<!--
{
  "availability" : [

  ],
  "documentType" : "symbol",
  "framework" : "quicktime-file-format",
  "identifier" : "/documentation/quicktime-file-format/Subtitle_style_atom",
  "metadataVersion" : "0.1.0",
  "role" : "Atom",
  "symbol" : {
    "kind" : "Atom",
    "modules" : [
      "QuickTime File Format"
    ],
    "preciseIdentifier" : "__docc_universal_symbol_reference_$Subtitle_style_atom"
  },
  "title" : "Subtitle style atom ('styl')"
}
-->

# Subtitle style atom ('styl')

An atom that specifies changes to the appearance of a subtitle.

## Overview

This extension specifies changes to the appearance of a subtitle. The style information in the subtitle sample description provides the default style for the subtitle text. This extension allows you to override the default style for different parts, or all, of the subtitle text.

## Topics

### Data fields

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

An unsigned 32-bit integer holding the size of the subtitle style atom.

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

An unsigned 32-bit field.

[`Entry count`](/documentation/quicktime-file-format/Subtitle_style_atom/Entry_count)

An unsigned 16-bit integer specifying how many subtitle text style records follow this entry count.

[`Subtitle text style record`](/documentation/quicktime-file-format/Subtitle_style_atom/Subtitle_text_style_record)

One or more records that provide details about the subtitle’s style.


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)