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/*
* 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(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(ArrayView<const float> x,
ArrayView<const float> x_old,
FftData* X) const {
PaddedFft(x, x_old, Window::kRectangular, X);
}
// Padded Fft using a time-domain window.
void PaddedFft(ArrayView<const float> x,
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_
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