1 /*
2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef MODULES_AUDIO_PROCESSING_VAD_PITCH_BASED_VAD_H_
12 #define MODULES_AUDIO_PROCESSING_VAD_PITCH_BASED_VAD_H_
13 
14 #include <memory>
15 
16 #include "modules/audio_processing/vad/common.h"
17 #include "modules/audio_processing/vad/gmm.h"
18 
19 namespace webrtc {
20 
21 class VadCircularBuffer;
22 
23 // Computes the probability of the input audio frame to be active given
24 // the corresponding pitch-gain and lag of the frame.
25 class PitchBasedVad {
26  public:
27   PitchBasedVad();
28   ~PitchBasedVad();
29 
30   // Compute pitch-based voicing probability, given the features.
31   //   features: a structure containing features required for computing voicing
32   //             probabilities.
33   //
34   //   p_combined: an array which contains the combined activity probabilities
35   //               computed prior to the call of this function. The method,
36   //               then, computes the voicing probabilities and combine them
37   //               with the given values. The result are returned in |p|.
38   int VoicingProbability(const AudioFeatures& features, double* p_combined);
39 
40  private:
41   int UpdatePrior(double p);
42 
43   // TODO(turajs): maybe defining this at a higher level (maybe enum) so that
44   // all the code recognize it as "no-error."
45   static const int kNoError = 0;
46 
47   GmmParameters noise_gmm_;
48   GmmParameters voice_gmm_;
49 
50   double p_prior_;
51 
52   std::unique_ptr<VadCircularBuffer> circular_buffer_;
53 };
54 
55 }  // namespace webrtc
56 
57 #endif  // MODULES_AUDIO_PROCESSING_VAD_PITCH_BASED_VAD_H_
58