1 files changed, 110 insertions, 0 deletions
diff --git a/chromium/third_party/blink/renderer/platform/audio/hrtf_kernel.h b/chromium/third_party/blink/renderer/platform/audio/hrtf_kernel.h
new file mode 100644
index 00000000000..6758b9a15b0
--- /dev/null
+++ b/chromium/third_party/blink/renderer/platform/audio/hrtf_kernel.h
@@ -0,0 +1,110 @@
+/*
+ * 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_HRTF_KERNEL_H_
+#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_HRTF_KERNEL_H_
+
+#include <memory>
+#include <utility>
+
+#include "base/memory/ptr_util.h"
+#include "third_party/blink/renderer/platform/audio/fft_frame.h"
+#include "third_party/blink/renderer/platform/wtf/allocator.h"
+#include "third_party/blink/renderer/platform/wtf/noncopyable.h"
+#include "third_party/blink/renderer/platform/wtf/vector.h"
+
+namespace blink {
+
+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 {
+  USING_FAST_MALLOC(HRTFKernel);
+  WTF_MAKE_NONCOPYABLE(HRTFKernel);
+
+ public:
+  // Note: this is destructive on the passed in AudioChannel.
+  // The length of channel must be a power of two.
+  static std::unique_ptr<HRTFKernel> Create(AudioChannel* channel,
+                                            size_t fft_size,
+                                            float sample_rate) {
+    return base::WrapUnique(new HRTFKernel(channel, fft_size, sample_rate));
+  }
+
+  static std::unique_ptr<HRTFKernel> Create(std::unique_ptr<FFTFrame> fft_frame,
+                                            float frame_delay,
+                                            float sample_rate) {
+    return base::WrapUnique(
+        new HRTFKernel(std::move(fft_frame), frame_delay, sample_rate));
+  }
+
+  // Given two HRTFKernels, and an interpolation factor x: 0 -> 1, returns an
+  // interpolated HRTFKernel.
+  static std::unique_ptr<HRTFKernel>
+  CreateInterpolatedKernel(HRTFKernel* kernel1, HRTFKernel* kernel2, float x);
+
+  FFTFrame* FftFrame() { return fft_frame_.get(); }
+
+  size_t FftSize() const { return fft_frame_->FftSize(); }
+  float FrameDelay() const { return frame_delay_; }
+
+  float SampleRate() const { return sample_rate_; }
+  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 fft_size, float sample_rate);
+
+  HRTFKernel(std::unique_ptr<FFTFrame> fft_frame,
+             float frame_delay,
+             float sample_rate)
+      : fft_frame_(std::move(fft_frame)),
+        frame_delay_(frame_delay),
+        sample_rate_(sample_rate) {}
+
+  std::unique_ptr<FFTFrame> fft_frame_;
+  float frame_delay_;
+  float sample_rate_;
+};
+
+typedef Vector<std::unique_ptr<HRTFKernel>> HRTFKernelList;
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_HRTF_KERNEL_H_