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 33namespace blink { 34 35class PLATFORM_EXPORT HRTFPanner FINAL : public Panner { 36public: 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 44 size_t fftSize() const { return fftSizeForSampleRate(m_sampleRate); } 45 static size_t fftSizeForSampleRate(float sampleRate); 46 47 float sampleRate() const { return m_sampleRate; } 48 49 virtual double tailTime() const OVERRIDE; 50 virtual double latencyTime() const OVERRIDE; 51 52 virtual void trace(Visitor*) OVERRIDE; 53 54private: 55 // Given an azimuth angle in the range -180 -> +180, returns the corresponding azimuth index for the database, 56 // and azimuthBlend which is an interpolation value from 0 -> 1. 57 int calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azimuthBlend); 58 59 Member<HRTFDatabaseLoader> m_databaseLoader; 60 61 float m_sampleRate; 62 63 // We maintain two sets of convolvers for smooth cross-faded interpolations when 64 // then azimuth and elevation are dynamically changing. 65 // When the azimuth and elevation are not changing, we simply process with one of the two sets. 66 // Initially we use CrossfadeSelection1 corresponding to m_convolverL1 and m_convolverR1. 67 // Whenever the azimuth or elevation changes, a crossfade is initiated to transition 68 // to the new position. So if we're currently processing with CrossfadeSelection1, then 69 // we transition to CrossfadeSelection2 (and vice versa). 70 // If we're in the middle of a transition, then we wait until it is complete before 71 // initiating a new transition. 72 73 // Selects either the convolver set (m_convolverL1, m_convolverR1) or (m_convolverL2, m_convolverR2). 74 enum CrossfadeSelection { 75 CrossfadeSelection1, 76 CrossfadeSelection2 77 }; 78 79 CrossfadeSelection m_crossfadeSelection; 80 81 // azimuth/elevation for CrossfadeSelection1. 82 int m_azimuthIndex1; 83 double m_elevation1; 84 85 // azimuth/elevation for CrossfadeSelection2. 86 int m_azimuthIndex2; 87 double m_elevation2; 88 89 // A crossfade value 0 <= m_crossfadeX <= 1. 90 float m_crossfadeX; 91 92 // Per-sample-frame crossfade value increment. 93 float m_crossfadeIncr; 94 95 FFTConvolver m_convolverL1; 96 FFTConvolver m_convolverR1; 97 FFTConvolver m_convolverL2; 98 FFTConvolver m_convolverR2; 99 100 AudioDelayDSPKernel m_delayLineL; 101 AudioDelayDSPKernel m_delayLineR; 102 103 AudioFloatArray m_tempL1; 104 AudioFloatArray m_tempR1; 105 AudioFloatArray m_tempL2; 106 AudioFloatArray m_tempR2; 107}; 108 109} // namespace blink 110 111#endif // HRTFPanner_h 112