A media timeline track MUST carry a 'type' identifier in the Catalog with a value of "mediatimeline". A media timeline track MUST carry a 'depends' attribute which contains an array of all track names to which the media timeline track applies. The mime-type of a media timeline track MUST be specified as "application/json".
§7.2
Media Timeline Catalog requirements
This is one section of MOQT Streaming Format, rendered per-section for quick reference and citation. The authoritative text is draft-ietf-moq-msf-00 at the IETF.