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# Edit atom ('edts')

An atom that defines the portions of the media that are to be used to build up a track for a movie.

## Overview

You use edit atoms to define the portions of the media that are to be used to build up a track for a movie. The edits themselves are contained in an edit list table, which consists of
time offset and duration values for each segment. Edit atoms have an atom type value of `'edts'`.

In the absence of an edit list, the presentation of a track starts immediately. An empty edit is used to offset the start time of a track.

> Note: If the edit atom or the edit list atom is missing, you can assume that the entire media is used by the track.

## Topics

### Data fields

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

A 32-bit integer that specifies the number of bytes in this edit atom.

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

A 32-bit integer that identifies the atom type.

[`Edit list atom`](/documentation/quicktime-file-format/Edit_atom/Edit_list_atom)

An atom that maps from a time in a movie to a time in a media, and ultimately to media data.


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