| WebVTT | |
|---|---|
| Filename extension | .vtt |
| Internet media type | text/vtt |
| Developed by | World Wide Web Consortium (W3C) |
| Initial release | 10 August 2010; 15 years ago (2010-08-10)[1] |
| Latest release | 4 April 2019; 6 years ago (2019-04-04) |
| Type of format | Timed text |
| Extended from | SRT |
| Standard | W3C WebVTT |
| Open format? | Yes |
| Free format? | Yes |
WebVTT (Web Video Text Tracks) is aWorld Wide Web Consortium (W3C) standard for displayingtimed text in connection with theHTML5<track> element.
The early drafts of its specification were written by theWHATWG in 2010 after discussions about what caption format should be supported by HTML5—the main options being the relatively mature,XML-basedTimed Text Markup Language (TTML) or an entirely new but more lightweight standard based on the widely usedSubRip 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 the SubRip format, though not fully compatible with it.[3]The prospective format was later renamed WebVTT.[4][5] In the January 13, 2011, version of the HTML5 Draft Report, the<track> element was introduced and the specification was updated to document WebVTT cue text rendering rules.[6] The WebVTT specification is a W3C Candidate Recommendation, and the basic features are supported by all major browsers.
| Browser | Cue Text Tags | Cue Positioning | CSS Styling |
|---|---|---|---|
| Chrome | 35+ | ||
| Android stock browser | 5.0+ | ||
| Opera | 22+ | ||
| Safari | 7+ (iOS: 8+) | ||
| Firefox | 31+ (Android: 32+) | N/a | |
| Microsoft Edge | 12+ | N/a | |
| Internet Explorer | 10+ | N/a | |
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.[10] YouTube began supporting WebVTT in April, 2013.[11] As of July 24, 2014, Mozilla has enabled WebVTT on Firefox by default.[12]
Subtitles in a .vtt file show online, but not when stored on a local drive.
A sample file from the W3C captioningRoger Bingham interviewingNeil deGrasse Tyson ([1]):[13]
WEBVTT00:11.000 --> 00:13.000<v Roger Bingham>We are in New York City00:13.000 --> 00:16.000<v Roger Bingham>We're actually at the Lucern Hotel, just down the street00:16.000 --> 00:18.000<v Roger Bingham>from the American Museum of Natural History00:18.000 --> 00:20.000<v Roger Bingham>And with me is Neil deGrasse Tyson00:20.000 --> 00:22.000<v Roger Bingham>Astrophysicist, Director of the Hayden Planetarium00:22.000 --> 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:right size:50%<v Roger Bingham>When we e-mailed—00:30.500 --> 00:32.500 align:left size:50%<v Neil deGrasse Tyson>Didn't we talk about enough in that conversation?00:32.000 --> 00:35.500 align:right size:50%<v Roger Bingham>No! No no no no; 'cos 'cos obviously 'cos00:32.500 --> 00:33.500 align:left 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.
In June 2013, an example was added to the specification that included a new "region" setting.[14] This feature is supported since Firefox 59 and Safari 14.1 (14.5 on iOS) but not in any other browser.[15]