Revision 930593 of ScriptProcessorNode

<p>{{APIRef("Web Audio API")}}</p>

<div class="note">
<p><strong>Note</strong>: As of the August 29 2014 Web Audio API spec publication, this feature has been marked as deprecated, and is soon to be replaced by <a href="/en-US/docs/Web/API/Web_Audio_API#Audio_Workers">Audio Workers</a>.</p>
</div>

<div>
<p>The <code>ScriptProcessorNode</code> interface allows the generation, processing, or analyzing of audio using JavaScript. It is an {{domxref("AudioNode")}} audio-processing module that is linked to two buffers, one containing the input audio data, one containing the processed output audio data. An event, implementing the {{domxref("AudioProcessingEvent")}} interface, is sent to the object each time the input buffer contains new data, and the event handler terminates when it has filled the output buffer with data.</p>
</div>

<p><img alt="The ScriptProcessorNode stores the input in a buffer, send the audioprocess event. The EventHandler takes the input buffer and fill the output buffer which is sent to the output by the ScriptProcessorNode." src="https://mdn.mozillademos.org/files/5157/WebAudioScriptProcessingNode.png" style="display:block; height:174px; margin:0px auto; width:306px" /></p>

<p>The size of the input and output buffer are defined at the creation time, when the {{domxref("AudioContext.createScriptProcessor()")}} method is called (both are defined by {{domxref("AudioContext.createScriptProcessor()")}}'s <code>bufferSize</code> parameter). The buffer size must be a power of 2 between <code>256</code> and <code>16384</code>, that is <code>256</code>, <code>512</code>, <code>1024</code>, <code>2048</code>, <code>4096</code>, <code>8192</code> or <code>16384</code>. Small numbers lower the <em>latency</em>, but large number may be necessary to avoid audio breakup and glitches.</p>

<p>If the buffer size is not defined, which is recommended, the browser will pick one that its heuristic deems appropriate.</p>

<table class="properties">
 <tbody>
  <tr>
   <th scope="row">Number of inputs</th>
   <td><code>1</code></td>
  </tr>
  <tr>
   <th scope="row">Number of outputs</th>
   <td><code>1</code></td>
  </tr>
  <tr>
   <th scope="row">Channel count mode</th>
   <td><code>"max"</code></td>
  </tr>
  <tr>
   <th scope="row">Channel count</th>
   <td><code>2</code> (not used in the default count mode)</td>
  </tr>
  <tr>
   <th scope="row">Channel interpretation</th>
   <td><code>"speakers"</code></td>
  </tr>
 </tbody>
</table>

<h2 id="Properties">Properties</h2>

<p><em>Inherits properties from its parent, </em><em>{{domxref("AudioNode")}}</em>.</p>

<dl>
 <dt>{{domxref("ScriptProcessorNode.bufferSize")}} {{readonlyInline}}</dt>
 <dd>Returns an integer representing both the input and output buffer size. Its value can be a power of 2 value in the range <code>256</code>–<code>16384</code>.</dd>
</dl>

<h3 id="Event_handlers">Event handlers</h3>

<dl>
 <dt>{{domxref("ScriptProcessorNode.onaudioprocess")}}</dt>
 <dd>Represents the {{domxref("EventHandler")}} to be called.</dd>
</dl>

<h2 id="Methods">Methods</h2>

<p><em>No specific methods; inherits methods from its parent, </em><em>{{domxref("AudioNode")}}</em>.</p>

<h2 id="Example">Example</h2>

<p>{{page("/en-US/docs/Web/API/AudioContext.createScriptProcessor","Example")}}</p>

<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-scriptprocessornode-interface---deprecated', 'ScriptProcessorNode')}}</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>14 {{property_prefix("webkit")}}</td>
   <td>{{CompatGeckoDesktop(25)}}</td>
   <td>{{CompatNo}}</td>
   <td>15&nbsp;{{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>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&nbsp;{{property_prefix("webkit")}}</td>
   <td>{{CompatGeckoMobile(25)}}</td>
   <td>1.2</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>6&nbsp;{{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>