W3C | Submissions

Team Comment on the “TTML Text and Image Profiles for Internet Media Subtitles and Captions” Submission


The W3C is pleased to receive the “TTML Text and Image Profiles for Internet Media Subtitles and Captions” submission from MovieLabs edited by Pierre Lemieux.

The W3C Timed Text Working Group published Timed Text Markup Language (TTML) 1.0 in December 2010 and has been working on a second edition. In February 2013, the Working Group published TTML Simple Delivery Profile for Closed Captions (US), a profile intended to establish a minimum level of interoperability between Timed Text 1.0 and legacy caption formats employed in US markets, such as CEA608 and CEA708. While it is a step forward in promoting interoperability around the TTML format, that profile addresses only one segment of the captioning market.

The submitted specification introduced two new profiles intended to be used worldwide. As a superset of SDP-US addressing a worldwide market, the new profiles attempt to further promote interoperability around Timed Text 1.0. However, the submission introduces two new profiles, text and image, without resolving the differences between the Common File Format & Media Formats Specification (CFF) and the SMPTE-TT extensions. As such, it increases the number of profiles available around Timed Text 1.0 rather than encouraging convergence.

The Timed Text Working Group is chartered to work on Timed Text 1.1 and will consider for adoption features developed by groups such as SMPTE, DECE and EBU, and it seems beneficial for the industry to encourage the convergence at that level.

Next Steps

As of today, the Timed Text Working Group is about to start working in earnest on TTML 1.1, following a long period of work on SDP-US and TTML 1.0 secend edition. However, there have been discussions to recharter to include work on WebVTT: The Web Video Text Tracks Format, published by the Text Tracks Community Group and originally created by the WHATWG. As part of the rechartering, it would be beneficial to add the text and image profile from the submitted specification for further consideration.

We encourage people interested by this work to discuss on the public-tt@w3.org [public archive] mailing list.

Disclaimer: Placing a Submission on a Working Group agenda does not imply endorsement by either the W3C Staff or the participants of the Working Group, nor does it guarantee that the Working Group will agree to take any specific action on a Submission.

Philippe Le Hégaret, Timed Text Team Contact <plh@w3.org>