Integrating an end-to-end subtitling solution has just become easier for vendors and broadcasters. With the version 1.0 release of EBU-TT Parts 2 and 3, the format now covers the complete chain from authoring to distribution, for both live and prepared subtitling.

The new publications are part of a package of recent EBU-TT releases. Together these standards allow for the implementation of customizable solutions that deliver subtitles all the way from an author's terminal or microphone to audiences' screens.

EBU-TT Part 1

All EBU-TT work builds on this core format specification (EBU Tech 3350), which has now reached version 1.2. This new version includes clarifications on various topics, introduces an easier way to deal with metadata extensions and is aligned with the latest releases of all related specifications.


The EBU-TT metadata elements are now defined in a single, new document (EBU Tech 3390). This makes it easier to maintain an overview and avoid duplication.

EBU-TT Part 2

This publication (Tech 3360) covers strategies for converting existing EBU STL (Tech 3264) files into their modern EBU-TT counterparts. The document is rich in explanation and helps to make the right choices when converting legacy content. This is the first official release of EBU-TT Part 2.

EBU-TT Part 3

Also known as EBU-TT Live, EBU-TT Part 3 (Tech 3370) specifies how to carry and distribute EBU-TT subtitle streams in production facilities. It defines a flexible collection of nodes that can be used to build customized processing chains. For example, one or more authoring stations could be set up to send subtitle streams to a distribution encoder and an archive. Both live and prepared subtitles are supported.

EBU-TT WebSocket Carriage Specification

EBU-TT Live does not prescribe which carrier mechanisms to use. These mechanisms can be defined in supplemental publications. EBU Tech 3370s1 is such a supplement. It describes how to carry EBU-TT-Live streams using WebSocket.

EBU-TT Live Interoperability Toolkit

This is not an official EBU spec, but an Open Source project that builds on the EBU-TT Live spec. It was used to test the specification in code and is a useful resource when adding EBU-TT Live support to products. See for more.


EBU-TT-D (Tech 3380) and its ISOBMFF mapping (Tech 3381) both remain the same. These are the only two documents in the EBU-TT family that were not updated in this recent round – simply because there was no need to do so.

For more information see:

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