blob: 054584f83b2d23e20266eb5049e3ccdae7d375b2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
---
title: AudioBuffer.length
slug: Web/API/AudioBuffer/length
translation_of: Web/API/AudioBuffer/length
---
<p>{{ APIRef("Web Audio API") }}</p>
<div>
<p>The <code>length</code> property of the {{ domxref("AudioBuffer") }} interface returns an integer representing the length, in sample-frames, of the PCM data stored in the buffer.</p>
<p>{{ domxref("AudioBuffer") }} 的length属性接口返回整数，该整数代表采样帧中，存贮在缓冲区中的PCM数据的长度</p>
</div>
<h2 id="语法">语法</h2>
<pre class="brush: js;highlight[22]">var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);
myArrayBuffer.length;</pre>
<h3 id="值">值</h3>
<p>浮点数</p>
<h2 id="例子">例子</h2>
<pre class="brush: js;highlight[22]">// Stereo
var channels = 2;
// Create an empty two second stereo buffer at the
// sample rate of the AudioContext
var frameCount = audioCtx.sampleRate * 2.0;
var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);
button.onclick = function() {
// Fill the buffer with white noise;
// just random values between -1.0 and 1.0
for (var channel = 0; channel < channels; channel++) {
// This gives us the actual ArrayBuffer that contains the data
var nowBuffering = myArrayBuffer.getChannelData(channel);
for (var i = 0; i < frameCount; i++) {
// Math.random() is in [0; 1.0]
// audio needs to be in [-1.0; 1.0]
nowBuffering[i] = Math.random() * 2 - 1;
}
}
console.log(myArrayBuffer.length);
}</pre>
<h2 id="规范">规范</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>{{SpecName('Web Audio API', '#widl-AudioBuffer-length', 'length')}}</td>
<td>{{Spec2('Web Audio API')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<div>{{CompatibilityTable}}</div>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Edge</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari (WebKit)</th>
</tr>
<tr>
<td>Basic support</td>
<td>14 {{property_prefix("webkit")}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>23</td>
<td>{{CompatNo}}</td>
<td>15 {{property_prefix("webkit")}}<br>
22 (unprefixed)</td>
<td>6 {{property_prefix("webkit")}}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome</th>
<th>Edge</th>
<th>Firefox Mobile (Gecko)</th>
<th>Firefox OS</th>
<th>IE Phone</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatNo}}</td>
<td>28 {{property_prefix("webkit")}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>25</td>
<td>1.2</td>
<td>{{CompatNo}}</td>
<td>{{CompatNo}}</td>
<td>6 {{property_prefix("webkit")}}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="See_also">See also</h2>
<ul>
<li><a href="/en-US/docs/Web/API/Web_Audio_API/Using_Web_Audio_API">Using the Web Audio API</a></li>
</ul>
|
