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// Copyright 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.
/**
* @fileoverview The manager of audio streams and interaction with the plugin.
*/
cr.define('speech', function() {
'use strict';
/**
* The enum of the status of hotword audio recognition.
*
* @enum {number}
*/
var AudioState = {
UNINITIALIZED: 0,
READY: 1,
RECOGNIZING: 2
};
/**
* @constructor
*/
function AudioManager(onReady, onRecognizing, onRecognized) {
this.state = AudioState.UNINITIALIZED;
if (!speech.isPluginAvailable())
return;
this.onReady_ = onReady;
this.onRecognizing_ = onRecognizing;
this.pluginManager_ = new speech.PluginManager(
this.onPluginReady_.bind(this), onRecognized);
this.audioContext_ = new window.webkitAudioContext();
this.audioProc_ = null;
this.pluginManager_.scheduleInitialize(
this.audioContext_.sampleRate,
'chrome://app-list/okgoogle_hotword.config');
};
/**
* Called when the plugin is ready.
*
* @private
*/
AudioManager.prototype.onPluginReady_ = function() {
this.state = AudioState.READY;
this.onReady_();
};
/**
* Called when the audio data arrives.
*
* @param {Event} audioEvent The audio event.
* @private
*/
AudioManager.prototype.onAudioProcess_ = function(audioEvent) {
var data = audioEvent.inputBuffer.getChannelData(0);
var intData = new Int16Array(data.length);
for (var i = 0; i < data.length; ++i)
intData[i] = Math.round(data[i] * 32767);
this.pluginManager_.sendAudioData(intData.buffer);
};
/**
* Called when the audio stream is ready.
*
* @param {MediaStream} stream The media stream which is now available.
* @private
*/
AudioManager.prototype.onAudioReady_ = function(stream) {
var audioIn = this.audioContext_.createMediaStreamSource(stream);
this.audioProc_ = this.audioContext_.createScriptProcessor(
4096 /* buffer size */, 1 /* channels */, 1 /* channels */);
this.audioProc_.onaudioprocess = this.onAudioProcess_.bind(this);
audioIn.connect(this.audioProc_);
this.audioProc_.connect(this.audioContext_.destination);
this.state = AudioState.RECOGNIZING;
this.onRecognizing_();
};
/**
* Starts the audio recognition with the plugin.
*/
AudioManager.prototype.start = function() {
// Not yet initialized.
if (this.state != AudioState.READY)
return;
if (this.pluginManager_.state < speech.PluginState.READY)
return;
if (this.pluginManager_.state == speech.PluginState.READY)
this.pluginManager_.startRecognizer();
if (this.audioProc_) {
this.audioProc_.connect(this.audioContext_.destination);
this.state = AudioState.RECOGNIZING;
this.onRecognizing_();
return;
}
navigator.webkitGetUserMedia(
{audio: true},
this.onAudioReady_.bind(this),
function(msg) { console.error('Failed to getUserMedia: ' + msg); });
};
/**
* Stops the audio recognition.
*/
AudioManager.prototype.stop = function() {
if (this.state <= AudioState.READY)
return;
this.audioProc_.disconnect();
this.pluginManager_.stopRecognizer();
this.state = AudioState.READY;
};
return {
AudioManager: AudioManager
};
});
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