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---
title: AudioBuffer.getChannelData()
slug: Web/API/AudioBuffer/getChannelData
translation_of: Web/API/AudioBuffer/getChannelData
---
<p>{{ APIRef("Web Audio API") }}</p>
<p> {{ domxref("AudioBuffer") }} 接口的getChannelData()方法返回一{{domxref("Float32Array")}} ，其中包含与通道关联的PCM数据，通道参数定义(0表示第一个通道)。</p>
<h2 id="语法">语法</h2>
<pre class="brush: js;highlight[22]">var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);
var nowBuffering = myArrayBuffer.getChannelData(channel);</pre>
<h3 id="参数">参数</h3>
<dl>
<dt>channel</dt>
<dd>channel属性是要获取特定通道数据的索引。0代表第一个通道。 如果索引值大于或等于{{domxref("AudioBuffer.numberOfChannels")}}, 会抛出一个索引大小异常（<code>INDEX_SIZE_ERR</code> ）的错误。</dd>
</dl>
<h3 id="返回值">返回值</h3>
<p> {{domxref("Float32Array")}}.</p>
<dl>
</dl>
<h2 id="例子">例子</h2>
<p>在下例中，我们创建一个2秒钟的缓冲区，用白噪声填充它，然后通过{{domxref("AudioBufferSourceNode") }}来播放它. 评论应该会清楚的解释发生的事情。 你也可以<a href="https://mdn.github.io/webaudio-examples/audio-buffer/">实时运行代码</a>，或者<a href="https://github.com/mdn/webaudio-examples">查看源代码</a>。</p>
<pre class="brush: js;highlight[21]">var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var button = document.querySelector('button');
var pre = document.querySelector('pre');
var myScript = document.querySelector('script');
pre.innerHTML = myScript.innerHTML;
// 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;
}
}
// Get an AudioBufferSourceNode.
// This is the AudioNode to use when we want to play an AudioBuffer
var source = audioCtx.createBufferSource();
// set the buffer in the AudioBufferSourceNode
source.buffer = myArrayBuffer;
// connect the AudioBufferSourceNode to the
// destination so we can hear the sound
source.connect(audioCtx.destination);
// start the source playing
source.start();
}</pre>
<h2 id="Specification">Specification</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', '#dom-audiobuffer-getchanneldata', 'getChannelData')}}</td>
<td>{{Spec2('Web Audio API')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility">Browser compatibility</h2>
<div>
<p>{{Compat("api.AudioBuffer.getChannelData")}}</p>
</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>
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