how to extract subtitle stream from a video with javascript

I'm trying to display subtitles of a video, I have a video with an embedded subtitle stream in it,

it showing subtitle stream on ffprobe but not on javascript, tried with captureStream API which will return MediaStream object to see the available tracks but it's only returning audio/video tracks not subtitle tracks

guessing web standard doesn't have a spec to return all the tracks other than audio/video it will be helpful if you have a solution for this. but I appreciate your help. thanks.