features_extraction.h

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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_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:

  explicit FeaturesExtractor(const AvailableCpuFeatures& cpu_features);

  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_;

  int pitch_period_48kHz_;

};

}  // namespace rnn_vad

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_FEATURES_EXTRACTION_H_