If the asset linked to an Upload entity is a video file, you have the option to include additional audio tracks and subtitle tracks to it.
"upload_track"
The type of track (audio or subtitles)
The human-readable name of the track
A valid BCP 47 specification compliant language code
Indicates if the track provides subtitles for the Deaf or Hard-of-hearing (SDH)
The status of the asset
When status is errored
, explains the reason for the error
The upload containing the track