DynamicsCompressorNode.cpp   [plain text]


/*
 * Copyright (C) 2011, Google Inc. All rights reserved.
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 *
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "DynamicsCompressorNode.h"

#include "AudioContext.h"
#include "AudioNodeInput.h"
#include "AudioNodeOutput.h"
#include "DynamicsCompressor.h"

// Set output to stereo by default.
static const unsigned defaultNumberOfOutputChannels = 2;

namespace WebCore {

DynamicsCompressorNode::DynamicsCompressorNode(AudioContext* context, float sampleRate)
    : AudioNode(context, sampleRate)
{
    addInput(adoptPtr(new AudioNodeInput(this)));
    addOutput(adoptPtr(new AudioNodeOutput(this, defaultNumberOfOutputChannels)));

    setNodeType(NodeTypeDynamicsCompressor);

    m_threshold = AudioParam::create("threshold", -24, -100, 0);
    m_knee = AudioParam::create("knee", 30, 0, 40);
    m_ratio = AudioParam::create("ratio", 12, 1, 20);
    m_reduction = AudioParam::create("reduction", 0, -20, 0);
    m_attack = AudioParam::create("attack", 0.003, 0, 1);
    m_release = AudioParam::create("release", 0.250, 0, 1);

    m_threshold->setContext(context);
    m_knee->setContext(context);
    m_ratio->setContext(context);
    m_reduction->setContext(context);
    m_attack->setContext(context);
    m_release->setContext(context);

    initialize();
}

DynamicsCompressorNode::~DynamicsCompressorNode()
{
    uninitialize();
}

void DynamicsCompressorNode::process(size_t framesToProcess)
{
    AudioBus* outputBus = output(0)->bus();
    ASSERT(outputBus);

    float threshold = m_threshold->value();
    float knee = m_knee->value();
    float ratio = m_ratio->value();
    float attack = m_attack->value();
    float release = m_release->value();

    m_dynamicsCompressor->setParameterValue(DynamicsCompressor::ParamThreshold, threshold);
    m_dynamicsCompressor->setParameterValue(DynamicsCompressor::ParamKnee, knee);
    m_dynamicsCompressor->setParameterValue(DynamicsCompressor::ParamRatio, ratio);
    m_dynamicsCompressor->setParameterValue(DynamicsCompressor::ParamAttack, attack);
    m_dynamicsCompressor->setParameterValue(DynamicsCompressor::ParamRelease, release);

    m_dynamicsCompressor->process(input(0)->bus(), outputBus, framesToProcess);

    float reduction = m_dynamicsCompressor->parameterValue(DynamicsCompressor::ParamReduction);
    m_reduction->setValue(reduction);
}

void DynamicsCompressorNode::reset()
{
    m_dynamicsCompressor->reset();
}

void DynamicsCompressorNode::initialize()
{
    if (isInitialized())
        return;

    AudioNode::initialize();    
    m_dynamicsCompressor = adoptPtr(new DynamicsCompressor(sampleRate(), defaultNumberOfOutputChannels));
}

void DynamicsCompressorNode::uninitialize()
{
    if (!isInitialized())
        return;

    m_dynamicsCompressor.clear();
    AudioNode::uninitialize();
}

double DynamicsCompressorNode::tailTime() const
{
    return m_dynamicsCompressor->tailTime();
}

double DynamicsCompressorNode::latencyTime() const
{
    return m_dynamicsCompressor->latencyTime();
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)