modules/audio_processing/vad/voice_activity_detector.h

/*
 *  Copyright (c) 2015 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_VAD_VOICE_ACTIVITY_DETECTOR_H_
#define MODULES_AUDIO_PROCESSING_VAD_VOICE_ACTIVITY_DETECTOR_H_

#include <memory>
#include <vector>

#include "common_audio/resampler/include/resampler.h"
#include "modules/audio_processing/vad/vad_audio_proc.h"
#include "modules/audio_processing/vad/common.h"
#include "modules/audio_processing/vad/pitch_based_vad.h"
#include "modules/audio_processing/vad/standalone_vad.h"

namespace webrtc {

// A Voice Activity Detector (VAD) that combines the voice probability from the
// StandaloneVad and PitchBasedVad to get a more robust estimation.
class VoiceActivityDetector {
 public:
  VoiceActivityDetector();
  ~VoiceActivityDetector();

  // Processes each audio chunk and estimates the voice probability. The maximum
  // supported sample rate is 32kHz.
  // TODO(aluebs): Change |length| to size_t.
  void ProcessChunk(const int16_t* audio, size_t length, int sample_rate_hz);

  // Returns a vector of voice probabilities for each chunk. It can be empty for
  // some chunks, but it catches up afterwards returning multiple values at
  // once.
  const std::vector<double>& chunkwise_voice_probabilities() const {
    return chunkwise_voice_probabilities_;
  }

  // Returns a vector of RMS values for each chunk. It has the same length as
  // chunkwise_voice_probabilities().
  const std::vector<double>& chunkwise_rms() const { return chunkwise_rms_; }

  // Returns the last voice probability, regardless of the internal
  // implementation, although it has a few chunks of delay.
  float last_voice_probability() const { return last_voice_probability_; }

 private:
  // TODO(aluebs): Change these to float.
  std::vector<double> chunkwise_voice_probabilities_;
  std::vector<double> chunkwise_rms_;

  float last_voice_probability_;

  Resampler resampler_;
  VadAudioProc audio_processing_;

  std::unique_ptr<StandaloneVad> standalone_vad_;
  PitchBasedVad pitch_based_vad_;

  int16_t resampled_[kLength10Ms];
  AudioFeatures features_;
};

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_VAD_VOICE_ACTIVITY_DETECTOR_H_