| /* |
| * 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 "platform/audio/FFTFrame.h" |
| #include "wtf/OwnPtr.h" |
| #include "wtf/PassOwnPtr.h" |
| #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 PLATFORM_EXPORT 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(PassOwnPtr<FFTFrame> fftFrame, float frameDelay, float sampleRate) |
| { |
| return adoptRef(new HRTFKernel(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 { return m_fftFrame->fftSize(); } |
| 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. |
| PassOwnPtr<AudioChannel> createImpulseResponse(); |
| |
| private: |
| // Note: this is destructive on the passed in AudioChannel. |
| HRTFKernel(AudioChannel*, size_t fftSize, float sampleRate); |
| |
| HRTFKernel(PassOwnPtr<FFTFrame> fftFrame, float frameDelay, float sampleRate) |
| : m_fftFrame(fftFrame) |
| , m_frameDelay(frameDelay) |
| , m_sampleRate(sampleRate) |
| { |
| } |
| |
| OwnPtr<FFTFrame> m_fftFrame; |
| float m_frameDelay; |
| float m_sampleRate; |
| }; |
| |
| typedef Vector<RefPtr<HRTFKernel> > HRTFKernelList; |
| |
| } // namespace WebCore |
| |
| #endif // HRTFKernel_h |