| Filename extension |
.ttml, .dfxp, .xml |
|---|---|
| Internet media type |
application/ttml+xml |
| Developed by | W3C |
| Initial release | 1 November 2004[1] |
| Type of format | Timed text |
| Extended from | XML |
| Standard | W3C TTML1 |
| Open format? | Yes |
Timed Text Markup Language (TTML), previously referred to as Distribution Format Exchange Profile (DFXP), is an XML-based W3C standard for timed text in online media and was designed to be used for the purpose of authoring, transcoding or exchanging timed text information presently in use primarily for subtitling and captioning functions. TTML2, the second major revision of the language, was finalized on November 8, 2018. It has been adopted widely in the television industry, including by Society of Motion Picture and Television Engineers (SMPTE), European Broadcasting Union (EBU), ATSC, DVB, HbbTV and MPEG CMAF and several profiles and extensions for the language exist nowadays.
TTML Content may also be used directly as a distribution format and is widely supported in media players, with the exception of major web browsers, where WebVTT, the second W3C standard for timed text in online media, has better built-in support in connection with the HTML5 <track> element; many organisations nevertheless use TTML content on web video using their own player code.