A Subtitle editor is a type of software used to create and edit subtitles

Subtitle (captioning)

Subtitles are textual versions of the dialog in films and television programs, usually displayed at the bottom of the screen. They can either be a form of written translation of a dialog in a foreign language, or a written rendering of the dialog in the same language, with or without added...

 to be superimposed over, and synchronized with, video. Such editors usually provide video preview, easy entering/editing of text, start, and end times, and control over text formatting and positioning. Subtitle editors are available as standalone applications, as components of many video editing software suites, and as web applications.

Purpose

In television, subtitles are used for "clarification, translation, services for the deaf, as well as identifying places or people in the news." In movies, subtitles are mainly used for translations from foreign languages.
Subtitles are frequently used to provide informative details regarding the action on screen, such as the names and titles of interview subjects, a discussion topic change, to spell out web URLs or email addresses, to assist understanding speakers who mumble, details in instructional videos such as recipe ingredients, and humorous effects such as commentary or contradictory captions.

Each subtitle, during editing, consists of text, a start time, an end time or duration, and optional text styling and positioning.

Time is measured either in video frames, in milliseconds, or in hours:minutes:seconds.frames/milliseconds. The exact format and separator characters(colon, period, comma, etc.) are determined by the subtitle format chosen. A capable subtitle editor can convert one time measurement system into another without error.

Editor features

A subtitle editing tool will typically have these features:

• Capable of displaying a variety of video formats, loading and saving a wide variety of subtitle file formats
• Video preview: simultaneous, synchronized playback of video and subtitles, with pause/play and fine adjustment over video: jog/shuttling/slow-motion
• Text entry and editing
  • Search and replace of text to correct names, etc.
  • Spell check
  • Change text encoding for UTC-8, Unicode, etc.
• Change the duration of a given subtitle's display
• Shift subtitles or a block of subtitles back and forth in time
• Change subtitle format (MicroDVD
  MicroDVD
  MicroDVD is a subtitle file format for digital video. Its name is derived from a media player application designed to play DVD videos along with subtitles, originally developed by Tiamat Software. The application was first released in 2000 but development ended in 2001...
  
  , MPSub, SubRip
  SubRip
  SubRip is a software program for Windows which "rips" subtitles and their timings from video. It is free software, released under the GNU GPL...
  
  , ...)
• Changing the time base frame rate
  Frame rate
  Frame rate is the frequency at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems...
  
   24, 25, 29.995, 30, etc.

Not all editors are equally flexible in terms of video formats, subtitle formats, or ease of use.

Examples of subtitle editors

Web-based

• Universal Subtitles - licensed under Affero GPL
• Online Subtitles Workshop (team edition). Free PHP/Javascript system.

Cross-platform

• Aegisub
  Aegisub
  Aegisub is a free open-source cross-platform subtitle editing program. It is extensively used in fansubbing, the practice of creating or translating unofficial, noncommercial subtitles for visual media by fans...
  
   - Free. GNU/Linux, OS X, Windows
• Jubler - Free. Jubler.org. GNU/Linux, OS X, Windows (Java).
• Gaupol Subtitle Editor - Free. GNA. GNU/Linux, Windows, OSX(untested). (Python).

GNU/Linux

• Gnome Subtitles
  Gnome Subtitles
  Gnome Subtitles is an open-source subtitle editor forthe GNOME desktop, based on Mono. It supports the most common text-based subtitle formats, video previewing, timings synchronization and subtitle translation...
  
   - Free.
• Subtitle Editor - Free. For Gnome desktop. GNA.

Windows

• CaptionMaker - commercial. CPC.
• Pers-o-Subtitle Tools
• Subrip
  SubRip
  SubRip is a software program for Windows which "rips" subtitles and their timings from video. It is free software, released under the GNU GPL...
  
   - Free
• Subtitle Edit - Free and Open Source
  Open source
  The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
  
   under GPL License
• Subtitle Studio (Untertitelstudio)- Free (German). Simon Lehmayr.
• Subtitle Tool - Free. Tom Zavodny.
• Subtitle Workshop - Free and version 2.51 is Open Source
  Open source
  The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
  
   under GPL License. UruSoft.
• WinCAPS Multimedia by Sysmedia - commercial.
• VisualSubSync - Free.

Mac OS X

• MacCaption - commercial. CPC.
• MovieCaptioner - commercial.

Related software

• VobSub/VSFilter/DirectVobSub - not an editor, but a Windows add-on (DirectX
  DirectX
  Microsoft DirectX is a collection of application programming interfaces for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with Direct, such as Direct3D, DirectDraw, DirectMusic, DirectPlay,...
  
   filter) which displays subtitles during video playback.

External links

• Díaz-Cintas, Jorge (2008). The Didactics of Audiovisual Translation (Benjamins Translation Library). John Benjamins Publishing Co., p. 98. ISBN: 978-9027216861.