World Library  
Flag as Inappropriate
Email this Article
 

Timed text

Timed text refers to the presentation of text media in synchrony with other media, such as audio and video.

Contents

  • Applications 1
  • Markup language specifications 2
  • Competing formats 3
  • Example 4
  • See also 5
  • References 6
  • External links 7

Applications

Typical applications of timed text are the real time subtitling of foreign-language movies on the Web, captioning for people lacking audio devices or having hearing impairments, karaoke, scrolling news items or teleprompter applications.

Timed text for MPEG-4 movies and cellphone media is specified in MPEG-4 Part 17 Timed Text, and its MIME type is specified by RFC 3839.

Markup language specifications

The W3C keeps two standards intended to regulate timed text on the internet: the Timed Text Markup Language (TTML)[1] and WebVTT[2] (currently in draft stage). SMPTE created additional metadata structures for use in TTML and developed a profile of TTML called SMPTE-TT.[3] The DECE incorporated the SMPTE Timed Text in their UltraViolet Common File Format specification.

Competing formats

Interoperability for timed text came up during the development of the SMIL 2.0 specification. Today, incompatible formats for captioning, subtitling and other forms of timed text are used on the Web. This means that when creating a SMIL presentation, the text portion often needs to be targeted to a particular playback environment. Moreover, the accessibility community relies heavily on captioning to make audiovisual content accessible. The lack of an interoperable format adds a significant additional cost to the costs of captioning Web content, which are already high.

Example

The following is an extract from the , in SubRip format, for the 1916 Krazy Kat Bugolist film.

1
00:00:22,000 --> 00:00:27,000
I'll teach thee Bugology, Ignatzes

2 
00:00:40,000 --> 00:00:43,000 
Something tells me

3 
00:00:58,000 --> 00:01:59,000 
Look, Ignatz, a sleeping bee

The equivalent in W3C WebVTT is the following:

WEBVTT

00:22.000 --> 00:27.000
I'll teach thee Bugology, Ignatzes

00:40.000 --> 00:43.000 
Something tells me

00:58.000 --> 01:59.000 
Look, Ignatz, a sleeping bee

The equivalent in W3C TTML is the following:

 
  
   

I'll teach thee Bugology, Ignatzes

Something tells me

Look, Ignatz, a sleeping bee

See also

References

  1. ^ Glenn Adams (Ed.): Timed Text Markup Language (TTML) 1.0 - W3C Recommendation, 18 November 2010
  2. ^ WebVTT Draft Report
  3. ^ SMPTE (August 2010), ST-2052-1; SMPTE Timed Text, Copyright © 2010 SMPTE. August 2010 (PDF), retrieved 2011-03-25 

External links

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.