1 | /* |
2 | * Copyright (C) 2010, Google Inc. All rights reserved. |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions |
6 | * are met: |
7 | * 1. Redistributions of source code must retain the above copyright |
8 | * notice, this list of conditions and the following disclaimer. |
9 | * 2. Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
11 | * documentation and/or other materials provided with the distribution. |
12 | * |
13 | * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY |
14 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
16 | * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
17 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
18 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
19 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON |
20 | * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
22 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
23 | */ |
24 | |
25 | #pragma once |
26 | |
27 | #include "AudioNode.h" |
28 | #include "AudioParam.h" |
29 | #include <wtf/Threading.h> |
30 | |
31 | namespace WebCore { |
32 | |
33 | class AudioContext; |
34 | |
35 | // GainNode is an AudioNode with one input and one output which applies a gain (volume) change to the audio signal. |
36 | // De-zippering (smoothing) is applied when the gain value is changed dynamically. |
37 | |
38 | class GainNode final : public AudioNode { |
39 | WTF_MAKE_ISO_ALLOCATED(GainNode); |
40 | public: |
41 | static Ref<GainNode> create(AudioContext& context, float sampleRate) |
42 | { |
43 | return adoptRef(*new GainNode(context, sampleRate)); |
44 | } |
45 | |
46 | // AudioNode |
47 | void process(size_t framesToProcess) override; |
48 | void reset() override; |
49 | |
50 | // Called in the main thread when the number of channels for the input may have changed. |
51 | void checkNumberOfChannelsForInput(AudioNodeInput*) override; |
52 | |
53 | // JavaScript interface |
54 | AudioParam* gain() { return m_gain.get(); } |
55 | |
56 | private: |
57 | double tailTime() const override { return 0; } |
58 | double latencyTime() const override { return 0; } |
59 | |
60 | GainNode(AudioContext&, float sampleRate); |
61 | |
62 | float m_lastGain; // for de-zippering |
63 | RefPtr<AudioParam> m_gain; |
64 | |
65 | AudioFloatArray m_sampleAccurateGainValues; |
66 | }; |
67 | |
68 | } // namespace WebCore |
69 | |