---
title: AnalyserNode
slug: Web/API/AnalyserNode
translation_of: Web/API/AnalyserNode
---
<p>{{APIRef("Web Audio API")}}</p>

<p>La interfaz <strong><code>AnalyserNode</code></strong><strong> </strong>representa un nodo habilitado para proveer frecuencia en tiempo real y analisis de tiempo-dominio. Es un {{domxref("AudioNode")}} que pasa el flujo de audio sin modificación desde el origen de entrada a la salida, pero, te permite obtener los datos generados, procesarlos, y crear visualizaciones de audio.</p>

<p>Un <code>AnalyzerNode</code> tiene exactamente una entrada y una salida. El nodo trabaja incluso si la salida no se encuentra conectada.</p>

<p><img alt="Without modifying the audio stream, the node allows to get the frequency and time-domain data associated to it, using a FFT." src="https://mdn.mozillademos.org/files/9707/WebAudioFFT.png" style="height: 174px; width: 661px;"></p>

<table class="properties">
 <tbody>
  <tr>
   <th scope="row"><dfn>Numero de entradas</dfn></th>
   <td><code>1</code></td>
  </tr>
  <tr>
   <th scope="row"><dfn>Numero de salidas</dfn></th>
   <td><code>1</code> (puede estar desconectada)</td>
  </tr>
  <tr>
   <th scope="row"><dfn>Modo de conteo de canal</dfn></th>
   <td><code>"explicit"</code></td>
  </tr>
  <tr>
   <th scope="row"><dfn>Conteo de cana</dfn></th>
   <td><code>1</code></td>
  </tr>
  <tr>
   <th scope="row"><dfn>Interpretación de canal</dfn></th>
   <td><code>"speakers"</code></td>
  </tr>
 </tbody>
</table>

<h2 id="Herencia">Herencia</h2>

<p>Esta interfaz hereda de las siguientes interfaces padre:</p>

<p>{{InheritanceDiagram}}</p>

<h2 id="Propiedades">Propiedades</h2>

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

<dl>
 <dt>{{domxref("AnalyserNode.fftSize")}}</dt>
 <dd>Is an unsigned long value representing the size of the FFT (<a href="http://en.wikipedia.org/wiki/Fast_Fourier_transform" title="/en-US/docs/">Fast Fourier Transform</a>) to be used to determine the frequency domain.</dd>
 <dt>{{domxref("AnalyserNode.frequencyBinCount")}} {{readonlyInline}}</dt>
 <dd>Is an unsigned long value half that of the FFT size. This generally equates to the number of data values you will have to play with for the visualization.</dd>
 <dt>{{domxref("AnalyserNode.minDecibels")}}</dt>
 <dd>Is a double value representing the minimum power value in the scaling range for the FFT analysis data, for conversion to unsigned byte values — basically, this specifies the minimum value for the range of results when using <code>getByteFrequencyData()</code>.</dd>
 <dt>{{domxref("AnalyserNode.maxDecibels")}}</dt>
 <dd>Is a double value representing the maximum power value in the scaling range for the FFT analysis data, for conversion to unsigned byte values — basically, this specifies the maximum value for the range of results when using <code>getByteFrequencyData()</code>.</dd>
 <dt>{{domxref("AnalyserNode.smoothingTimeConstant")}}</dt>
 <dd>Is a double value representing the averaging constant with the last analysis frame — basically, it makes the transition between values over time smoother.</dd>
</dl>

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

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

<dl>
 <dt>{{domxref("AnalyserNode.getFloatFrequencyData()")}}</dt>
 <dd>Copies the current frequency data into a {{domxref("Float32Array")}} array passed into it.</dd>
</dl>

<dl>
 <dt>{{domxref("AnalyserNode.getByteFrequencyData()")}}</dt>
 <dd>Copies the current frequency data into a {{domxref("Uint8Array")}} (unsigned byte array) passed into it.</dd>
</dl>

<dl>
 <dt>{{domxref("AnalyserNode.getFloatTimeDomainData()")}}</dt>
 <dd>Copies the current waveform, or time-domain, data into a {{domxref("Float32Array")}} array passed into it.</dd>
 <dt>{{domxref("AnalyserNode.getByteTimeDomainData()")}}</dt>
 <dd>Copies the current waveform, or time-domain, data into a {{domxref("Uint8Array")}} (unsigned byte array) passed into it.</dd>
</dl>

<h2 id="Examples">Examples</h2>

<div class="note">
<p><strong>Note</strong>: See the guide <a href="/en-US/docs/Web/API/Web_Audio_API/Visualizations_with_Web_Audio_API">Visualizations with Web Audio API</a> for more information on creating audio visualizations.</p>
</div>

<h3 id="Basic_usage">Basic usage</h3>

<p>The following example shows basic usage of an {{domxref("AudioContext")}} to create an <code>AnalyserNode</code>, then {{domxref("window.requestAnimationFrame()","requestAnimationFrame")}} and {{htmlelement("canvas")}} to collect time domain data repeatedly and draw an "oscilloscope style" output of the current audio input. For more complete applied examples/information, check out our <a href="http://mdn.github.io/voice-change-o-matic/">Voice-change-O-matic</a> demo (see <a href="https://github.com/mdn/voice-change-o-matic/blob/gh-pages/scripts/app.js#L128-L205">app.js lines 128–205</a> for relevant code).</p>

<pre class="brush: js">var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var analyser = audioCtx.createAnalyser();

  ...

analyser.fftSize = 2048;
var bufferLength = analyser.frequencyBinCount;
var dataArray = new Uint8Array(bufferLength);
analyser.getByteTimeDomainData(dataArray);

// draw an oscilloscope of the current audio source

function draw() {

      drawVisual = requestAnimationFrame(draw);

      analyser.getByteTimeDomainData(dataArray);

      canvasCtx.fillStyle = 'rgb(200, 200, 200)';
      canvasCtx.fillRect(0, 0, WIDTH, HEIGHT);

      canvasCtx.lineWidth = 2;
      canvasCtx.strokeStyle = 'rgb(0, 0, 0)';

      canvasCtx.beginPath();

      var sliceWidth = WIDTH * 1.0 / bufferLength;
      var x = 0;

      for(var i = 0; i &lt; bufferLength; i++) {

        var v = dataArray[i] / 128.0;
        var y = v * HEIGHT/2;

        if(i === 0) {
          canvasCtx.moveTo(x, y);
        } else {
          canvasCtx.lineTo(x, y);
        }

        x += sliceWidth;
      }

      canvasCtx.lineTo(canvas.width, canvas.height/2);
      canvasCtx.stroke();
    };

    draw();</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-analysernode-interface', 'AnalyserNode')}}</td>
   <td>{{Spec2('Web Audio API')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

{{Compat("api.AnalyserNode")}}

<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>