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/*
* Copyright (C) 2010, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*/
#ifndef HRTFPanner_h
#define HRTFPanner_h
#include "platform/audio/AudioDelayDSPKernel.h"
#include "platform/audio/FFTConvolver.h"
#include "platform/audio/HRTFDatabaseLoader.h"
#include "platform/audio/Panner.h"
namespace blink {
class PLATFORM_EXPORT HRTFPanner final : public Panner {
public:
HRTFPanner(float sampleRate, HRTFDatabaseLoader*);
~HRTFPanner() override;
// Panner
void pan(double azimuth,
double elevation,
const AudioBus* inputBus,
AudioBus* outputBus,
size_t framesToProcess,
AudioBus::ChannelInterpretation) override;
void panWithSampleAccurateValues(double* azimuth,
double* elevation,
const AudioBus* inputBus,
AudioBus* outputBus,
size_t framesToProcess,
AudioBus::ChannelInterpretation) override;
void reset() override;
size_t fftSize() const { return fftSizeForSampleRate(m_sampleRate); }
static size_t fftSizeForSampleRate(float sampleRate);
float sampleRate() const { return m_sampleRate; }
double tailTime() const override;
double latencyTime() const override;
private:
// Given an azimuth angle in the range -180 -> +180, returns the corresponding
// azimuth index for the database, and azimuthBlend which is an interpolation
// value from 0 -> 1.
int calculateDesiredAzimuthIndexAndBlend(double azimuth,
double& azimuthBlend);
RefPtr<HRTFDatabaseLoader> m_databaseLoader;
float m_sampleRate;
// We maintain two sets of convolvers for smooth cross-faded interpolations
// when then azimuth and elevation are dynamically changing. When the
// azimuth and elevation are not changing, we simply process with one
// of the two sets. Initially we use CrossfadeSelection1 corresponding to
// m_convolverL1 and m_convolverR1. Whenever the azimuth or elevation
// changes, a crossfade is initiated to transition to the new position. So if
// we're currently processing with CrossfadeSelection1, then we transition to
// CrossfadeSelection2 (and vice versa). If we're in the middle of a
// transition, then we wait until it is complete before initiating a new
// transition.
// Selects either the convolver set (m_convolverL1, m_convolverR1) or
// (m_convolverL2, m_convolverR2).
enum CrossfadeSelection { CrossfadeSelection1, CrossfadeSelection2 };
CrossfadeSelection m_crossfadeSelection;
// azimuth/elevation for CrossfadeSelection1.
int m_azimuthIndex1;
double m_elevation1;
// azimuth/elevation for CrossfadeSelection2.
int m_azimuthIndex2;
double m_elevation2;
// A crossfade value 0 <= m_crossfadeX <= 1.
float m_crossfadeX;
// Per-sample-frame crossfade value increment.
float m_crossfadeIncr;
FFTConvolver m_convolverL1;
FFTConvolver m_convolverR1;
FFTConvolver m_convolverL2;
FFTConvolver m_convolverR2;
AudioDelayDSPKernel m_delayLineL;
AudioDelayDSPKernel m_delayLineR;
AudioFloatArray m_tempL1;
AudioFloatArray m_tempR1;
AudioFloatArray m_tempL2;
AudioFloatArray m_tempR2;
};
} // namespace blink
#endif // HRTFPanner_h
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