Track references
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 | description | specification |
|---|---|---|
adda | Additional audio track | ISO |
adrc | DRC metadata track | ISO |
auxl | Auxiliary track reference | ISO |
avcp | AVC parameter set stream link | NALu Video |
cdsc | this track describes the referenced track. | ISO |
cdtg | this track describes the referenced tracks and track groups collectively | OMAF |
deps | track containing the depth view | NALu Video |
dpnd | this track has an MPEG-4 dependency on the referenced track | MP4v2 |
evcr | EVC slice base track | NALu Video |
font | this track uses fonts carried/defined in the referenced track | ISO |
hind | Hint dependency | ISO |
hint | links hint track to original media track | ISO |
ipir | this track contains IPI declarations for the referenced track | MP4v2 |
lyra | Audio layer track dependency | DTS |
mixn | used in indicating combinations that result into mixed network abstraction layer unit types in a coded picture of VVC | NALu Video |
mpod | this track is an OD track which uses the referenced track as an included elementary stream track | MP4v2 |
oref | track that contains an 'oref' sample group | NALu Video |
recr | resolved by extracting an indicated subset of the referenced VVC track to reconstruct a VVC bitstream | NALu Video |
sabt | HEVC Tile Track | NALu Video |
sbas | Scalable base | NALu Video |
scal | Scalable extraction | NALu Video |
shsc | reference to a shadow sync sample track | OMAF |
subp | the referenced VVC subpicture tracks or 'alte' track groups of VVC subpicture tracks are used to reconstruct a VVC bitstream | NALu Video |
subt | subtitle or timed text or overlay graphical information | ISO |
swfr | AVC Switch from | NALu Video |
swto | AVC Switch to | NALu Video |
sync | this track uses the referenced track as its synchronization source. | MP4v2 |
tbas | HEVC Tile track base | NALu Video |
thmb | Thumbnail track reference | ISO |
tmcd | Time code. Usually references a time code track. | Apple |
v3cs | V3C atlas track | V3C-SYS |
v3ct | V3C atlas tile track | V3C-SYS |
v3va | V3C attribute video track | V3C-SYS |
v3vg | V3C geometry video track | V3C-SYS |
v3vo | V3C occupancy video track | V3C-SYS |
vdep | Auxiliary video depth | ISO |
vplx | Auxiliary video parallax | ISO |
vref | reference to a track that contains a 'vopi' sample group for VVC video | NALu Video |
vreg | reference to a VVC operating point entity group | NALu Video |
vvcN | the referenced track is a non video coding layer track of VVC | NALu Video |
supm | The referenced tracks provide supplementary video to achieve picture-in-picture functionality | NALu Video |
QuickTime code-points
code | description | specification |
|---|---|---|
cdep | Structural Dependency | QT |
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 |