65 lines
2.0 KiB
C++
65 lines
2.0 KiB
C++
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/*
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* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/audio_processing/ns/ns_fft.h"
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#include "common_audio/third_party/ooura/fft_size_256/fft4g.h"
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namespace webrtc {
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NrFft::NrFft() : bit_reversal_state_(kFftSize / 2), tables_(kFftSize / 2) {
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// Initialize WebRtc_rdt (setting (bit_reversal_state_[0] to 0 triggers
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// initialization)
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bit_reversal_state_[0] = 0.f;
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std::array<float, kFftSize> tmp_buffer;
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tmp_buffer.fill(0.f);
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WebRtc_rdft(kFftSize, 1, tmp_buffer.data(), bit_reversal_state_.data(),
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tables_.data());
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}
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void NrFft::Fft(rtc::ArrayView<float, kFftSize> time_data,
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rtc::ArrayView<float, kFftSize> real,
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rtc::ArrayView<float, kFftSize> imag) {
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WebRtc_rdft(kFftSize, 1, time_data.data(), bit_reversal_state_.data(),
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tables_.data());
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imag[0] = 0;
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real[0] = time_data[0];
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imag[kFftSizeBy2Plus1 - 1] = 0;
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real[kFftSizeBy2Plus1 - 1] = time_data[1];
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for (size_t i = 1; i < kFftSizeBy2Plus1 - 1; ++i) {
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real[i] = time_data[2 * i];
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imag[i] = time_data[2 * i + 1];
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}
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}
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void NrFft::Ifft(rtc::ArrayView<const float> real,
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rtc::ArrayView<const float> imag,
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rtc::ArrayView<float> time_data) {
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time_data[0] = real[0];
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time_data[1] = real[kFftSizeBy2Plus1 - 1];
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for (size_t i = 1; i < kFftSizeBy2Plus1 - 1; ++i) {
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time_data[2 * i] = real[i];
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time_data[2 * i + 1] = imag[i];
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}
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WebRtc_rdft(kFftSize, -1, time_data.data(), bit_reversal_state_.data(),
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tables_.data());
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// Scale the output
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constexpr float kScaling = 2.f / kFftSize;
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for (float& d : time_data) {
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d *= kScaling;
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}
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}
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} // namespace webrtc
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