Subtitles (commonly written as Sub-Titles or abbreviated as subs; referred to as Captions when the text displayed is the same language or a dialect/slang clarification of same-language on-screen dialogue) are a translation from the original language of a given piece of multimedia into a different language for the benefit of any viewers who may not understand the original language.
Subtitles require one to be able to read as quickly as the original multimedia is spoken or otherwise presented, since their purpose is to always (at least in a general sense) provide a literary or equivalent translation of the exact words being spoken or otherwise presented.
A prime example of subtitles is the "Sub-Title" option available on most theatrical movie releases (where a movie is released in a foreign country and/or language), as well as commercial DVDs or Blu-Ray disks; the former of which will typically only be available in the most commonly spoken language or national language(s) of a given country where a movie is playing, and the later of which will typically provide the widest practical selection of langauges (based on the production's popularity and post-production budget).
- W3C TimedText Markup Language (TTML) 1.0 format: http://www.w3.org/TR/ttaf1-dfxp/
- 3GPP Timed Text (TTXT) format: http://gpac.wp.institut-telecom.fr/mp4box/ttxt-format-documentation/
- Web Video Text Tracks (WebVTT) format: http://dev.w3.org/html5/webvtt/
- SRT Subtitles: http://matroska.org/technical/specs/subtitles/srt.html
- YouTube's SBV Subtitle Export format: http://support.google.com/youtube/bin/answer.py?hl=en&answer=100077
- Sub Station Alpha (SSA): http://matroska.org/technical/specs/subtitles/ssa.html
- dotSub: http://dotsub.com
- Subtitle Horse (flash): http://subtitle-horse.org
- Universal Subtitles (js): http://universalsubtitles.org/en/
- YouTube SBV Subtitles to Universal SRT converter: http://www.dcmp.org/ciy/converting-youtube-to-srt.html
- OpenTranslation Project: http://www.ted.com/index.php/OpenTranslationProject
- periscope -- Python module searching subtitles on the web: http://code.google.com/p/periscope/ (Used in plugins for the GNOME desktop)
- How to watch movies with subtitles?: http://blog.opensubtitles.org/other/how-to-watch-movies-with-subtitles
- Creating Kate Streams - Text movie subtitles: http://code.google.com/p/libkate/wiki/CreatingKateStreams | DEMO
- YouTube SBV Subtitles Export format: http://webdev-il.blogspot.com/2010/01/sbv-file-format-for-youtube-subtitles.html
- Video Subtitling and WebVTT: http://html5doctor.com/video-subtitling-and-webvtt/