content/browser/speech/speech_recognizer_impl.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_IMPL_H_
   6 #define CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_IMPL_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "content/browser/speech/endpointer/endpointer.h"
  11 #include "content/browser/speech/speech_recognition_engine.h"
  12 #include "content/browser/speech/speech_recognizer.h"
  13 #include "content/public/common/speech_recognition_error.h"
  14 #include "content/public/common/speech_recognition_result.h"
  15 #include "media/audio/audio_input_controller.h"
  16 #include "media/audio/audio_logging.h"
  17 #include "net/url_request/url_request_context_getter.h"
  18
  19 namespace media {
  20 class AudioBus;
  21 class AudioManager;
  22 }
  23
  24 namespace content {
  25
  26 class SpeechRecognitionEventListener;
  27
  28 // Handles speech recognition for a session (identified by |session_id|), taking
  29 // care of audio capture, silence detection/endpointer and interaction with the
  30 // SpeechRecognitionEngine.
  31 class CONTENT_EXPORT SpeechRecognizerImpl
  32     : public SpeechRecognizer,
  33       public media::AudioInputController::EventHandler,
  34       public NON_EXPORTED_BASE(SpeechRecognitionEngineDelegate) {
  35  public:
  36   static const int kAudioSampleRate;
  37   static const media::ChannelLayout kChannelLayout;
  38   static const int kNumBitsPerAudioSample;
  39   static const int kNoSpeechTimeoutMs;
  40   static const int kEndpointerEstimationTimeMs;
  41
  42   static void SetAudioManagerForTesting(media::AudioManager* audio_manager);
  43
  44   SpeechRecognizerImpl(SpeechRecognitionEventListener* listener,
  45                        int session_id,
  46                        bool continuous,
  47                        bool provisional_results,
  48                        SpeechRecognitionEngine* engine);
  49
  50   virtual void StartRecognition(const std::string& device_id) OVERRIDE;
  51   virtual void AbortRecognition() OVERRIDE;
  52   virtual void StopAudioCapture() OVERRIDE;
  53   virtual bool IsActive() const OVERRIDE;
  54   virtual bool IsCapturingAudio() const OVERRIDE;
  55   const SpeechRecognitionEngine& recognition_engine() const;
  56
  57  private:
  58   friend class SpeechRecognizerTest;
  59
  60   enum FSMState {
  61     STATE_IDLE = 0,
  62     STATE_STARTING,
  63     STATE_ESTIMATING_ENVIRONMENT,
  64     STATE_WAITING_FOR_SPEECH,
  65     STATE_RECOGNIZING,
  66     STATE_WAITING_FINAL_RESULT,
  67     STATE_ENDED,
  68     STATE_MAX_VALUE = STATE_ENDED
  69   };
  70
  71   enum FSMEvent {
  72     EVENT_ABORT = 0,
  73     EVENT_START,
  74     EVENT_STOP_CAPTURE,
  75     EVENT_AUDIO_DATA,
  76     EVENT_ENGINE_RESULT,
  77     EVENT_ENGINE_ERROR,
  78     EVENT_AUDIO_ERROR,
  79     EVENT_MAX_VALUE = EVENT_AUDIO_ERROR
  80   };
  81
  82   struct FSMEventArgs {
  83     explicit FSMEventArgs(FSMEvent event_value);
  84     ~FSMEventArgs();
  85
  86     FSMEvent event;
  87     scoped_refptr<AudioChunk> audio_data;
  88     SpeechRecognitionResults engine_results;
  89     SpeechRecognitionError engine_error;
  90   };
  91
  92   virtual ~SpeechRecognizerImpl();
  93
  94   // Entry point for pushing any new external event into the recognizer FSM.
  95   void DispatchEvent(const FSMEventArgs& event_args);
  96
  97   // Defines the behavior of the recognizer FSM, selecting the appropriate
  98   // transition according to the current state and event.
  99   FSMState ExecuteTransitionAndGetNextState(const FSMEventArgs& args);
 100
 101   // Process a new audio chunk in the audio pipeline (endpointer, vumeter, etc).
 102   void ProcessAudioPipeline(const AudioChunk& raw_audio);
 103
 104   // The methods below handle transitions of the recognizer FSM.
 105   FSMState StartRecording(const FSMEventArgs& event_args);
 106   FSMState StartRecognitionEngine(const FSMEventArgs& event_args);
 107   FSMState WaitEnvironmentEstimationCompletion(const FSMEventArgs& event_args);
 108   FSMState DetectUserSpeechOrTimeout(const FSMEventArgs& event_args);
 109   FSMState StopCaptureAndWaitForResult(const FSMEventArgs& event_args);
 110   FSMState ProcessIntermediateResult(const FSMEventArgs& event_args);
 111   FSMState ProcessFinalResult(const FSMEventArgs& event_args);
 112   FSMState AbortSilently(const FSMEventArgs& event_args);
 113   FSMState AbortWithError(const FSMEventArgs& event_args);
 114   FSMState Abort(const SpeechRecognitionError& error);
 115   FSMState DetectEndOfSpeech(const FSMEventArgs& event_args);
 116   FSMState DoNothing(const FSMEventArgs& event_args) const;
 117   FSMState NotFeasible(const FSMEventArgs& event_args);
 118
 119   // Returns the time span of captured audio samples since the start of capture.
 120   int GetElapsedTimeMs() const;
 121
 122   // Calculates the input volume to be displayed in the UI, triggering the
 123   // OnAudioLevelsChange event accordingly.
 124   void UpdateSignalAndNoiseLevels(const float& rms, bool clip_detected);
 125
 126   void CloseAudioControllerAsynchronously();
 127
 128   // Callback called on IO thread by audio_controller->Close().
 129   void OnAudioClosed(media::AudioInputController*);
 130
 131   // AudioInputController::EventHandler methods.
 132   virtual void OnCreated(media::AudioInputController* controller) OVERRIDE {}
 133   virtual void OnRecording(media::AudioInputController* controller) OVERRIDE {}
 134   virtual void OnError(media::AudioInputController* controller,
 135       media::AudioInputController::ErrorCode error_code) OVERRIDE;
 136   virtual void OnData(media::AudioInputController* controller,
 137                       const media::AudioBus* data) OVERRIDE;
 138   virtual void OnLog(media::AudioInputController* controller,
 139                      const std::string& message) OVERRIDE {}
 140
 141   // SpeechRecognitionEngineDelegate methods.
 142   virtual void OnSpeechRecognitionEngineResults(
 143       const SpeechRecognitionResults& results) OVERRIDE;
 144   virtual void OnSpeechRecognitionEngineError(
 145       const SpeechRecognitionError& error) OVERRIDE;
 146
 147   static media::AudioManager* audio_manager_for_tests_;
 148
 149   scoped_ptr<SpeechRecognitionEngine> recognition_engine_;
 150   Endpointer endpointer_;
 151   scoped_refptr<media::AudioInputController> audio_controller_;
 152   scoped_ptr<media::AudioLog> audio_log_;
 153   int num_samples_recorded_;
 154   float audio_level_;
 155   bool is_dispatching_event_;
 156   bool provisional_results_;
 157   FSMState state_;
 158   std::string device_id_;
 159
 160   class OnDataConverter;
 161
 162   // Converts data between native input format and a WebSpeech specific
 163   // output format.
 164   scoped_ptr<SpeechRecognizerImpl::OnDataConverter> audio_converter_;
 165
 166   DISALLOW_COPY_AND_ASSIGN(SpeechRecognizerImpl);
 167 };
 168
 169 }  // namespace content
 170
 171 #endif  // CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_IMPL_H_