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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_FEATURES_EXTRACTION_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_FEATURES_EXTRACTION_H_
+
+#include <vector>
+
+#include "api/array_view.h"
+#include "modules/audio_processing/agc2/biquad_filter.h"
+#include "modules/audio_processing/agc2/rnn_vad/common.h"
+#include "modules/audio_processing/agc2/rnn_vad/pitch_info.h"
+#include "modules/audio_processing/agc2/rnn_vad/pitch_search.h"
+#include "modules/audio_processing/agc2/rnn_vad/sequence_buffer.h"
+#include "modules/audio_processing/agc2/rnn_vad/spectral_features.h"
+
+namespace webrtc {
+namespace rnn_vad {
+
+// Feature extractor to feed the VAD RNN.
+class FeaturesExtractor {
+ public:
+  FeaturesExtractor();
+  FeaturesExtractor(const FeaturesExtractor&) = delete;
+  FeaturesExtractor& operator=(const FeaturesExtractor&) = delete;
+  ~FeaturesExtractor();
+  void Reset();
+  // Analyzes the samples, computes the feature vector and returns true if
+  // silence is detected (false if not). When silence is detected,
+  // |feature_vector| is partially written and therefore must not be used to
+  // feed the VAD RNN.
+  bool CheckSilenceComputeFeatures(
+      rtc::ArrayView<const float, kFrameSize10ms24kHz> samples,
+      rtc::ArrayView<float, kFeatureVectorSize> feature_vector);
+
+ private:
+  const bool use_high_pass_filter_;
+  // TODO(bugs.webrtc.org/7494): Remove HPF depending on how AGC2 is used in APM
+  // and on whether an HPF is already used as pre-processing step in APM.
+  BiQuadFilter hpf_;
+  SequenceBuffer<float, kBufSize24kHz, kFrameSize10ms24kHz, kFrameSize20ms24kHz>
+      pitch_buf_24kHz_;
+  rtc::ArrayView<const float, kBufSize24kHz> pitch_buf_24kHz_view_;
+  std::vector<float> lp_residual_;
+  rtc::ArrayView<float, kBufSize24kHz> lp_residual_view_;
+  PitchEstimator pitch_estimator_;
+  rtc::ArrayView<const float, kFrameSize20ms24kHz> reference_frame_view_;
+  SpectralFeaturesExtractor spectral_features_extractor_;
+  PitchInfo pitch_info_48kHz_;
+};
+
+}  // namespace rnn_vad
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_FEATURES_EXTRACTION_H_