webrtc/modules/audio_processing/aec3/aec3_fft.h
Per Åhgren d20639f1f6 Correct the FFT windowing when computing the AEC NLP gain
This CL adds an nonwindowed spectrum of the linear filter error
to use in the NLP computation.

Bug: webrtc:8661
Change-Id: I45bc9bb3eb8eeac0c5d6adb414638eb12b635a27
Reviewed-on: https://webrtc-review.googlesource.com/38701
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21583}
2018-01-11 14:41:11 +00:00

65 lines
2 KiB
C++

/*
* 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 "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/aec3/fft_data.h"
#include "modules/audio_processing/utility/ooura_fft.h"
#include "rtc_base/constructormagic.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 };
Aec3Fft() = default;
// 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<float> x_old,
FftData* X) const;
private:
const OouraFft ooura_fft_;
RTC_DISALLOW_COPY_AND_ASSIGN(Aec3Fft);
};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_AEC3_AEC3_FFT_H_