The Dubbing and Audio description Profiles of TTML2, by the Timed Text Working Group is a profile of TTML2 suitable for the scripting, voicing and audio mixing of dubbing tracks and audio description for video. This work was originally a combination of The Audio Description Profile of TTML2 , which was originally made by the Audio Description Community Group, and Timed Text Authoring Lineage (TTAL).
It is intended to meet the requirements set out in the Requirements for Dubbing and Audio description.
The Editor's Draft can be viewed at https://w3c.github.io/dapt/