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