DynamicsCompressorNode.release - Web APIs 编辑

The release property of the DynamicsCompressorNode interface Is a k-rate AudioParam representing the amount of time, in seconds, required to increase the gain by 10 dB. It defines how quick the signal is adapted when its volume is reduced.

The release property's default value is 0.25 and it can be set between 0 and 1.

Syntax

var audioCtx = new AudioContext();
var compressor = audioCtx.createDynamicsCompressor();
compressor.release.value = 0.25;

Value

An AudioParam.

Note: Though the AudioParam returned is read-only, the value it represents is not.

Example

The below code demonstrates a simple usage of createDynamicsCompressor() to add compression to an audio track. For a more complete example, have a look at our basic Compressor example (view the source code).

// Create a MediaElementAudioSourceNode
// Feed the HTMLMediaElement into it
var source = audioCtx.createMediaElementSource(myAudio);

// Create a compressor node
var compressor = audioCtx.createDynamicsCompressor();
compressor.threshold.setValueAtTime(-50, audioCtx.currentTime);
compressor.knee.setValueAtTime(40, audioCtx.currentTime);
compressor.ratio.setValueAtTime(12, audioCtx.currentTime);
compressor.attack.setValueAtTime(0, audioCtx.currentTime);
compressor.release.setValueAtTime(0.25, audioCtx.currentTime);

// connect the AudioBufferSourceNode to the destination
source.connect(audioCtx.destination);

button.onclick = function() {
  var active = button.getAttribute('data-active');
  if(active == 'false') {
    button.setAttribute('data-active', 'true');
    button.textContent = 'Remove compression';

    source.disconnect(audioCtx.destination);
    source.connect(compressor);
    compressor.connect(audioCtx.destination);
  } else if(active == 'true') {
    button.setAttribute('data-active', 'false');
    button.textContent = 'Add compression';

    source.disconnect(compressor);
    compressor.disconnect(audioCtx.destination);
    source.connect(audioCtx.destination);
  }
}

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using the Web Audio API