This section documents the track-reference types, which link tracks with relationships between them. The link is typed with a code. These codes are documented here.

ISO Family code points (see below for QuickTime code points)

Code Abstract Defined in/by
avcp AVC parameter set stream link NALu Video
cdsc this track describes the referenced track. MPEG-4
dpnd this track has an MPEG-4 dependency on the referenced track MPEG-4
hind Hint dependency ISO
hint links hint track to original media track ISO
iloc Item data location (item reference) ISO
ipir this track contains IPI declarations for the referenced track MPEG-4
lyra Audio layer track dependency DTS
mpod this track is an OD track which uses the referenced track as an included elementary stream track MPEG-4
sbas Scalable base NALu Video
scal Scalable extraction NALu Video
swfr AVC Switch from NALu Video
swto AVC Switch to NALu Video
sync this track uses the referenced track as its synchronization source. MPEG-4
tmcd Time code. Usually references a time code track. Apple
vdep Auxiliary video depth ISO
vplx Auxiliary video parallax ISO

QuickTime code-points

Code Abstract Defined in/by
chap Chapter or scene list. Usually references a text track. QT
scpt Transcript. Usually references a text track. QT
ssrc Nonprimary source. Indicates that the referenced track should send its data to this track, rather than presenting it. QT
tmcd Time code. Usually references a time code track. QT