Source/WebCore/Modules/webaudio/DynamicsCompressorNode.h

/*
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 * Copyright (C) 2020, Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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#pragma once

#include "AudioNode.h"
#include "AudioParam.h"
#include "DynamicsCompressorOptions.h"
#include <memory>

namespace WebCore {

class DynamicsCompressor;

class DynamicsCompressorNode final : public AudioNode {
    WTF_MAKE_ISO_ALLOCATED(DynamicsCompressorNode);
public:
    static ExceptionOr<Ref<DynamicsCompressorNode>> create(BaseAudioContext&, const DynamicsCompressorOptions& = { });

    ~DynamicsCompressorNode();

    // AudioNode
    void process(size_t framesToProcess) final;
    void processOnlyAudioParams(size_t framesToProcess) final;
    void initialize() final;
    void uninitialize() final;

    // Static compression curve parameters.
    AudioParam& threshold() { return m_threshold.get(); }
    AudioParam& knee() { return m_knee.get(); }
    AudioParam& ratio() { return m_ratio.get(); }
    AudioParam& attack() { return m_attack.get(); }
    AudioParam& release() { return m_release.get(); }

    // Amount by which the compressor is currently compressing the signal in decibels.
    float reduction() const { return m_reduction; }

    ExceptionOr<void> setChannelCount(unsigned) final;
    ExceptionOr<void> setChannelCountMode(ChannelCountMode) final;

protected:
    explicit DynamicsCompressorNode(BaseAudioContext&, const DynamicsCompressorOptions& = { });
    virtual void setReduction(float reduction) { m_reduction = reduction; }

private:
    double tailTime() const final;
    double latencyTime() const final;
    bool requiresTailProcessing() const final;

    std::unique_ptr<DynamicsCompressor> m_dynamicsCompressor;
    Ref<AudioParam> m_threshold;
    Ref<AudioParam> m_knee;
    Ref<AudioParam> m_ratio;
    Ref<AudioParam> m_attack;
    Ref<AudioParam> m_release;
    float m_reduction { 0 };
};

} // namespace WebCore