GainNode

Verstärkung ist ein Wert ohne Einheit, der sich über die Zeit ändert. Er wird mit allen zeitlich korrespondierenden Samples aller Eingangskanäle multipliziert, um das Signal zu verändern.  Ändert sich der Wert, wird der neue Wert durch einen "de-zippering" Algorithmus angewendet, um unästhetisches Klick-Artifakte im Signal zu vermeiden.

Inherits properties from its parent, AudioNode.

GainNode.gain Read only

Ist ein a-rate AudioParam der das Ausmaß der Verstärkung angibt.

Keine spezifischen Methoden; erbt die Methoden der Elternklasse , AudioNode.

The following example shows basic usage of an AudioContext to create a GainNode, which is then used to mute and unmute the audio when a Mute button is clicked by changing the gain property value.

The below snippet wouldn't work as is — for a complete working example, check out our Voice-change-O-matic demo (view source.)

<div>
  <a class="mute">Mute button</a>
</div>

var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var gainNode = audioCtx.createGain();
var mute = document.querySelector('.mute');
var source;

if (navigator.mediaDevices.getUserMedia) {
 navigator.mediaDevices.getUserMedia (
   // constraints - only audio needed for this app
   {
     audio: true
   },

   // Success callback
   function(stream) {
     source = audioCtx.createMediaStreamSource(stream);

   },

   // Error callback
   function(err) {
     console.log('The following gUM error occured: ' + err);
   }
  );
} else {
   console.log('getUserMedia not supported on your browser!');
}

source.connect(gainNode);
gainNode.connect(audioCtx.destination);

  ...

mute.onclick = voiceMute;

function voiceMute() {
  if(mute.id == "") {
    gainNode.gain.setValueAtTime(0, audioCtx.currentTime);
    mute.id = "activated";
    mute.innerHTML = "Unmute";
  } else {
    gainNode.gain.setValueAtTime(1, audioCtx.currentTime);
    mute.id = "";
    mute.innerHTML = "Mute";
  }
}

• Die Web Audio API benutzen