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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.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE 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 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 HRTFKernel_h
#define HRTFKernel_h
#include "nsAutoPtr.h"
#include "nsAutoRef.h"
#include "nsTArray.h"
#include "mozilla/FFTBlock.h"
#include "mozilla/MemoryReporting.h"
namespace WebCore {
using mozilla::FFTBlock;
// HRTF stands for Head-Related Transfer Function.
// HRTFKernel is a frequency-domain representation of an impulse-response used as part of the spatialized panning system.
// For a given azimuth / elevation angle there will be one HRTFKernel for the left ear transfer function, and one for the right ear.
// The leading delay (average group delay) for each impulse response is extracted:
// m_fftFrame is the frequency-domain representation of the impulse response with the delay removed
// m_frameDelay is the leading delay of the original impulse response.
class HRTFKernel {
public:
// Note: this is destructive on the passed in |impulseResponse|.
// The |length| of |impulseResponse| must be a power of two.
// The size of the DFT will be |2 * length|.
static nsReturnRef<HRTFKernel> create(float* impulseResponse, size_t length, float sampleRate);
static nsReturnRef<HRTFKernel> create(nsAutoPtr<FFTBlock> fftFrame, float frameDelay, float sampleRate);
// Given two HRTFKernels, and an interpolation factor x: 0 -> 1, returns an interpolated HRTFKernel.
static nsReturnRef<HRTFKernel> createInterpolatedKernel(HRTFKernel* kernel1, HRTFKernel* kernel2, float x);
FFTBlock* fftFrame() { return m_fftFrame.get(); }
size_t fftSize() const { return m_fftFrame->FFTSize(); }
float frameDelay() const { return m_frameDelay; }
float sampleRate() const { return m_sampleRate; }
double nyquist() const { return 0.5 * sampleRate(); }
size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
size_t amount = aMallocSizeOf(this);
amount += m_fftFrame->SizeOfIncludingThis(aMallocSizeOf);
return amount;
}
private:
HRTFKernel(const HRTFKernel& other) = delete;
void operator=(const HRTFKernel& other) = delete;
// Note: this is destructive on the passed in |impulseResponse|.
HRTFKernel(float* impulseResponse, size_t fftSize, float sampleRate);
HRTFKernel(nsAutoPtr<FFTBlock> fftFrame, float frameDelay, float sampleRate)
: m_fftFrame(fftFrame)
, m_frameDelay(frameDelay)
, m_sampleRate(sampleRate)
{
}
nsAutoPtr<FFTBlock> m_fftFrame;
float m_frameDelay;
float m_sampleRate;
};
typedef nsTArray<nsAutoRef<HRTFKernel> > HRTFKernelList;
} // namespace WebCore
template <>
class nsAutoRefTraits<WebCore::HRTFKernel> :
public nsPointerRefTraits<WebCore::HRTFKernel> {
public:
static void Release(WebCore::HRTFKernel* ptr) { delete(ptr); }
};
namespace WebCore {
inline nsReturnRef<HRTFKernel> HRTFKernel::create(float* impulseResponse, size_t length, float sampleRate)
{
return nsReturnRef<HRTFKernel>(new HRTFKernel(impulseResponse, length, sampleRate));
}
inline nsReturnRef<HRTFKernel> HRTFKernel::create(nsAutoPtr<FFTBlock> fftFrame, float frameDelay, float sampleRate)
{
return nsReturnRef<HRTFKernel>(new HRTFKernel(fftFrame, frameDelay, sampleRate));
}
} // namespace WebCore
#endif // HRTFKernel_h
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