The Web Audio API's MediaStreamAudioSourceNode() constructor creates and returns a new MediaStreamAudioSourceNode object which uses the first audio track of a given MediaStream as its source.

Note: Another way to create a MediaStreamAudioSourceNode is to call theAudioContext.createMediaStreamSource() method, specifying the stream from which you want to obtain audio.


audioSourceNode = new MediaStreamAudioSourceNode(context, options);


An AudioContext representing the audio context you want the node to be associated with.

A MediaStreamAudioSourceOptions object defining the properties you want the MediaStreamAudioSourceNode to have:

A required property which specifies the MediaStream from which to obtain audio for the node.

Return value

A new MediaStreamAudioSourceNode object representing the audio node whose media is obtained from the specified source stream.


The specified MediaStream doesn't have any audio tracks.


This example uses getUserMedia() to obtain access to the user's camera, then creates a new MediaStreamAudioSourceNode from its MediaStream.

// define variables
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();

// getUserMedia block - grab stream
// put it into a MediaStreamAudioSourceNode
if (navigator.mediaDevices.getUserMedia) {
   navigator.mediaDevices.getUserMedia (
      // constraints: audio and video for this app
         audio: true,
         video: false
      }).then(function(stream) {
        var options = {
          mediaStream : stream

        var source = new MediaStreamAudioSourceNode(audioCtx, options);
      }).catch(function(err) {
       console.log('The following gUM error occurred: ' + err);
} else {
  console.log('new getUserMedia not supported on your browser!');


Specification Status Comment
Web Audio API
The definition of 'MediaStreamAudioSourceNode()' in that specification.
Working Draft

Browser compatibility

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