AudioContext.createJavaScriptNode() - Web APIs 编辑

Obsolete

This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

The AudioContext.createJavaScriptNode() method creates a JavaScriptNode which is used for directly manipulating audio data with JavaScript.

Important: This method is obsolete, and has been renamed to AudioContext.createScriptProcessor(). See also ScriptProcessorNode.

Syntax

var jsNode = audioCtx.createJavaScriptNode(bufferSize, numInputChannels, numOutputChannels);

Parameters

bufferSize

The buffer size must be in units of sample frames, i.e., one of: 256, 512, 1024, 2048, 4096, 8192, or 16384. It controls the frequency of callbacks asking for a buffer refill. Smaller sizes allow for lower latency and higher for better overall quality.

numInputChannels

The number of input channels in the audio stream.

numOutputChannels

The number of output channels in the audio stream.

Example

The following script illustrates the use of createJavaScriptNode():

var SineWave = function(context) {
  var that = this;
  this.x = 0; // Initial sample number
  this.context = context;
  this.node = context.createJavaScriptNode(1024, 1, 1);
  this.node.onaudioprocess = function(e) { that.process(e) };
}

SineWave.prototype.process = function(e) {
  var data = e.outputBuffer.getChannelData(0);
  for (var i = 0; i < data.length; ++i) {
    data[i] = Math.sin(this.x++);
  }
}

SineWave.prototype.play = function() {
  this.node.connect(this.context.destination);
}

SineWave.prototype.pause = function() {
  this.node.disconnect();
}

See also

• Generating Tones with the Web Audio API
• Exploring the HTML5 Web Audio: visualizing sound