The byteStreamTrackID read-only property of the TrackDefault interface returns the ID of the specific track that the SourceBuffer should apply to.
The kinds read-only property of the TrackDefault interface returns default kinds for an associated SourceBuffer to use when an initialization segment does not contain label information for a new track.
The label read-only property of the TrackDefault interface returns the default label for an associated SourceBuffer to use when an initialization segment does not contain label information for a new track.
The language read-only property of the TrackDefault interface returns a default language for an associated SourceBuffer to use when an initialization segment does not contain language information for a new track.
The TrackDefault() constructor of the TrackDefault interface constructs and returns a new TrackDefault object.
The type read-only property of the TrackDefault interface returns the type of track that this SourceBuffer's media segment data relates to (i.e. audio, video, or text track.)