standalone_vad.h - mozsearch

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/*

 *  Copyright (c) 2012 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_AGC_STANDALONE_VAD_H_

#define MODULES_AUDIO_PROCESSING_AGC_STANDALONE_VAD_H_

#include <stddef.h>

#include <stdint.h>

#include "common_audio/vad/include/webrtc_vad.h"

#include "modules/audio_processing/vad/common.h"

namespace webrtc {

class StandaloneVad {

 public:

  static StandaloneVad* Create();

  ~StandaloneVad();

  // Outputs

  //   p: a buffer where probabilities are written to.

  //   length_p: number of elements of `p`.

//

  // return value:

  //    -1: if no audio is stored or VAD returns error.

  //     0: in success.

  // In case of error the content of `activity` is unchanged.

//

  // Note that due to a high false-positive (VAD decision is active while the

  // processed audio is just background noise) rate, stand-alone VAD is used as

  // a one-sided indicator. The activity probability is 0.5 if the frame is

  // classified as active, and the probability is 0.01 if the audio is

  // classified as passive. In this way, when probabilities are combined, the

  // effect of the stand-alone VAD is neutral if the input is classified as

  // active.

  int GetActivity(double* p, size_t length_p);

  // Expecting 10 ms of 16 kHz audio to be pushed in.

  int AddAudio(const int16_t* data, size_t length);

  // Set aggressiveness of VAD, 0 is the least aggressive and 3 is the most

  // aggressive mode. Returns -1 if the input is less than 0 or larger than 3,

  // otherwise 0 is returned.

  int set_mode(int mode);

  // Get the agressiveness of the current VAD.

  int mode() const { return mode_; }

 private:

  explicit StandaloneVad(VadInst* vad);

  static const size_t kMaxNum10msFrames = 3;

  // TODO(turajs): Is there a way to use scoped-pointer here?

  VadInst* vad_;

  int16_t buffer_[kMaxNum10msFrames * kLength10Ms];

  size_t index_;

  int mode_;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_AGC_STANDALONE_VAD_H_