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# Reference movie descriptor atom ('rmda')

An atom that contains other atoms that describe where to find a particular movie, the system requirements to play that movie, and a quality rating.

## Overview

The reference movie descriptor atom contains other atoms that describe where a particular movie can be found, and optionally what the system requirements are to play that movie, as well as an optional quality rating for that movie.

A reference movie descriptor atom’s parent is always a movie reference atom (`'rmra'`). Multiple reference movie descriptor atoms are allowed in a given movie reference atom, and more than one is usually present.

## Topics

### Data fields

[`Size`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Size)

The number of bytes in this reference movie descriptor atom.

[`Type`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Type)

The type of this atom.

[`Data reference atom`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Data_reference_atom)

Each reference movie atom must contain exactly one data reference atom.

[`Data rate atom`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Data_rate_atom)

A reference movie atom may contain an optional data rate atom.

[`CPU speed atom`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/CPU_speed_atom)

A reference movie atom may contain an optional CPU speed atom.

[`Version check atom`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Version_check_atom)

A reference movie atom may contain an optional version check atom.

[`Component detect atom`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Component_detect_atom)

A reference movie atom may contain an optional component detect atom.

[`Quality atom`](/documentation/quicktime-file-format/Reference_movie_descriptor_atom/Quality_atom)

A reference movie atom may contain an optional quality atom.


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