/Source/WebCore/platform/audio/HRTFKernel.h
C Header | 97 lines | 42 code | 17 blank | 38 comment | 0 complexity | 680c772f2f3080271e23ac37a384b69b MD5 | raw file
Possible License(s): AGPL-1.0, BSD-3-Clause, LGPL-2.1, MPL-2.0-no-copyleft-exception
- /*
- * 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 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
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- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- #ifndef HRTFKernel_h
- #define HRTFKernel_h
- #include "FFTFrame.h"
- #include <memory>
- #include <wtf/PassRefPtr.h>
- #include <wtf/RefCounted.h>
- #include <wtf/RefPtr.h>
- #include <wtf/Vector.h>
- namespace WebCore {
- class AudioChannel;
-
- // 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 RefCounted<HRTFKernel> {
- public:
- // Note: this is destructive on the passed in AudioChannel.
- // The length of channel must be a power of two.
- static PassRefPtr<HRTFKernel> create(AudioChannel* channel, size_t fftSize, float sampleRate)
- {
- return adoptRef(new HRTFKernel(channel, fftSize, sampleRate));
- }
- static PassRefPtr<HRTFKernel> create(std::unique_ptr<FFTFrame> fftFrame, float frameDelay, float sampleRate)
- {
- return adoptRef(new HRTFKernel(std::move(fftFrame), frameDelay, sampleRate));
- }
- // Given two HRTFKernels, and an interpolation factor x: 0 -> 1, returns an interpolated HRTFKernel.
- static PassRefPtr<HRTFKernel> createInterpolatedKernel(HRTFKernel* kernel1, HRTFKernel* kernel2, float x);
-
- FFTFrame* fftFrame() { return m_fftFrame.get(); }
-
- size_t fftSize() const;
- float frameDelay() const { return m_frameDelay; }
- float sampleRate() const { return m_sampleRate; }
- double nyquist() const { return 0.5 * sampleRate(); }
- // Converts back into impulse-response form.
- std::unique_ptr<AudioChannel> createImpulseResponse();
- private:
- // Note: this is destructive on the passed in AudioChannel.
- HRTFKernel(AudioChannel*, size_t fftSize, float sampleRate);
-
- HRTFKernel(std::unique_ptr<FFTFrame> fftFrame, float frameDelay, float sampleRate)
- : m_fftFrame(std::move(fftFrame))
- , m_frameDelay(frameDelay)
- , m_sampleRate(sampleRate)
- {
- }
-
- std::unique_ptr<FFTFrame> m_fftFrame;
- float m_frameDelay;
- float m_sampleRate;
- };
- typedef Vector<RefPtr<HRTFKernel>> HRTFKernelList;
- } // namespace WebCore
- #endif // HRTFKernel_h