settings.outCompressionThreshDb - settings.inCompressionThreshDb;
   return netGain - tfEval;
}

References EvaluateTransferFunction(), and settings().

Referenced by DynamicRangeProcessorEditor::PopulateOrExchange(), and TEST_CASE().

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GetSettings()

const DynamicRangeProcessorSettings & CompressorProcessor::GetSettings

(

)

const

Definition at line 86 of file CompressorProcessor.cpp.

{
   return mSettings;
}

References mSettings.

Init()

void CompressorProcessor::Init	(	int	sampleRate,
		int	numChannels,
		int	blockSize
	)

Definition at line 78 of file CompressorProcessor.cpp.

{
   mSampleRate = sampleRate;
   mNumChannels = numChannels;
   mBlockSize = std::min(blockSize, maxBlockSize);
   Reinit();
}

References maxBlockSize, mBlockSize, min(), mNumChannels, mSampleRate, Reinit(), and anonymous_namespace{ClipSegmentTest.cpp}::sampleRate.

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Initialized()

bool CompressorProcessor::Initialized ( ) const

private

Definition at line 232 of file CompressorProcessor.cpp.

{
   return mSampleRate != 0 && mNumChannels != 0 && mBlockSize != 0;
}

References mBlockSize, mNumChannels, and mSampleRate.

Referenced by Process(), and Reinit().

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Process()

void CompressorProcessor::Process	(	const float *const *	inBlock,
		float *const *	outBlock,
		int	blockLen
	)

Definition at line 91 of file CompressorProcessor.cpp.

{
   assert(Initialized());
   if (!Initialized())
      return;
 
   auto processed = 0;
   mLastFrameStats = {};
   std::vector<const float*> in(mNumChannels);
   std::vector<float*> out(mNumChannels);
   while (processed < blockLen)
   {
      for (auto i = 0; i < mNumChannels; ++i)
      {
         in[i] = inBlock[i] + processed;
         out[i] = outBlock[i] + processed;
      }
      const auto toProcess = std::min(blockLen - processed, mBlockSize);
      UpdateEnvelope(in.data(), toProcess);
      CopyWithDelay(in.data(), toProcess);
 
      float delayedInputAbsMax = 0;
      int delayedInputAbsMaxIndex = 0;
      ApplyEnvelope(
         out.data(), toProcess, delayedInputAbsMax, delayedInputAbsMaxIndex);
 
      const auto blockMaxDb = log2ToDb * FastLog2(delayedInputAbsMax);
      if (mLastFrameStats.maxInputSampleDb < blockMaxDb)
      {
         mLastFrameStats.maxInputSampleDb = blockMaxDb;
         mLastFrameStats.dbGainOfMaxInputSample =
            mEnvelope[delayedInputAbsMaxIndex];
      }
 
      processed += toProcess;
   }
}

References ApplyEnvelope(), CopyWithDelay(), CompressorProcessor::FrameStats::dbGainOfMaxInputSample, FastLog2(), Initialized(), log2ToDb, CompressorProcessor::FrameStats::maxInputSampleDb, mBlockSize, mEnvelope, min(), mLastFrameStats, mNumChannels, and UpdateEnvelope().

Referenced by CompressorInstance::InstanceProcess().

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Reinit()

void CompressorProcessor::Reinit

(

)

Definition at line 209 of file CompressorProcessor.cpp.

{
   if (!Initialized())
      // Not there yet.
      return;
   mGainReductionComputer->prepare(mSampleRate);
   // In this order: setDelayTime, then prepare:
   mLookAheadGainReduction->setDelayTime(mSettings.lookaheadMs / 1000);
   mLookAheadGainReduction->prepare(mSampleRate, mBlockSize);
   const auto maxDelay =
      std::max(compressorMaxLookaheadMs, limiterMaxLookaheadMs) * mSampleRate /
      1000;
   const auto d = mLookAheadGainReduction->getDelayInSamples();
   assert(d <= maxDelay);
   mDelayedInput.resize(mNumChannels);
   std::for_each(mDelayedInput.begin(), mDelayedInput.end(), [&](auto& v) {
      v.reserve(maxDelay + mBlockSize);
      v.resize(d + mBlockSize);
      std::fill(v.begin(), v.end(), 0.f);
   });
   std::fill(mEnvelope.begin(), mEnvelope.end(), 0.f);
}

References compressorMaxLookaheadMs, Initialized(), limiterMaxLookaheadMs, DynamicRangeProcessorSettings::lookaheadMs, mBlockSize, mDelayedInput, mEnvelope, mGainReductionComputer, mLookAheadGainReduction, mNumChannels, mSampleRate, and mSettings.

Referenced by ApplySettingsIfNeeded(), and Init().

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UpdateEnvelope()

void CompressorProcessor::UpdateEnvelope ( const float *const *  inBlock, int  blockLen  )

private

Definition at line 147 of file CompressorProcessor.cpp.

{
   // Fill mEnvelope with max of all in channels;
   for (auto i = 0; i < blockLen; ++i)
   {
      auto max = 0.f;
      for (auto j = 0; j < mNumChannels; ++j)
      {
         const auto x = std::abs(in[j][i]);
         if (x > max)
            max = x;
      }
      mEnvelope[i] = max;
   }
 
   // TODO: uses std::log10 ; use log2 optimization instead.
   mGainReductionComputer->computeGainInDecibelsFromSidechainSignal(
      mEnvelope.data(), mEnvelope.data(), blockLen);
 
   if (mSettings.lookaheadMs <= 0)
      return;
 
   mLookAheadGainReduction->pushSamples(mEnvelope.data(), blockLen);
   mLookAheadGainReduction->process();
   mLookAheadGainReduction->readSamples(mEnvelope.data(), blockLen);
}

References DynamicRangeProcessorSettings::lookaheadMs, mEnvelope, mGainReductionComputer, mLookAheadGainReduction, mNumChannels, and mSettings.

Referenced by Process().

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Member Data Documentation

maxBlockSize

constexpr auto CompressorProcessor::maxBlockSize = 512

staticconstexprprivate

Definition at line 66 of file CompressorProcessor.h.

Referenced by Init().

mBlockSize

int CompressorProcessor::mBlockSize = 0

private

Definition at line 75 of file CompressorProcessor.h.

Referenced by Init(), Initialized(), Process(), and Reinit().

mDelayedInput

std::vector<std::vector<float> > CompressorProcessor::mDelayedInput

private

Definition at line 78 of file CompressorProcessor.h.

Referenced by ApplyEnvelope(), CopyWithDelay(), GetDelayedInput(), and Reinit().

mEnvelope

std::array<float, maxBlockSize> CompressorProcessor::mEnvelope

private

Definition at line 76 of file CompressorProcessor.h.

Referenced by ApplyEnvelope(), Process(), Reinit(), and UpdateEnvelope().

mGainReductionComputer

const std::unique_ptr<DanielRudrich::GainReductionComputer> CompressorProcessor::mGainReductionComputer

private

Definition at line 69 of file CompressorProcessor.h.

Referenced by ApplyEnvelope(), ApplySettingsIfNeeded(), EvaluateTransferFunction(), Reinit(), and UpdateEnvelope().

mLastFrameStats

FrameStats CompressorProcessor::mLastFrameStats

private

Definition at line 83 of file CompressorProcessor.h.

Referenced by GetLastFrameStats(), and Process().

mLookAheadGainReduction

const std::unique_ptr<DanielRudrich::LookAheadGainReduction> CompressorProcessor::mLookAheadGainReduction

private

Definition at line 71 of file CompressorProcessor.h.

Referenced by ApplyEnvelope(), ApplySettingsIfNeeded(), CopyWithDelay(), Reinit(), and UpdateEnvelope().

mNumChannels

int CompressorProcessor::mNumChannels = 0

private

Definition at line 74 of file CompressorProcessor.h.

Referenced by ApplyEnvelope(), CopyWithDelay(), Init(), Initialized(), Process(), Reinit(), and UpdateEnvelope().

mSampleRate

int CompressorProcessor::mSampleRate = 0

private

Definition at line 73 of file CompressorProcessor.h.

Referenced by Init(), Initialized(), and Reinit().

mSettings

DynamicRangeProcessorSettings CompressorProcessor::mSettings

private

Definition at line 72 of file CompressorProcessor.h.

Referenced by ApplySettingsIfNeeded(), GetSettings(), Reinit(), and UpdateEnvelope().

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

• CompressorProcessor.h
• CompressorProcessor.cpp