AudioDestinationNode.h   [plain text]

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

#include "AudioBus.h"
#include "AudioIOCallback.h"
#include "AudioNode.h"
#include <wtf/Function.h>

namespace WebCore {

class AudioContext;

class AudioDestinationNode : public AudioNode, public AudioIOCallback {
public:
    AudioDestinationNode(AudioContext&, float sampleRate);
    virtual ~AudioDestinationNode();
    
    // AudioNode   
    void process(size_t) override { }; // we're pulled by hardware so this is never called
    void reset() override { m_currentSampleFrame = 0; }
    
    // The audio hardware calls render() to get the next render quantum of audio into destinationBus.
    // It will optionally give us local/live audio input in sourceBus (if it's not 0).
    void render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames) override;

    size_t currentSampleFrame() const { return m_currentSampleFrame; }
    double currentTime() const { return currentSampleFrame() / static_cast<double>(sampleRate()); }

    virtual unsigned maxChannelCount() const { return 0; }

    // Enable local/live input for the specified device.
    virtual void enableInput(const String& inputDeviceId) = 0;

    virtual void startRendering() = 0;
    virtual void resume(WTF::Function<void ()>&&) { }
    virtual void suspend(WTF::Function<void ()>&&) { }
    virtual void close(WTF::Function<void ()>&&) { }

    virtual bool isPlaying() { return false; }
    void isPlayingDidChange() override;
    bool isPlayingAudio() const { return m_isEffectivelyPlayingAudio; }
    void setMuted(bool muted) { m_muted = muted; }

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

    void setIsSilent(bool);
    void updateIsEffectivelyPlayingAudio();

    // Counts the number of sample-frames processed by the destination.
    size_t m_currentSampleFrame;

    bool m_isSilent;
    bool m_isEffectivelyPlayingAudio;
    bool m_muted;
};

} // namespace WebCore