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1 // Copyright 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 /** | |
6 * @fileoverview The manager of audio streams and interaction with the plugin. | |
7 */ | |
8 | |
9 cr.define('speech', function() { | |
10 'use strict'; | |
11 | |
12 /** | |
13 * The enum of the status of hotword audio recognition. | |
14 * | |
15 * @enum {number} | |
16 */ | |
17 var AudioState = { | |
18 UNINITIALIZED: 0, | |
19 READY: 1, | |
20 RECOGNIZING: 2 | |
21 }; | |
22 | |
23 /** | |
24 * @constructor | |
25 */ | |
26 function AudioManager(onReady, onRecognizing, onRecognized) { | |
27 this.state = AudioState.UNINITIALIZED; | |
28 if (!speech.isPluginAvailable) | |
29 return; | |
30 this.onReady_ = onReady; | |
31 this.onRecognizing_ = onRecognizing; | |
32 this.pluginManager_ = new speech.PluginManager( | |
33 this.onPluginReady_.bind(this), onRecognized); | |
34 this.audioContext_ = new window.webkitAudioContext(); | |
35 this.audioProc_ = null; | |
36 this.pluginManager_.scheduleInitialize( | |
37 this.audioContext_.sampleRate, | |
38 'chrome://app-list/okgoogle_hotword.config'); | |
39 }; | |
40 | |
41 /** | |
42 * Called when the plugin is ready. | |
43 * | |
44 * @private | |
45 */ | |
46 AudioManager.prototype.onPluginReady_ = function() { | |
47 this.state = AudioState.READY; | |
48 this.onReady_(); | |
49 }; | |
50 | |
51 /** | |
52 * Called when the audio data arrives. | |
53 * | |
54 * @param {Event} audio_event The audio event. | |
55 * @private | |
56 */ | |
57 AudioManager.prototype.onAudioProcess_ = function(audio_event) { | |
xiyuan
2013/10/29 18:10:07
audio_event -> audioEvent
Jun Mukai
2013/10/30 01:01:32
Done.
| |
58 var data = audio_event.inputBuffer.getChannelData(0); | |
59 var intData = new Int16Array(data.length); | |
60 for (var i = 0; i < data.length; ++i) | |
61 intData[i] = Math.round(data[i] * 32767); | |
62 this.pluginManager_.sendAudioData(intData.buffer); | |
63 }; | |
64 | |
65 /** | |
66 * Called when the audio stream is ready. | |
67 * | |
68 * @param {MediaStream} stream The media stream which is now available. | |
69 * @private | |
70 */ | |
71 AudioManager.prototype.onAudioReady_ = function(stream) { | |
72 var audioIn = this.audioContext_.createMediaStreamSource(stream); | |
73 this.audioProc_ = this.audioContext_.createScriptProcessor( | |
74 4096 /* buffer size */, 1 /* channels */, 1 /* channels */); | |
75 this.audioProc_.onaudioprocess = this.onAudioProcess_.bind(this); | |
76 | |
77 audioIn.connect(this.audioProc_); | |
78 this.audioProc_.connect(this.audioContext_.destination); | |
79 this.state = AudioState.RECOGNIZING; | |
80 this.onRecognizing_(); | |
81 }; | |
82 | |
83 /** | |
84 * Starts the audio recognition with the plugin. | |
85 */ | |
86 AudioManager.prototype.start = function() { | |
87 // Not yet initialized. | |
88 if (this.state != AudioState.READY) | |
89 return; | |
90 if (this.pluginManager_.state < speech.PluginState.READY) | |
91 return; | |
92 | |
93 if (this.pluginManager_.state == speech.PluginState.READY) | |
94 this.pluginManager_.startRecognizer(); | |
95 | |
96 if (this.audioProc_) { | |
97 this.audioProc_.connect(this.audioContext_.destination); | |
98 this.state = AudioState.RECOGNIZING; | |
99 this.onRecognizing_(); | |
100 return; | |
101 } | |
102 | |
103 navigator.webkitGetUserMedia( | |
104 {audio: true}, | |
105 this.onAudioReady_.bind(this), | |
106 function(msg) { console.error('Failed to getUserMedia: ' + msg); }); | |
107 }; | |
108 | |
109 /** | |
110 * Stops the audio recognition. | |
111 */ | |
112 AudioManager.prototype.stop = function() { | |
113 if (this.state <= AudioState.READY) | |
114 return; | |
115 this.audioProc_.disconnect(); | |
116 this.pluginManager_.stopRecognizer(); | |
117 this.state = AudioState.READY; | |
118 }; | |
119 | |
120 return { | |
121 AudioManager: AudioManager | |
122 }; | |
123 }); | |
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