Revision 666121 of AudioNode

<p>{{APIRef()}}</p>
<p>The <code>AudioNode</code> interface is a generic interface for representing an audio processing module like an audio source (e.g. an HTML {{HTMLElement("audio")}} or {{HTMLElement("video")}} element, an {{domxref("OscillatorNode")}}, etc.), the audio destination, intermediate processing module (e.g. a filter like {{domxref("BiquadFilterNode")}} or {{domxref("ConvolverNode")}}), or volume control (like {{domxref("GainNode")}}).</p>
<p><img alt="AudioNodes participating in an AudioContext create a audio routing graph." src="https://mdn.mozillademos.org/files/5081/WebAudioBasics.png" style="width: 355px; height: 260px; display: block; margin: 0px auto;" /></p>
<p>An <code>AudioNode</code> has inputs and outputs, each with a given amount of <em>channels</em>.<em> </em>An <code>AudioNode</code> with zero inputs and one or multiple outputs is called a <em>source node</em>. The exactly processing done varies from one <code>AudioNode</code> to another but, in general, a node reads its inputs, does some audio-related processing, and generates new values for its outputs, or simply lets the audio passes through (for example in the {{domxref("AnalyserNode")}}, where the result of the processing is accessed separatly).</p>
<p>Different nodes can be linked together to build a <em>processing graph</em>. Such a graph is contained in an {{domxref("AudioContext")}}. Each <code>AudioNode</code> participates in exactly one such context. In general, processing nodes inherit the properties and methods of <code>AudioNode</code>, but also define their own functionality on top. See the individual node pages for more details, as listed on the <a href="/en-US/docs/Web/API/Web_Audio_API">Web Audio API</a> homepage.</p>
<div class="note">
 <p><strong>Note</strong>: An <code>AudioNode</code> can be target of events, therefore it implements the {{domxref("EventTarget")}} interface.</p>
</div>
<h2 id="Properties" style="clear:both">Properties</h2>
<dl>
 <dt>
  {{domxref("AudioNode.context")}} {{readonlyInline}}</dt>
 <dd>
  Returns the associated {{domxref("AudioContext")}}, that is the object representing the processing graph the node is participating in.</dd>
</dl>
<dl>
 <dt>
  {{domxref("AudioNode.numberOfInputs")}} {{readonlyInline}}</dt>
 <dd>
  Returns the number of inputs feeding the node. Source nodes are defined as nodes having a <code>numberOfInputs</code> property with a value of <code>0</code>.</dd>
</dl>
<dl>
 <dt>
  {{domxref("AudioNode.numberOfOutputs")}} {{readonlyInline}}</dt>
 <dd>
  Returns the number of outputs coming out of the node. Destination nodes — like {{ domxref("AudioDestinationNode") }} — have a value of <code>0</code> for this attribute.</dd>
</dl>
<dl>
 <dt>
  {{domxref("AudioNode.channelCount")}}</dt>
 <dd>
  Represents an integer used to determine how many channels are used when <a href="/en-US/docs/Web/API/Web_Audio_API/Basic_concepts_behind_Web_Audio_API#Up-mixing_and_down-mixing">up-mixing and down-mixing</a> connections to any inputs to the node. Its usage and precise definition depend on the value of {{domxref("AudioNode.channelCountMode")}}.</dd>
</dl>
<dl>
 <dt>
  {{domxref("AudioNode.channelCountMode")}}</dt>
 <dd>
  Represents an enumerated value describing the way channels must be matched between the node's inputs and outputs.</dd>
 <dt>
  {{domxref("AudioNode.channelInterpretation")}}</dt>
 <dd>
  Represents an enumerated value describing the meaning of the channels. This interpretation will define how audio <a href="/en-US/docs/Web/API/Web_Audio_API/Basic_concepts_behind_Web_Audio_API#Up-mixing_and_down-mixing">up-mixing and down-mixing</a> will happen.<br />
  The possible values are <code>"speakers"</code> or <code>"discrete"</code>.</dd>
</dl>
<h2 id="Methods">Methods</h2>
<p><em>Also implements methods from the interface </em>{{domxref("EventTarget")}}.</p>
<dl>
 <dt>
  {{domxref("AudioNode.connect(AudioNode)")}}</dt>
 <dd>
  Allows us to connect one output of this node to one input of another node.</dd>
 <dt>
  {{domxref("AudioNode.connect(AudioParam)")}}</dt>
 <dd>
  Allows us to connect one output of this node to one input of an audio parameter.</dd>
 <dt>
  {{domxref("AudioNode.disconnect()")}}</dt>
 <dd>
  Allows us to disconnect the current node from another one it is already connected to.</dd>
</dl>
<h2 id="Example">Example</h2>
<p>This simple snippet of code shows the creation of some audio nodes, and how the <code>AudioNode</code> properties and methods can be used. You can find examples of such usage on any of the examples linked to on the <a href="/en-US/docs/Web/API/Web_Audio_API">Web Audio API</a> landing page (for example <a href="https://github.com/mdn/violent-theremin">Violent Theremin</a>.)<span class="p"> </span></p>
<pre class="brush: js;highlight[8,9,11,12,13,14]">
var AudioContext = window.AudioContext || window.webkitAudioContext;

var audioCtx = new AudioContext();

var oscillator = audioCtx.createOscillator();
var gainNode = audioCtx.createGain();

oscillator.connect(gainNode);
gainNode.connect(audioCtx.destination);

oscillator.context;
oscillator.numberOfInputs;
oscillator.numberOfOutputs;
oscillator.channelCount;</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', '#the-audionode-interface', 'AudioNode')}}</td>
   <td>{{Spec2('Web Audio API')}}</td>
   <td>&nbsp;</td>
  </tr>
 </tbody>
</table>
<h2 id="Browser_compatibility">Browser compatibility</h2>
<div>
 {{CompatibilityTable}}</div>
<div id="compat-desktop">
 <table class="compat-table">
  <tbody>
   <tr>
    <th>Feature</th>
    <th>Chrome</th>
    <th>Firefox (Gecko)</th>
    <th>Internet Explorer</th>
    <th>Opera</th>
    <th>Safari (WebKit)</th>
   </tr>
   <tr>
    <td>Basic support</td>
    <td>{{CompatChrome(10.0)}}{{property_prefix("webkit")}}</td>
    <td>{{CompatGeckoDesktop(25.0)}}</td>
    <td>{{CompatNo}}</td>
    <td>15.0{{property_prefix("webkit")}}<br />
     22 (unprefixed)</td>
    <td>{{CompatVersionUnknown}}</td>
   </tr>
   <tr>
    <td><code>channelCount</code> <code>channelCountMode</code></td>
    <td>{{CompatVersionUnknown}} {{property_prefix("webkit")}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
   </tr>
   <tr>
    <td><code>connect</code><code>(AudioParam)</code></td>
    <td>{{CompatVersionUnknown}} {{property_prefix("webkit")}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
   </tr>
  </tbody>
 </table>
</div>
<div id="compat-mobile">
 <table class="compat-table">
  <tbody>
   <tr>
    <th>Feature</th>
    <th>Android</th>
    <th>Firefox Mobile (Gecko)</th>
    <th>Firefox OS (Gecko)</th>
    <th>IE Phone</th>
    <th>Opera Mobile</th>
    <th>Safari Mobile</th>
   </tr>
   <tr>
    <td>Basic support</td>
    <td>{{CompatUnknown}}</td>
    <td>25.0</td>
    <td>1.2</td>
    <td>{{CompatUnknown}}</td>
    <td>{{CompatUnknown}}</td>
    <td>{{CompatUnknown}}</td>
   </tr>
   <tr>
    <td><code>channelCount</code><br />
     <code>channelCountMode</code></td>
    <td>{{CompatNo}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
   </tr>
   <tr>
    <td><code>connect</code><code>(AudioParam)</code></td>
    <td>{{CompatNo}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</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>