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---
title: AudioContext.createDelay()
slug: Web/API/BaseAudioContext/createDelay
translation_of: Web/API/BaseAudioContext/createDelay
original_slug: Web/API/AudioContext/createDelay
---
<p>{{ APIRef("Web Audio API") }}</p>
<div>
<p> <code>createDelay() 是 </code> {{ domxref("AudioContext") }} 的一个方法，作用是将输入音频信号延迟一定时间。（比如可以实现 对着话筒说句话，然后几秒后 这句话从音响里播放出来）</p>
<p> </p>
</div>
<h2 id="语法">语法</h2>
<pre class="brush: js">var audioCtx = new AudioContext();
var synthDelay = audioCtx.createDelay(<em>maxDelayTime</em>);</pre>
<h3 id="参数">参数</h3>
<dl>
<dt><em>maxDelayTime</em></dt>
<dd>设置最大允许延迟的时间，以“秒”为单位</dd>
</dl>
<h3 id="返回">返回</h3>
<p>A {{domxref("DelayNode")}}. The default {{domxref("DelayNode.delayTime")}} if no parameter is passed to <code>createDelay()</code> is 0 seconds.</p>
<p>以上是原文，大意是返回延时时间，没有设置时默认是0</p>
<p> </p>
<h2 id="示例">示例</h2>
<p>首先是中文版的简洁的示例，这个例子中 话筒里接收到的声音 会延迟3秒 从音响中播放</p>
<pre>window.AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext || window.msAudioContext;
<code>try {//音频相关api
var audioContext = new window.AudioContext();
</code> var synthDelay = <code>audioContext</code>.createDelay(5.0);
<code>} catch (e) {
alert("你浏览器不支持");
}
var error = function (error) {alert("有错误"); };
//以下是获取麦克风
if (navigator.getUserMedia) { //标准api
navigator.getUserMedia({ "audio": true },
function (stream) {
micto(stream); //具体工作
}, error);
}else if(navigator.webkitGetUserMedia) { //webkit api
navigator.webkitGetUserMedia({audio:true, video: false },
function (stream) {
micto(stream); //具体工作
}, error);
}else if (navigator.mozGetUserMedia) { //火狐 api
navigator.mozGetUserMedia({ "audio": true },
function (stream) {
micto(stream);//具体工作
}, error);
}else if (navigator.msGetUserMedia) { //ie api
navigator.msGetUserMedia({ "audio": true },
function (stream) {
micto(stream);//具体工作
}, error);
} else {
alert("您的浏览器版不支持这个api");
}
var micto = function(stream) {
synthDelay.delayTime.value = 3.0; //延迟3秒
var source = audioContext.createMediaStreamSource(stream);
source.connect(synthDelay);
synthDelay.connect(audioContext.destination);
}
</code></pre>
<p> </p>
<p> 以下是英文版示例</p>
<p>We have created a simple example that allows you to play three different samples on a constant loop — see <a href="http://chrisdavidmills.github.io/create-delay/">create-delay</a> (you can also <a href="https://github.com/chrisdavidmills/create-delay">view the source code</a>). If you just press the play buttons, the loops will start immediately; if you slide the sliders up to the right, then press the play buttons, a delay will be introduced, so the looping sounds don't start playing for a short amount of time.</p>
<pre class="brush: js;highlight[4,15,16,21,22]">var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioCtx = new AudioContext();
var synthDelay = audioCtx.createDelay(5.0);
...
var synthSource;
playSynth.onclick = function() {
synthSource = audioCtx.createBufferSource();
synthSource.buffer = buffers[2];
synthSource.loop = true;
synthSource.start();
synthSource.connect(synthDelay);
synthDelay.connect(destination);
this.setAttribute('disabled', 'disabled');
}
stopSynth.onclick = function() {
synthSource.disconnect(synthDelay);
synthDelay.disconnect(destination);
synthSource.stop();
playSynth.removeAttribute('disabled');
}
...
var delay1;
rangeSynth.oninput = function() {
delay1 = rangeSynth.value;
synthDelay.delayTime.value = delay1;
}
</pre>
<h2 id="Specifications">Specifications</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-AudioContext-createDelay-DelayNode-double-maxDelayTime', 'createDelay()')}}</td>
<td>{{Spec2('Web Audio API')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility">Browser compatibility</h2>
{{Compat("api.BaseAudioContext.createDelay")}}
<h2 id="See_also">See also</h2>
<ul>
<li><a href="/en-US/docs/Web_Audio_API/Using_Web_Audio_API">Using the Web Audio API</a></li>
</ul>
|
