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 #ifndef RealtimeAnalyser_h 26 #define RealtimeAnalyser_h 27 28 #include "platform/audio/AudioArray.h" 29 #include "wtf/Forward.h" 30 #include "wtf/Noncopyable.h" 31 #include "wtf/OwnPtr.h" 32 33 namespace WebCore { 34 35 class AudioBus; 36 class FFTFrame; 37 38 class RealtimeAnalyser FINAL { 39 WTF_MAKE_NONCOPYABLE(RealtimeAnalyser); 40 public: 41 RealtimeAnalyser(); 42 43 void reset(); 44 45 size_t fftSize() const { return m_fftSize; } 46 bool setFftSize(size_t); 47 48 unsigned frequencyBinCount() const { return m_fftSize / 2; } 49 50 void setMinDecibels(float k) { m_minDecibels = k; } 51 float minDecibels() const { return static_cast<float>(m_minDecibels); } 52 53 void setMaxDecibels(float k) { m_maxDecibels = k; } 54 float maxDecibels() const { return static_cast<float>(m_maxDecibels); } 55 56 void setSmoothingTimeConstant(float k) { m_smoothingTimeConstant = k; } 57 float smoothingTimeConstant() const { return static_cast<float>(m_smoothingTimeConstant); } 58 59 void getFloatFrequencyData(Float32Array*); 60 void getByteFrequencyData(Uint8Array*); 61 void getByteTimeDomainData(Uint8Array*); 62 63 // The audio thread writes input data here. 64 void writeInput(AudioBus*, size_t framesToProcess); 65 66 static const double DefaultSmoothingTimeConstant; 67 static const double DefaultMinDecibels; 68 static const double DefaultMaxDecibels; 69 70 static const unsigned DefaultFFTSize; 71 static const unsigned MinFFTSize; 72 static const unsigned MaxFFTSize; 73 static const unsigned InputBufferSize; 74 75 private: 76 // The audio thread writes the input audio here. 77 AudioFloatArray m_inputBuffer; 78 unsigned m_writeIndex; 79 80 size_t m_fftSize; 81 OwnPtr<FFTFrame> m_analysisFrame; 82 void doFFTAnalysis(); 83 84 // doFFTAnalysis() stores the floating-point magnitude analysis data here. 85 AudioFloatArray m_magnitudeBuffer; 86 AudioFloatArray& magnitudeBuffer() { return m_magnitudeBuffer; } 87 88 // A value between 0 and 1 which averages the previous version of m_magnitudeBuffer with the current analysis magnitude data. 89 double m_smoothingTimeConstant; 90 91 // The range used when converting when using getByteFrequencyData(). 92 double m_minDecibels; 93 double m_maxDecibels; 94 }; 95 96 } // namespace WebCore 97 98 #endif // RealtimeAnalyser_h 99
