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Diffstat (limited to 'content/browser/speech/speech_recognizer.h')
| -rw-r--r-- | content/browser/speech/speech_recognizer.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/content/browser/speech/speech_recognizer.h b/content/browser/speech/speech_recognizer.h new file mode 100644 index 0000000..a54a59d --- /dev/null +++ b/content/browser/speech/speech_recognizer.h @@ -0,0 +1,151 @@ +// Copyright (c) 2010 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_H_ +#define CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_ + +#include <list> +#include <string> +#include <utility> + +#include "base/ref_counted.h" +#include "base/scoped_ptr.h" +#include "content/browser/speech/audio_encoder.h" +#include "content/browser/speech/endpointer/endpointer.h" +#include "content/browser/speech/speech_recognition_request.h" +#include "media/audio/audio_input_controller.h" + +namespace speech_input { + +// Records audio, sends recorded audio to server and translates server response +// to recognition result. +class SpeechRecognizer + : public base::RefCountedThreadSafe<SpeechRecognizer>, + public media::AudioInputController::EventHandler, + public SpeechRecognitionRequestDelegate { + public: + enum ErrorCode { + RECOGNIZER_NO_ERROR, + RECOGNIZER_ERROR_CAPTURE, + RECOGNIZER_ERROR_NO_SPEECH, + RECOGNIZER_ERROR_NO_RESULTS, + }; + + // Implemented by the caller to receive recognition events. + class Delegate { + public: + virtual void SetRecognitionResult( + int caller_id, + bool error, + const SpeechInputResultArray& result) = 0; + + // Invoked when audio recording stops, either due to the end pointer + // detecting silence in user input or if |StopRecording| was called. The + // delegate has to wait until |DidCompleteRecognition| is invoked before + // destroying the |SpeechRecognizer| object. + virtual void DidCompleteRecording(int caller_id) = 0; + + // This is guaranteed to be the last method invoked in the recognition + // sequence and the |SpeechRecognizer| object can be freed up if necessary. + virtual void DidCompleteRecognition(int caller_id) = 0; + + // Invoked if there was an error while recording or recognizing audio. The + // session has already been cancelled when this call is made and the DidXxxx + // callbacks will not be issued. It is safe to destroy/release the + // |SpeechRecognizer| object while processing this call. + virtual void OnRecognizerError(int caller_id, + SpeechRecognizer::ErrorCode error) = 0; + + // At the start of recognition, a short amount of audio is recorded to + // estimate the environment/background noise and this callback is issued + // after that is complete. Typically the delegate brings up any speech + // recognition UI once this callback is received. + virtual void DidCompleteEnvironmentEstimation(int caller_id) = 0; + + // Informs of a change in the captured audio level, useful if displaying + // a microphone volume indicator while recording. + // The value of |volume| is in the [0.0, 1.0] range. + virtual void SetInputVolume(int caller_id, float volume) = 0; + + protected: + virtual ~Delegate() {} + }; + + SpeechRecognizer(Delegate* delegate, + int caller_id, + const std::string& language, + const std::string& grammar, + const std::string& hardware_info, + const std::string& origin_url); + ~SpeechRecognizer(); + + // Starts audio recording and does recognition after recording ends. The same + // SpeechRecognizer instance can be used multiple times for speech recognition + // though each recognition request can be made only after the previous one + // completes (i.e. after receiving Delegate::DidCompleteRecognition). + bool StartRecording(); + + // Stops recording audio and starts recognition. + void StopRecording(); + + // Stops recording audio and cancels recognition. Any audio recorded so far + // gets discarded. + void CancelRecognition(); + + // AudioInputController::EventHandler methods. + virtual void OnCreated(media::AudioInputController* controller) { } + virtual void OnRecording(media::AudioInputController* controller) { } + virtual void OnError(media::AudioInputController* controller, int error_code); + virtual void OnData(media::AudioInputController* controller, + const uint8* data, + uint32 size); + + // SpeechRecognitionRequest::Delegate methods. + virtual void SetRecognitionResult(bool error, + const SpeechInputResultArray& result); + + static const int kAudioSampleRate; + static const int kAudioPacketIntervalMs; // Duration of each audio packet. + static const int kNumAudioChannels; + static const int kNumBitsPerAudioSample; + static const int kNoSpeechTimeoutSec; + static const int kEndpointerEstimationTimeMs; + + private: + void ReleaseAudioBuffers(); + void InformErrorAndCancelRecognition(ErrorCode error); + void SendRecordedAudioToServer(); + + void HandleOnError(int error_code); // Handles OnError in the IO thread. + + // Handles OnData in the IO thread. Takes ownership of |data|. + void HandleOnData(std::string* data); + + Delegate* delegate_; + int caller_id_; + std::string language_; + std::string grammar_; + std::string hardware_info_; + std::string origin_url_; + + scoped_ptr<SpeechRecognitionRequest> request_; + scoped_refptr<media::AudioInputController> audio_controller_; + AudioEncoder::Codec codec_; + scoped_ptr<AudioEncoder> encoder_; + Endpointer endpointer_; + int num_samples_recorded_; + float audio_level_; + + DISALLOW_COPY_AND_ASSIGN(SpeechRecognizer); +}; + +// This typedef is to workaround the issue with certain versions of +// Visual Studio where it gets confused between multiple Delegate +// classes and gives a C2500 error. (I saw this error on the try bots - +// the workaround was not needed for my machine). +typedef SpeechRecognizer::Delegate SpeechRecognizerDelegate; + +} // namespace speech_input + +#endif // CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_ |