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 HRTFPanner_h 26 #define HRTFPanner_h 27 28 #include "platform/audio/AudioDelayDSPKernel.h" 29 #include "platform/audio/FFTConvolver.h" 30 #include "platform/audio/HRTFDatabaseLoader.h" 31 #include "platform/audio/Panner.h" 32 33 namespace WebCore { 34 35 class PLATFORM_EXPORT HRTFPanner : public Panner { 36 public: 37 HRTFPanner(float sampleRate, HRTFDatabaseLoader*); 38 virtual ~HRTFPanner(); 39 40 // Panner 41 virtual void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess) OVERRIDE; 42 virtual void reset() OVERRIDE; 43 fftSize()44 size_t fftSize() const { return fftSizeForSampleRate(m_sampleRate); } 45 static size_t fftSizeForSampleRate(float sampleRate); 46 sampleRate()47 float sampleRate() const { return m_sampleRate; } 48 49 virtual double tailTime() const OVERRIDE; 50 virtual double latencyTime() const OVERRIDE; 51 52 private: 53 // Given an azimuth angle in the range -180 -> +180, returns the corresponding azimuth index for the database, 54 // and azimuthBlend which is an interpolation value from 0 -> 1. 55 int calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azimuthBlend); 56 57 RefPtr<HRTFDatabaseLoader> m_databaseLoader; 58 59 float m_sampleRate; 60 61 // We maintain two sets of convolvers for smooth cross-faded interpolations when 62 // then azimuth and elevation are dynamically changing. 63 // When the azimuth and elevation are not changing, we simply process with one of the two sets. 64 // Initially we use CrossfadeSelection1 corresponding to m_convolverL1 and m_convolverR1. 65 // Whenever the azimuth or elevation changes, a crossfade is initiated to transition 66 // to the new position. So if we're currently processing with CrossfadeSelection1, then 67 // we transition to CrossfadeSelection2 (and vice versa). 68 // If we're in the middle of a transition, then we wait until it is complete before 69 // initiating a new transition. 70 71 // Selects either the convolver set (m_convolverL1, m_convolverR1) or (m_convolverL2, m_convolverR2). 72 enum CrossfadeSelection { 73 CrossfadeSelection1, 74 CrossfadeSelection2 75 }; 76 77 CrossfadeSelection m_crossfadeSelection; 78 79 // azimuth/elevation for CrossfadeSelection1. 80 int m_azimuthIndex1; 81 double m_elevation1; 82 83 // azimuth/elevation for CrossfadeSelection2. 84 int m_azimuthIndex2; 85 double m_elevation2; 86 87 // A crossfade value 0 <= m_crossfadeX <= 1. 88 float m_crossfadeX; 89 90 // Per-sample-frame crossfade value increment. 91 float m_crossfadeIncr; 92 93 FFTConvolver m_convolverL1; 94 FFTConvolver m_convolverR1; 95 FFTConvolver m_convolverL2; 96 FFTConvolver m_convolverR2; 97 98 AudioDelayDSPKernel m_delayLineL; 99 AudioDelayDSPKernel m_delayLineR; 100 101 AudioFloatArray m_tempL1; 102 AudioFloatArray m_tempR1; 103 AudioFloatArray m_tempL2; 104 AudioFloatArray m_tempR2; 105 }; 106 107 } // namespace WebCore 108 109 #endif // HRTFPanner_h 110