OptionalenabledTells if a subtitle track is enabled or disabled.
If set to true, the track will be enabled by default.
OptionalforcedTells if a subtitle track is forced.
If set to true, it means that the player should automatically select and switch to this subtitle according to the selected audio language.
The id of the media track that is used to identify and set the track.
OptionalisIndicates whether the subtitle is fragmented.
The subtitle type, either "caption" or "subtitle" (default: "subtitle").
The text used to represent this track to the user (e.g. in the UI).
The language of the subtitle/caption track.
OptionalroleThe optional roles of the track.
OptionalurlThe URL to the associated file.
Definition of a subtitle/caption track.