ScriptProcessorNode

弃用
This 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.

ScriptProcessorNode interface allows the generation, processing, or analyzing of audio using JavaScript.

注意 : As of the August 29 2014 Web Audio API spec publication, this feature has been marked as deprecated, and was replaced by AudioWorklet (见 AudioWorkletNode ).

ScriptProcessorNode interface is an AudioNode audio-processing module that is linked to two buffers, one containing the input audio data, one containing the processed output audio data. An event, implementing the AudioProcessingEvent interface, is sent to the object each time the input buffer contains new data, and the event handler terminates when it has filled the output buffer with data.

The ScriptProcessorNode stores the input in a buffer, send the audioprocess event. The EventHandler takes the input buffer and fill the output buffer which is sent to the output by the ScriptProcessorNode.

The size of the input and output buffer are defined at the creation time, when the AudioContext.createScriptProcessor() method is called (both are defined by AudioContext.createScriptProcessor() 's bufferSize parameter). The buffer size must be a power of 2 between 256 and 16384 , that is 256 , 512 , 1024 , 2048 , 4096 , 8192 or 16384 . Small numbers lower the latency , but large number may be necessary to avoid audio breakup and glitches.

If the buffer size is not defined, which is recommended, the browser will pick one that its heuristic deems appropriate.

Number of inputs 1
Number of outputs 1
Channel count mode "max"
Channel count 2 (not used in the default count mode)
Channel interpretation "speakers"

特性

Inherits properties from its parent, AudioNode .

ScriptProcessorNode.bufferSize 只读
Returns an integer representing both the input and output buffer size. Its value can be a power of 2 value in the range 256 16384 .

方法

No specific methods; inherits methods from its parent, AudioNode .

Events

监听这些事件使用 addEventListener() 或通过把事件监听器赋值给 on eventname property of this interface:

audioprocess
Fired when an input buffer of a ScriptProcessorNode is ready to be processed.
Also available via the onaudioprocess event handler property.

范例

The following example shows basic usage of a ScriptProcessorNode to take a track loaded via AudioContext.decodeAudioData() , process it, adding a bit of white noise to each audio sample of the input track (buffer) and play it through the AudioDestinationNode . For each channel and each sample frame, the scriptNode.onaudioprocess function takes the associated audioProcessingEvent and uses it to loop through each channel of the input buffer, and each sample in each channel, and add a small amount of white noise, before setting that result to be the output sample in each case.

注意 : For a full working example, see our script-processor-node github repo (also view the source code .)

var myScript = document.querySelector('script');
var myPre = document.querySelector('pre');
var playButton = document.querySelector('button');
// Create AudioContext and buffer source
var audioCtx = new AudioContext();
source = audioCtx.createBufferSource();
// Create a ScriptProcessorNode with a bufferSize of 4096 and a single input and output channel
var scriptNode = audioCtx.createScriptProcessor(4096, 1, 1);
console.log(scriptNode.bufferSize);
// load in an audio track via XHR and decodeAudioData
function getData() {
  request = new XMLHttpRequest();
  request.open('GET', 'viper.ogg', true);
  request.responseType = 'arraybuffer';
  request.onload = function() {
    var audioData = request.response;
    audioCtx.decodeAudioData(audioData, function(buffer) {
    myBuffer = buffer;
    source.buffer = myBuffer;
  },
    function(e){"Error with decoding audio data" + e.err});
  }
  request.send();
}
// Give the node a function to process audio events
scriptNode.onaudioprocess = function(audioProcessingEvent) {
  // The input buffer is the 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;
    }
  }
}
getData();
// wire up play button
playButton.onclick = function() {
  source.connect(scriptNode);
  scriptNode.connect(audioCtx.destination);
  source.start();
}
// When the buffer source stops playing, disconnect everything
source.onended = function() {
  source.disconnect(scriptNode);
  scriptNode.disconnect(audioCtx.destination);
}
					

规范

规范 状态 Comment
Web 音频 API
The definition of 'ScriptProcessorNode' in that specification.
工作草案

浏览器兼容性

更新 GitHub 上的兼容性数据
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
ScriptProcessorNode
弃用
Chrome 14
Prefixed
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge ≤18 Firefox 25 IE 不支持 No Opera 22
22
15
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android Yes Chrome Android Yes Firefox Android 25 Opera Android 22
22
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari iOS 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Yes
audioprocess event
弃用
Chrome 14
Prefixed
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 25 IE 不支持 No Opera 22
22
15
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android Yes Chrome Android Yes Firefox Android 25 Opera Android 22
22
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari iOS 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Yes
bufferSize
弃用
Chrome 14
Prefixed
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 25 IE 不支持 No Opera 22
22
15
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android Yes Chrome Android Yes Firefox Android 25 Opera Android 22
22
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari iOS 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Yes
onaudioprocess
弃用
Chrome 14
Prefixed
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 25 IE 不支持 No Opera 22
22
15
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android Yes Chrome Android Yes Firefox Android 25 Opera Android 22
22
14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari iOS 6
Prefixed
6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Yes

图例

完整支持
完整支持
不支持
不支持
弃用。不要用于新网站。
弃用。不要用于新网站。
要求使用供应商前缀或不同名称。
要求使用供应商前缀或不同名称。

另请参阅