The Track Reference Box provides a reference from the containing track to
another track in the presentation. These references are typed. A 'hint'
reference links from the containing hint track to the media data that it
hints. A content description reference 'cdsc' links a descriptive or
metadata track to the content which it describes.
Exactly one Track Reference Box can be contained within the Track Box.
If this box is not present, the track is not referencing any other track in
any way. The reference array is sized to fill the reference type box.
Fields inherited from class net.sourceforge.jaad.mp4.boxes.BoxImpl