---
title: Metadata header atom
framework: quicktime-file-format
role: symbol
role_heading: Data field
path: quicktime-file-format/metadata_atom/metadata_header_atom
---

# Metadata header atom

An atom that holds the integer value for the next unique item identifier to assign.

## Overview

Overview For more information, see Metadata header atom ('mhdr').

## See Also

### Data fields

- [Size](quicktime-file-format/metadata_atom/size.md)
- [Type](quicktime-file-format/metadata_atom/type.md)
- [Metadata handler atom](quicktime-file-format/metadata_atom/metadata_handler_atom.md)
- [Metadata item keys atom](quicktime-file-format/metadata_atom/metadata_item_keys_atom.md)
- [Metadata item list atom](quicktime-file-format/metadata_atom/metadata_item_list_atom.md)
- [Country list atom](quicktime-file-format/metadata_atom/country_list_atom.md)
- [Language list atom](quicktime-file-format/metadata_atom/language_list_atom.md)