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/*
* Copyright (c) 2018 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_AGC2_RNN_VAD_SPECTRAL_FEATURES_H_
#define MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_SPECTRAL_FEATURES_H_
#include <array>
#include <cstddef>
#include <memory>
#include <vector>
#include "api/array_view.h"
#include "modules/audio_processing/agc2/rnn_vad/common.h"
#include "modules/audio_processing/agc2/rnn_vad/ring_buffer.h"
#include "modules/audio_processing/agc2/rnn_vad/spectral_features_internal.h"
#include "modules/audio_processing/agc2/rnn_vad/symmetric_matrix_buffer.h"
#include "modules/audio_processing/utility/pffft_wrapper.h"
namespace webrtc {
namespace rnn_vad {
// Class to compute spectral features.
class SpectralFeaturesExtractor {
public:
SpectralFeaturesExtractor();
SpectralFeaturesExtractor(const SpectralFeaturesExtractor&) = delete;
SpectralFeaturesExtractor& operator=(const SpectralFeaturesExtractor&) =
delete;
~SpectralFeaturesExtractor();
// Resets the internal state of the feature extractor.
void Reset();
// Analyzes a pair of reference and lagged frames from the pitch buffer,
// detects silence and computes features. If silence is detected, the output
// is neither computed nor written.
bool CheckSilenceComputeFeatures(
rtc::ArrayView<const float, kFrameSize20ms24kHz> reference_frame,
rtc::ArrayView<const float, kFrameSize20ms24kHz> lagged_frame,
rtc::ArrayView<float, kNumBands - kNumLowerBands> higher_bands_cepstrum,
rtc::ArrayView<float, kNumLowerBands> average,
rtc::ArrayView<float, kNumLowerBands> first_derivative,
rtc::ArrayView<float, kNumLowerBands> second_derivative,
rtc::ArrayView<float, kNumLowerBands> bands_cross_corr,
float* variability);
private:
void ComputeAvgAndDerivatives(
rtc::ArrayView<float, kNumLowerBands> average,
rtc::ArrayView<float, kNumLowerBands> first_derivative,
rtc::ArrayView<float, kNumLowerBands> second_derivative) const;
void ComputeNormalizedCepstralCorrelation(
rtc::ArrayView<float, kNumLowerBands> bands_cross_corr);
float ComputeVariability() const;
const std::array<float, kFrameSize20ms24kHz / 2> half_window_;
Pffft fft_;
std::unique_ptr<Pffft::FloatBuffer> fft_buffer_;
std::unique_ptr<Pffft::FloatBuffer> reference_frame_fft_;
std::unique_ptr<Pffft::FloatBuffer> lagged_frame_fft_;
SpectralCorrelator spectral_correlator_;
std::array<float, kOpusBands24kHz> reference_frame_bands_energy_;
std::array<float, kOpusBands24kHz> lagged_frame_bands_energy_;
std::array<float, kOpusBands24kHz> bands_cross_corr_;
const std::array<float, kNumBands * kNumBands> dct_table_;
RingBuffer<float, kNumBands, kCepstralCoeffsHistorySize>
cepstral_coeffs_ring_buf_;
SymmetricMatrixBuffer<float, kCepstralCoeffsHistorySize> cepstral_diffs_buf_;
};
} // namespace rnn_vad
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_SPECTRAL_FEATURES_H_
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