Web/API/ScriptProcessorNode/audioprocess event

DeprecatedThis feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The audioprocess event of the ScriptProcessorNode interface is fired when an input buffer of a script processor is ready to be processed.

Bubbles	No
Cancelable	No
Default action	None
Interface	`AudioProcessingEvent`
Event handler property	`ScriptProcessorNode.onaudioprocess`

Examples

scriptNode.addEventListener('audioprocess', function(audioProcessingEvent) {
  // The input buffer is a song we loaded earlier
  var inputBuffer = audioProcessingEvent.inputBuffer;

  // The output buffer contains the samples that will be modified and played
  var outputBuffer = audioProcessingEvent.outputBuffer;

  // Loop through the output channels (in this case there is only one)
  for (var channel = 0; channel < outputBuffer.numberOfChannels; channel++) {
    var inputData = inputBuffer.getChannelData(channel);
    var outputData = outputBuffer.getChannelData(channel);

    // Loop through the 4096 samples
    for (var sample = 0; sample < inputBuffer.length; sample++) {
      // make output equal to the same as the input
      outputData[sample] = inputData[sample];

      // add noise to each output sample
      outputData[sample] += ((Math.random() * 2) - 1) * 0.2;         
    }
  }
})

You could also set up the event handler using the ScriptProcessorNode.onaudioprocess property:

scriptNode.onaudioprocess = function(audioProcessingEvent) {
  ...
}

Specifications

Specification	Status	Comment
Web Audio APIThe definition of 'AudioProcessingEvent' in that specification.	Working Draft

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`audioprocess` event Deprecated'	Chrome Full support 14 Prefixed' Full support 14 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 25	IE No support No	Opera Full support 22 Full support 22 Full support 15 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari Full support 6 Prefixed' Full support 6 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 25	Opera Android Full support 22 Full support 22 Full support 14 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari iOS Full support 6 Prefixed' Full support 6 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Samsung Internet Android Full support Yes

Legend

Full support: Full support
No support: No support
Deprecated. Not for use in new websites.': Deprecated. Not for use in new websites.
Requires a vendor prefix or different name for use.': Requires a vendor prefix or different name for use.

Web/API/ScriptProcessorNode/audioprocess event

Contents

Examples

Specifications

Browser compatibility

Legend

See also