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Diffstat (limited to 'WebCore/platform/audio/HRTFKernel.h')
-rw-r--r-- | WebCore/platform/audio/HRTFKernel.h | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/WebCore/platform/audio/HRTFKernel.h b/WebCore/platform/audio/HRTFKernel.h new file mode 100644 index 0000000..572a085 --- /dev/null +++ b/WebCore/platform/audio/HRTFKernel.h @@ -0,0 +1,98 @@ +/* + * 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 "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 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, double sampleRate, bool bassBoost) + { + return adoptRef(new HRTFKernel(channel, fftSize, sampleRate, bassBoost)); + } + + static PassRefPtr<HRTFKernel> create(PassOwnPtr<FFTFrame> fftFrame, double frameDelay, double 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, double x); + + FFTFrame* fftFrame() { return m_fftFrame.get(); } + + size_t fftSize() const { return m_fftFrame->fftSize(); } + double frameDelay() const { return m_frameDelay; } + + double 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* channel, size_t fftSize, double sampleRate, bool bassBoost); + + HRTFKernel(PassOwnPtr<FFTFrame> fftFrame, double frameDelay, double sampleRate) + : m_fftFrame(fftFrame) + , m_frameDelay(frameDelay) + , m_sampleRate(sampleRate) + { + } + + OwnPtr<FFTFrame> m_fftFrame; + double m_frameDelay; + double m_sampleRate; +}; + +typedef Vector<RefPtr<HRTFKernel> > HRTFKernelList; + +} // namespace WebCore + +#endif // HRTFKernel_h |