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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_IMPL_H_
#define CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_IMPL_H_
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "content/browser/speech/endpointer/endpointer.h"
#include "content/browser/speech/speech_recognition_engine.h"
#include "content/browser/speech/speech_recognizer.h"
#include "content/public/common/speech_recognition_error.h"
#include "content/public/common/speech_recognition_result.h"
#include "media/audio/audio_input_controller.h"
#include "media/audio/audio_logging.h"
#include "net/url_request/url_request_context_getter.h"
namespace media {
class AudioBus;
class AudioManager;
}
namespace content {
class SpeechRecognitionEventListener;
// Handles speech recognition for a session (identified by |session_id|), taking
// care of audio capture, silence detection/endpointer and interaction with the
// SpeechRecognitionEngine.
class CONTENT_EXPORT SpeechRecognizerImpl
: public SpeechRecognizer,
public media::AudioInputController::EventHandler,
public NON_EXPORTED_BASE(SpeechRecognitionEngineDelegate) {
public:
static const int kAudioSampleRate;
static const media::ChannelLayout kChannelLayout;
static const int kNumBitsPerAudioSample;
static const int kNoSpeechTimeoutMs;
static const int kEndpointerEstimationTimeMs;
static void SetAudioManagerForTesting(media::AudioManager* audio_manager);
SpeechRecognizerImpl(SpeechRecognitionEventListener* listener,
int session_id,
bool continuous,
bool provisional_results,
SpeechRecognitionEngine* engine);
void StartRecognition(const std::string& device_id) override;
void AbortRecognition() override;
void StopAudioCapture() override;
bool IsActive() const override;
bool IsCapturingAudio() const override;
const SpeechRecognitionEngine& recognition_engine() const;
private:
friend class SpeechRecognizerTest;
enum FSMState {
STATE_IDLE = 0,
STATE_STARTING,
STATE_ESTIMATING_ENVIRONMENT,
STATE_WAITING_FOR_SPEECH,
STATE_RECOGNIZING,
STATE_WAITING_FINAL_RESULT,
STATE_ENDED,
STATE_MAX_VALUE = STATE_ENDED
};
enum FSMEvent {
EVENT_ABORT = 0,
EVENT_START,
EVENT_STOP_CAPTURE,
EVENT_AUDIO_DATA,
EVENT_ENGINE_RESULT,
EVENT_ENGINE_ERROR,
EVENT_AUDIO_ERROR,
EVENT_MAX_VALUE = EVENT_AUDIO_ERROR
};
struct FSMEventArgs {
explicit FSMEventArgs(FSMEvent event_value);
~FSMEventArgs();
FSMEvent event;
scoped_refptr<AudioChunk> audio_data;
SpeechRecognitionResults engine_results;
SpeechRecognitionError engine_error;
};
~SpeechRecognizerImpl() override;
// Entry point for pushing any new external event into the recognizer FSM.
void DispatchEvent(const FSMEventArgs& event_args);
// Defines the behavior of the recognizer FSM, selecting the appropriate
// transition according to the current state and event.
FSMState ExecuteTransitionAndGetNextState(const FSMEventArgs& args);
// Process a new audio chunk in the audio pipeline (endpointer, vumeter, etc).
void ProcessAudioPipeline(const AudioChunk& raw_audio);
// The methods below handle transitions of the recognizer FSM.
FSMState StartRecording(const FSMEventArgs& event_args);
FSMState StartRecognitionEngine(const FSMEventArgs& event_args);
FSMState WaitEnvironmentEstimationCompletion(const FSMEventArgs& event_args);
FSMState DetectUserSpeechOrTimeout(const FSMEventArgs& event_args);
FSMState StopCaptureAndWaitForResult(const FSMEventArgs& event_args);
FSMState ProcessIntermediateResult(const FSMEventArgs& event_args);
FSMState ProcessFinalResult(const FSMEventArgs& event_args);
FSMState AbortSilently(const FSMEventArgs& event_args);
FSMState AbortWithError(const FSMEventArgs& event_args);
FSMState Abort(const SpeechRecognitionError& error);
FSMState DetectEndOfSpeech(const FSMEventArgs& event_args);
FSMState DoNothing(const FSMEventArgs& event_args) const;
FSMState NotFeasible(const FSMEventArgs& event_args);
// Returns the time span of captured audio samples since the start of capture.
int GetElapsedTimeMs() const;
// Calculates the input volume to be displayed in the UI, triggering the
// OnAudioLevelsChange event accordingly.
void UpdateSignalAndNoiseLevels(const float& rms, bool clip_detected);
void CloseAudioControllerAsynchronously();
// Callback called on IO thread by audio_controller->Close().
void OnAudioClosed(media::AudioInputController*);
// AudioInputController::EventHandler methods.
void OnCreated(media::AudioInputController* controller) override {}
void OnRecording(media::AudioInputController* controller) override {}
void OnError(media::AudioInputController* controller,
media::AudioInputController::ErrorCode error_code) override;
void OnData(media::AudioInputController* controller,
const media::AudioBus* data) override;
void OnLog(media::AudioInputController* controller,
const std::string& message) override {}
// SpeechRecognitionEngineDelegate methods.
void OnSpeechRecognitionEngineResults(
const SpeechRecognitionResults& results) override;
void OnSpeechRecognitionEngineError(
const SpeechRecognitionError& error) override;
static media::AudioManager* audio_manager_for_tests_;
scoped_ptr<SpeechRecognitionEngine> recognition_engine_;
Endpointer endpointer_;
scoped_refptr<media::AudioInputController> audio_controller_;
scoped_ptr<media::AudioLog> audio_log_;
int num_samples_recorded_;
float audio_level_;
bool is_dispatching_event_;
bool provisional_results_;
FSMState state_;
std::string device_id_;
class OnDataConverter;
// Converts data between native input format and a WebSpeech specific
// output format.
scoped_ptr<SpeechRecognizerImpl::OnDataConverter> audio_converter_;
DISALLOW_COPY_AND_ASSIGN(SpeechRecognizerImpl);
};
} // namespace content
#endif // CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_IMPL_H_
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