The MediaStream.getTrackById() method returns a MediaStreamTrack object representing the track with the specified ID string. If there is no track with the specified ID, this method returns null.


var track = MediaStream.getTrackById(id);


A DOMString which identifies the track to be returned.

Return value

If a track is found for which matches the specified id string, that MediaStreamTrack object is returned. Otherwise, the returned value is null.


This example activates a commentary track on a video by ducking the audio level of the main audio track to 50%, then enabling the commentary track.

stream.getTrackById("primary-audio-track").applyConstraints({ volume: 0.5 });
stream.getTrackById("commentary-track").enabled = true;


Specification Status Comment
Media Capture and Streams
The definition of 'getTrackById()' in that specification.
Editor's Draft Initial specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support ? 49 (49) No support ? ?
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 49.0 (49) No support ? ?

See also


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