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/Source/WebCore/platform/audio/HRTFKernel.h

https://bitbucket.org/codefirex/external_webkit
C Header | 98 lines | 43 code | 17 blank | 38 comment | 0 complexity | 857991b24729ff82ffa96f1f34d8ba17 MD5 | raw file
Possible License(s): LGPL-2.1, LGPL-2.0, BSD-3-Clause
  1. /*
  2. * Copyright (C) 2010 Google Inc. All rights reserved.
  3. *
  4. * Redistribution and use in source and binary forms, with or without
  5. * modification, are permitted provided that the following conditions
  6. * are met:
  7. *
  8. * 1. Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. * 2. Redistributions in binary form must reproduce the above copyright
  11. * notice, this list of conditions and the following disclaimer in the
  12. * documentation and/or other materials provided with the distribution.
  13. * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14. * its contributors may be used to endorse or promote products derived
  15. * from this software without specific prior written permission.
  16. *
  17. * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18. * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19. * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20. * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21. * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22. * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24. * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25. * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26. * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27. */
  28. #ifndef HRTFKernel_h
  29. #define HRTFKernel_h
  30. #include "FFTFrame.h"
  31. #include <wtf/OwnPtr.h>
  32. #include <wtf/PassOwnPtr.h>
  33. #include <wtf/PassRefPtr.h>
  34. #include <wtf/RefCounted.h>
  35. #include <wtf/RefPtr.h>
  36. #include <wtf/Vector.h>
  37. namespace WebCore {
  38. class AudioChannel;
  39. // HRTF stands for Head-Related Transfer Function.
  40. // HRTFKernel is a frequency-domain representation of an impulse-response used as part of the spatialized panning system.
  41. // For a given azimuth / elevation angle there will be one HRTFKernel for the left ear transfer function, and one for the right ear.
  42. // The leading delay (average group delay) for each impulse response is extracted:
  43. // m_fftFrame is the frequency-domain representation of the impulse response with the delay removed
  44. // m_frameDelay is the leading delay of the original impulse response.
  45. class HRTFKernel : public RefCounted<HRTFKernel> {
  46. public:
  47. // Note: this is destructive on the passed in AudioChannel.
  48. // The length of channel must be a power of two.
  49. static PassRefPtr<HRTFKernel> create(AudioChannel* channel, size_t fftSize, float sampleRate, bool bassBoost)
  50. {
  51. return adoptRef(new HRTFKernel(channel, fftSize, sampleRate, bassBoost));
  52. }
  53. static PassRefPtr<HRTFKernel> create(PassOwnPtr<FFTFrame> fftFrame, float frameDelay, float sampleRate)
  54. {
  55. return adoptRef(new HRTFKernel(fftFrame, frameDelay, sampleRate));
  56. }
  57. // Given two HRTFKernels, and an interpolation factor x: 0 -> 1, returns an interpolated HRTFKernel.
  58. static PassRefPtr<HRTFKernel> createInterpolatedKernel(HRTFKernel* kernel1, HRTFKernel* kernel2, float x);
  59. FFTFrame* fftFrame() { return m_fftFrame.get(); }
  60. size_t fftSize() const { return m_fftFrame->fftSize(); }
  61. float frameDelay() const { return m_frameDelay; }
  62. float sampleRate() const { return m_sampleRate; }
  63. double nyquist() const { return 0.5 * sampleRate(); }
  64. // Converts back into impulse-response form.
  65. PassOwnPtr<AudioChannel> createImpulseResponse();
  66. private:
  67. // Note: this is destructive on the passed in AudioChannel.
  68. HRTFKernel(AudioChannel*, size_t fftSize, float sampleRate, bool bassBoost);
  69. HRTFKernel(PassOwnPtr<FFTFrame> fftFrame, float frameDelay, float sampleRate)
  70. : m_fftFrame(fftFrame)
  71. , m_frameDelay(frameDelay)
  72. , m_sampleRate(sampleRate)
  73. {
  74. }
  75. OwnPtr<FFTFrame> m_fftFrame;
  76. float m_frameDelay;
  77. float m_sampleRate;
  78. };
  79. typedef Vector<RefPtr<HRTFKernel> > HRTFKernelList;
  80. } // namespace WebCore
  81. #endif // HRTFKernel_h