---
title: Track reference type atom
framework: quicktime-file-format
role: symbol
role_heading: Atom
path: quicktime-file-format/track_reference_type_atom
---

# Track reference type atom

An atom that defines relationships with tracks of a specific type.

## Mentioned in

QuickTime File Format change log

## Overview

Overview Each track reference atom defines relationships with tracks of a specific type. The reference type implies a track type. The track reference types and their descriptions are as follows.  |   |   |   |   |   |   |   |   |   |   |   |  You can determine the number of track references stored in a track reference type atom by subtracting its header size from its overall size and then dividing by the size, in bytes, of a track ID.

## Topics

### Data fields

- [Size](quicktime-file-format/track_reference_type_atom/size.md)
- [Type](quicktime-file-format/track_reference_type_atom/type.md)
- [Track IDs](quicktime-file-format/track_reference_type_atom/track_ids.md)

## See Also

### Atoms for track references

- [Track reference atom ('tref')](quicktime-file-format/track_reference_atom.md)