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28 #include "modules/webaudio/AudioNode.h"
29 #include "modules/webaudio/AudioParam.h"
30 #include "wtf/PassRefPtr.h"
31 #include "wtf/Threading.h"
37 // GainNode is an AudioNode with one input and one output which applies a gain (volume) change to the audio signal.
38 // De-zippering (smoothing) is applied when the gain value is changed dynamically.
40 class GainNode FINAL : public AudioNode {
42 static PassRefPtrWillBeRawPtr<GainNode> create(AudioContext* context, float sampleRate)
44 return adoptRefWillBeNoop(new GainNode(context, sampleRate));
48 virtual void process(size_t framesToProcess) OVERRIDE;
50 // Called in the main thread when the number of channels for the input may have changed.
51 virtual void checkNumberOfChannelsForInput(AudioNodeInput*) OVERRIDE;
53 // JavaScript interface
54 AudioParam* gain() { return m_gain.get(); }
56 virtual void trace(Visitor*) OVERRIDE;
59 virtual double tailTime() const OVERRIDE { return 0; }
60 virtual double latencyTime() const OVERRIDE { return 0; }
62 GainNode(AudioContext*, float sampleRate);
64 float m_lastGain; // for de-zippering
65 RefPtrWillBeMember<AudioParam> m_gain;
67 AudioFloatArray m_sampleAccurateGainValues;