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    AudioContext.createBufferSource

    « AudioContext

    The createBufferSource() method of the AudioContext Interface is used to create a new AudioBufferSourceNode, which can be used to play audio data contained within an AudioBuffer object, or returned from AudioContext.decodeAudioData.

    Syntax

     AudioBufferSourceNode           createBufferSource ();

    Example

    In this example, we create a two second buffer, fill it with white noise, and then play it via an AudioBufferSourceNode. The comments should clearly explain what is going on.

    Note: You can also run the code live, or view the source.

    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();
    }

    Parameters

    None.

    Returns

    An AudioBufferSourceNode.

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
    Basic support 10.0webkit 25.0 (25.0)  Not supported 15.0webkit 6.0webkit
    Feature Android Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Andriod
    Basic support ? 26.0 1.2 ? ? ? 33.0

    Specifications

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

    See also

    Document Tags and Contributors

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