GainNode.h   [plain text]

/*
 * Copyright (C) 2010, Google Inc. All rights reserved.
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#pragma once

#include "AudioNode.h"
#include "AudioParam.h"
#include <wtf/Threading.h>

namespace WebCore {

class AudioContext;

// GainNode is an AudioNode with one input and one output which applies a gain (volume) change to the audio signal.
// De-zippering (smoothing) is applied when the gain value is changed dynamically.

class GainNode final : public AudioNode {
public:
    static Ref<GainNode> create(AudioContext& context, float sampleRate)
    {
        return adoptRef(*new GainNode(context, sampleRate));
    }

    // AudioNode
    void process(size_t framesToProcess) override;
    void reset() override;

    // Called in the main thread when the number of channels for the input may have changed.
    void checkNumberOfChannelsForInput(AudioNodeInput*) override;

    // JavaScript interface
    AudioParam* gain() { return m_gain.get(); }

private:
    double tailTime() const override { return 0; }
    double latencyTime() const override { return 0; }

    GainNode(AudioContext&, float sampleRate);

    float m_lastGain; // for de-zippering
    RefPtr<AudioParam> m_gain;

    AudioFloatArray m_sampleAccurateGainValues;
};

} // namespace WebCore