Web/API/AudioContext/createMediaStreamTrackSource

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The createMediaStreamTrackSource() method of the AudioContext interface creates and returns a MediaStreamTrackAudioSourceNode which represents an audio source whose data comes from the specified MediaStreamTrack.

This differs from createMediaStreamSource(), which creates a MediaStreamAudioSourceNode whose audio comes from the audio track in a specified MediaStream whose id is first, lexicographically (alphabetically).

Syntax

var audioCtx = new AudioContext();
var track = audioCtx.createMediaStreamTrackSource(track);

Parameters

track: The MediaStreamTrack to use as the source of all audio data for the new node.

Return value

A MediaStreamTrackAudioSourceNode object which acts as a source for audio data found in the specified audio track.

Example

In this example, getUserMedia() is used to request access to the user's microphone. Once that access is attained, an audio context is established and a MediaStreamTrackAudioSourceNode is created using createMediaStreamTrackSource(), taking its audio from the first audio track in the stream returned by getUserMedia().

Then a BiquadFilterNode is created using createBiquadFilter(), and it's configured as desired to perform a lowshelf filter on the audio coming from the source. The output from the microphone is then routed into the new biquad filter, and the filter's output is in turn routed to the audio context's destination.

navigator.mediaDevices.getUserMedia ({audio: true, video: false})
.then(function(stream) {
  audio.srcObject = stream;
  audio.onloadedmetadata = function(e) {
    audio.play();
    audio.muted = true;
  };

  let audioCtx = new AudioContext();
  let source = audioCtx.createMediaStreamSource(stream);

  let biquadFilter = audioCtx.createBiquadFilter();
  biquadFilter.type = "lowshelf";
  biquadFilter.frequency.value = 3000;
  biquadFilter.gain.value = 20;

  source.connect(biquadFilter);
  biquadFilter.connect(audioCtx.destination);
})
.catch(function(err) {
  // Handle getUserMedia() error
});

Specifications

Specification	Status	Comment
Web Audio APIThe definition of 'createMediaStreamTrackSource()' in that specification.	Working Draft

Browser compatibility

Update compatibility data on GitHub

	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
`createMediaStreamTrackSource`	Chrome No support No	Edge No support No	Firefox Full support 68 Notes' Full support 68 Notes' Notes' Firefox 68 implements the updated standard's definition of the "first" audio track; now the first track is the one whose ID comes first lexicographically.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 68 Notes' Full support 68 Notes' Notes' Firefox 68 implements the updated standard's definition of the "first" audio track; now the first track is the one whose ID comes first lexicographically.	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

Full support: Full support
No support: No support
See implementation notes.': See implementation notes.