---
title: "Metadata item keys atom ('keys')"
framework: quicktime-file-format
role: symbol
role_heading: Atom
path: quicktime-file-format/metadata_item_keys_atom
---

# Metadata item keys atom ('keys')

An atom that holds a list of the metadata keys that may be present in the metadata atom.

## Overview

Overview The metadata item keys atom holds a list of the metadata keys that may be present in the metadata atom. This list is indexed starting with 1; 0 is a reserved index value. The metadata item keys atom is a full atom with an atom type of ‘keys’. Note that: Indexes into the metadata item keys atom are 1-based (1…entry_count). Zero (0) is reserved and never used as an index. The structure of key_value depends upon the key namespace. The following figure shows a typical metadata item keys atom.

The following figure shows an example of a metadata item keys atom consisting of three keys: two from one key namespace and a third from another key namespace.

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## Topics

### Data fields

- [Size](quicktime-file-format/metadata_item_keys_atom/size.md)
- [Type](quicktime-file-format/metadata_item_keys_atom/type.md)
- [Version](quicktime-file-format/metadata_item_keys_atom/version.md)
- [Flags](quicktime-file-format/metadata_item_keys_atom/flags.md)
- [Entry_count](quicktime-file-format/metadata_item_keys_atom/entry_count.md)
- [Key_size](quicktime-file-format/metadata_item_keys_atom/key_size.md)
- [Key_namespace](quicktime-file-format/metadata_item_keys_atom/key_namespace.md)
- [Key_value[Key_size-8]](quicktime-file-format/metadata_item_keys_atom/key_value_key_size-8.md)

## See Also

### Atoms

- [Country list atom ('ctry')](quicktime-file-format/country_list_atom.md)
- [Language list atom ('lang')](quicktime-file-format/language_list_atom.md)
- [Metadata item list atom ('ilst')](quicktime-file-format/metadata_item_list_atom.md)
- [Metadata item atom](quicktime-file-format/metadata_item_atom.md)
- [Value atom](quicktime-file-format/value_atom.md)
- [Item information atom ('itif')](quicktime-file-format/item_information_atom.md)
- [Name atom ('name')](quicktime-file-format/name_atom.md)
- [Data atom ('data')](quicktime-file-format/data_atom.md)