AudioBuffer.length

The length property of the AudioBuffer interface returns an integer representing the length, in sample-frames, of the PCM data stored in the buffer.

Syntax

var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);
myArrayBuffer.length;

Value

A float.

Example

// 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;
    }
  }

  console.log(myArrayBuffer.length);
}

Specification

Specification Status Comment
Web Audio API
The definition of 'length' in that specification.
Working Draft  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 14 webkit (Yes) 23 No support 15 webkit
22 (unprefixed)
6 webkit
Feature Android Chrome Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support No support 28 webkit (Yes) 25 1.2 No support No support webkit

See also

Document Tags and Contributors

 Contributors to this page: erikadoyle, fscholz, chrisdavidmills
 Last updated by: erikadoyle,