The Web Audio API's MediaStreamTrackAudioSourceNode() constructor creates and returns a new MediaStreamTrackAudioSourceNode object whose audio is taken from the MediaStreamTrack specified in the given options object.

Another way to create a MediaStreamTrackAudioSourceNode is to call the AudioContext.createMediaStreamTrackSource() method, specifying the MediaStreamTrack from which you want to obtain audio.

context

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

options

An object defining the properties you want the MediaStreamTrackAudioSourceNode to have:

mediaStreamTrack

The MediaStreamTrack from which to take audio data for this node's output.

A new MediaStreamTrackAudioSourceNode object representing the audio node whose media is obtained from the specified media track.

NotSupportedError DOMException

Thrown if the specified context is not an AudioContext.

InvalidStateError DOMException

Thrown if the specified MediaStreamTrack isn't an audio track (that is, its kind property isn't audio.

This example uses getUserMedia() to obtain access to the user's camera, then creates a new MediaStreamAudioSourceNode from the first audio track provided by the device.

const audioCtx = new AudioContext();

if (navigator.mediaDevices.getUserMedia) {
  navigator.mediaDevices
    .getUserMedia({
      audio: true,
      video: false,
    })
    .then((stream) => {
      const options = {
        mediaStreamTrack: stream.getAudioTracks()[0],
      };

      const source = new MediaStreamTrackAudioSourceNode(audioCtx, options);
      source.connect(audioCtx.destination);
    })
    .catch((err) => {
      console.error(`The following gUM error occurred: ${err}`);
    });
} else {
  console.log("new getUserMedia not supported on your browser!");
}