WebVTT

WebVTT
Filename extension not specified
Internet media type text/vtt
Developed by W3C
Initial release 10 August 2010 (2010-08-10)[1]
Type of format Timed text
Extended from SRT
Standard W3C WebVTT
Open format? Yes

WebVTT (Web Video Text Tracks) is a W3C standard for displaying timed text in connection with the HTML5 <track> element. The early drafts of its specification were written by WHATWG in 2010, after discussions about what caption format should be supported by HTML5, the main options being the relatively mature, XML-based TTML or an entirely new but more lightweight standard based on the popular SRT format. The final decision was for the new standard, initially called WebSRT (Web Subtitle Resource Tracks).[2] It shared the .srt file extension and was "broadly based on" (parts of) the SubRip format, though not fully compatible with it.[3][4] The prospective format was later renamed WebVTT.[5][6] In the January 13, 2011 version of the HTML5 Draft Report, the <track> tag was introduced and the specification was updated to document WebVTT cue text rendering rules. The WebVTT specification is still in draft stage but the basic features are already supported by all major browsers.

Main differences from .srt

Compatibility

Browser Support[8]
BROWSER CUE POSITIONING CUE TEXT TAGS CSS STYLING
Firefox for Desktop 31+ 31+ -
Chrome for Desktop 35+ 35+ 35+
Safari for Mac 7+ 7+ 7+
Opera for Desktop 22+ 22+ 22+
Internet Explorer for Windows - - -
Safari for iOS 8+ 8+ 8+
Stock Browser for Android 5.0+ 5.0+ 5.0+
Chrome for Android 35+ 35+ 35+
Firefox for Android 32+ 32+ -
Internet Explorer for Winphone - - -

Firefox implemented WebVTT in its nightly builds (Firefox 24), but initially it was not enabled by default. The feature had to be enabled in Firefox by going to the "about:config" page and setting the value of "media.webvtt.enabled" to true.[9] YouTube began supporting WebVTT in April, 2013.[10] As of July 24, 2014, Mozilla has enabled WebVTT on Firefox by default.[11]

Example of WebVTT format

WEBVTT
00:09.000 --> 00:11.000
<v Roger Bingham>We are in New York City

00:11.000 --> 00:13.000
<v Roger Bingham>We are in New York City

00:13.000 --> 00:16.000
<v Roger Bingham>We're actually at the Lucern Hotel, just down the street

00:16.000 --> 00:18.000
<v Roger Bingham>from the American Museum of Natural History

00:18.000 --> 00:20.000
<v Roger Bingham>And with me is Neil deGrasse Tyson

00:20.000 --> 00:22.000
<v Roger Bingham>Astrophysicist, Director of the Hayden Planetarium

00:22.000 --> 00:24.000
<v Roger Bingham>at the AMNH.

00:24.000 --> 00:26.000
<v Roger Bingham>Thank you for walking down here.

00:27.000 --> 00:30.000
<v Roger Bingham>And I want to do a follow-up on the last conversation we did.

00:30.000 --> 00:31.500 align:end size:50%
<v Roger Bingham>When we e-mailed—

00:30.500 --> 00:32.500 align:start size:50%
<v Neil deGrasse Tyson>Didn't we talk about enough in that conversation?

00:32.000 --> 00:35.500 align:end size:50%
<v Roger Bingham>No! No no no no; 'cos 'cos obviously 'cos

00:32.500 --> 00:33.500 align:start size:50%
<v Neil deGrasse Tyson><i>Laughs</i>

00:35.500 --> 00:38.000
<v Roger Bingham>You know I'm so excited my glasses are falling off here.

Unsupported features

In June 2013 an example was added to the other features section of the specification that included a new "region" setting.[12] As of February 2015, however, no player included support for this feature.

References

  1. "WebSRT". Archived from the original on 2010-08-16. Retrieved 2015-02-12.
  2. "WebVTT versus TTML: XML considered harmful for web captions?". Retrieved 16 February 2015.
  3. Understanding WebSRT format
  4. WebSRT, from the WHATWG HTML draft specification, retrieved 2010-10-14
  5. Kennedy, Antony; de Leon, Inayaili (2011). Pro CSS for High Traffic Websites. Apress. ISBN 978-1-4302-3288-9.
  6. Pfeiffer, Silvia (June 27, 2011). "Recent developments around WebVTT".
  7. "WebVTT cue settings". W3C. Retrieved 11 February 2015.
  8. "WebVTT Styling". JWPlayer. Retrieved 23 February 2015.
  9. "Implement the track element".
  10. "Caption File - YouTube Help".
  11. "Firefox 31 Release Notes".
  12. "Added region example to Introduction section under "Other features" – GitHub commit details".

External links

This article is issued from Wikipedia - version of the Tuesday, March 08, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.