<!--
{
  "availability" : [

  ],
  "documentType" : "symbol",
  "framework" : "QuickTime File Format",
  "identifier" : "/documentation/quicktime-file-format/Subtitle_sample_data",
  "metadataVersion" : "0.1.0",
  "role" : "Atom",
  "symbol" : {
    "kind" : "Atom",
    "modules" : [
      "QuickTime File Format"
    ],
    "preciseIdentifier" : "__docc_universal_symbol_reference_$Subtitle_sample_data"
  },
  "title" : "Subtitle sample data"
}
-->

# Subtitle sample data

An atom that contains subtitle sample data.

## Overview

Subtitle sample data consists of a 16-bit word that specifies the length (number of bytes) of the subtitle text, followed by the subtitle text and then by optional sample extensions. The subtitle text is Unicode text, encoded either as UTF-8 text or UTF-16 text beginning with a UTF-16 BYTE ORDER MARK (`'\uFEFF'`) in big or little endian order. There is no null termination for the text.

Following the subtitle text, there may be one or more atoms containing additional information for selecting and drawing the subtitle.

## Topics

### Data fields

[`Text size`](/documentation/quicktime-file-format/Subtitle_sample_data/Text_size)

A 16-bit word that specifies the length (number of bytes) of the subtitle text.

[`Text`](/documentation/quicktime-file-format/Subtitle_sample_data/Text)

The subtitle text.

[`Sample extensions`](/documentation/quicktime-file-format/Subtitle_sample_data/Sample_extensions)

One or more atoms containing additional information for selecting and drawing the subtitle.


---

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)