---
title: "Base media information header atom ('gmhd')"
framework: quicktime-file-format
role: symbol
role_heading: Atom
path: quicktime-file-format/base_media_information_header_atom
---

# Base media information header atom ('gmhd')

An atom that indicates that this media information atom pertains to a base media.

## Overview

Overview The layout of a base media information header atom is as follows.  |   |   |   |   |  ‡ denotes required atom.

## Topics

### Data fields

- [Size](quicktime-file-format/base_media_information_header_atom/size.md)
- [Type](quicktime-file-format/base_media_information_header_atom/type.md)
- [Base media info atom](quicktime-file-format/base_media_information_header_atom/base_media_info_atom.md)
- [Text media information atom](quicktime-file-format/base_media_information_header_atom/text_media_information_atom.md)

## See Also

### Describing media

- [Media atom ('mdia')](quicktime-file-format/media_atom.md)
- [Media header atom ('mdhd')](quicktime-file-format/media_header_atom.md)
- [Extended language tag atom ('elng')](quicktime-file-format/extended_language_tag_atom.md)
- [Handler reference atom ('hdlr')](quicktime-file-format/handler_reference_atom.md)
- [Media information atoms](quicktime-file-format/media_information_atoms.md)
- [Video media information atom ('minf')](quicktime-file-format/video_media_information_atom.md)
- [Video media information header atom ('vmhd')](quicktime-file-format/video_media_information_header_atom.md)
- [Sound media information atom ('minf')](quicktime-file-format/sound_media_information_atom.md)
- [Sound media information header atom ('smhd')](quicktime-file-format/sound_media_information_header_atom.md)
- [Base media information atom ('minf')](quicktime-file-format/base_media_information_atom.md)
- [Base media info atom ('gmin')](quicktime-file-format/base_media_info_atom.md)
- [Data information atom ('dinf')](quicktime-file-format/data_information_atom.md)
- [Data reference atom](quicktime-file-format/media_data_reference_atom.md)