1 files changed, 75 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/aec3_fft.h b/third_party/libwebrtc/modules/audio_processing/aec3/aec3_fft.h
new file mode 100644
index 0000000000..c68de53963
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/aec3/aec3_fft.h
@@ -0,0 +1,75 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AEC3_AEC3_FFT_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_AEC3_FFT_H_
+
+#include <array>
+
+#include "api/array_view.h"
+#include "common_audio/third_party/ooura/fft_size_128/ooura_fft.h"
+#include "modules/audio_processing/aec3/aec3_common.h"
+#include "modules/audio_processing/aec3/fft_data.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+// Wrapper class that provides 128 point real valued FFT functionality with the
+// FftData type.
+class Aec3Fft {
+ public:
+  enum class Window { kRectangular, kHanning, kSqrtHanning };
+
+  Aec3Fft();
+
+  Aec3Fft(const Aec3Fft&) = delete;
+  Aec3Fft& operator=(const Aec3Fft&) = delete;
+
+  // Computes the FFT. Note that both the input and output are modified.
+  void Fft(std::array<float, kFftLength>* x, FftData* X) const {
+    RTC_DCHECK(x);
+    RTC_DCHECK(X);
+    ooura_fft_.Fft(x->data());
+    X->CopyFromPackedArray(*x);
+  }
+  // Computes the inverse Fft.
+  void Ifft(const FftData& X, std::array<float, kFftLength>* x) const {
+    RTC_DCHECK(x);
+    X.CopyToPackedArray(x);
+    ooura_fft_.InverseFft(x->data());
+  }
+
+  // Windows the input using a Hanning window, and then adds padding of
+  // kFftLengthBy2 initial zeros before computing the Fft.
+  void ZeroPaddedFft(rtc::ArrayView<const float> x,
+                     Window window,
+                     FftData* X) const;
+
+  // Concatenates the kFftLengthBy2 values long x and x_old before computing the
+  // Fft. After that, x is copied to x_old.
+  void PaddedFft(rtc::ArrayView<const float> x,
+                 rtc::ArrayView<const float> x_old,
+                 FftData* X) const {
+    PaddedFft(x, x_old, Window::kRectangular, X);
+  }
+
+  // Padded Fft using a time-domain window.
+  void PaddedFft(rtc::ArrayView<const float> x,
+                 rtc::ArrayView<const float> x_old,
+                 Window window,
+                 FftData* X) const;
+
+ private:
+  const OouraFft ooura_fft_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AEC3_AEC3_FFT_H_