---
title: QT atom container description key
framework: quicktime-file-format
role: article
role_heading: Article
path: quicktime-file-format/qt_atom_container_description_key
---

# QT atom container description key

Build QT atom container-based data structures.

## Overview

Overview Because QT atom container–based data structures are widely used in QuickTime, a description key is presented here. Its usage is illustrated in the following sections, Sprite media handler track properties QT atom container format and Sprite media handler sample QT atom container formats. [(QTAtomFormatName)] = atomType_1, id, index     data atomType_n, id, index     data The atoms may be required or optional:  // optional atom  // required atom <atomType> atomType The atom ID may be a number if it is required to be a constant, or it may be a list of valid atom IDs, indicating that multiple atoms of this type are allowed. 3               // one atom with id of 3 (1..3)          // three atoms with id's of 1, 2, and 3 (1, 5, 7)       // three atoms with id's of 1, 5, and 7 (anyUniqueIDs)  // multiple atoms each with a unique id The atom index may be a 1 if only one atom of this type is allowed, or it may be a range from 1 to some constant or variable. 1               // one atom of this type is allowed, index is always  1 (1..3)          // three atoms with indexes 1, 2, and 3 (1..numAtoms)   // numAtoms atoms with indexes of 1 to numAtoms The data may be leaf data in which its data type is listed inside of brackets [], or it may be a nested tree of atoms. [theDataType]   // leaf data of type theDataType childAtoms      // a nested tree of atoms Nested QTAtom format definitions [(AtomFormatName)] may appear in a definition.

## See Also

### Media data atom types

- [Sprite media](quicktime-file-format/sprite_media.md)
- [Sprite track properties](quicktime-file-format/sprite_track_properties.md)
- [Sprite track media format](quicktime-file-format/sprite_track_media_format.md)
- [Sprite media atom and data types](quicktime-file-format/sprite_media_atom_and_data_types.md)
- [Sprite button behaviors](quicktime-file-format/sprite_button_behaviors.md)
- [Sprite media handler track properties QT atom container format](quicktime-file-format/sprite_media_handler_track_properties_qt_atom_container_format.md)
- [Sprite media handler sample QT atom container formats](quicktime-file-format/sprite_media_handler_sample_qt_atom_container_formats.md)
- [Wired action grammar](quicktime-file-format/wired_action_grammar.md)
- [Tween media](quicktime-file-format/tween_media.md)
- [3D media](quicktime-file-format/3d_media.md)
- [VR media](quicktime-file-format/vr_media.md)
- [Node parent atom](quicktime-file-format/node_parent_atom.md)
- [Node location atom structure ('nloc')](quicktime-file-format/node_location_atom_structure.md)
- [Custom cursor atom](quicktime-file-format/custom_cursor_atom.md)
- [Node information atom container](quicktime-file-format/node_information_atom_container.md)