The Subtitling Conversion Framework (SCF) is a set of modules for converting XML based subtitle formats. Main target is to build up a flexible and extensible transformation pipeline to convert EBU STL formats and EBU-TT subtitle formats.

The SCF is a stable release with the version 1.6.0.

The Subtitle Conversion Framework ("SCF") offered by Institut fuer Rundfunktechnik on GitHub is subject to the Apache 2.0 license.

For the XSLT modules an XSLT processor that is conformant to XSLT 1.0 is needed. You could use for example a Saxon XSLT processor from version 6.5.5.

The STLXML2EBU-TT, EBU-TT2STLXML and STLXML-SplitBlocks modules require XSLT 2.0 support. For the STLXML2EBU-TT and EBU-TT2STLXML modules EXSLT support can be used as fallback.

To validate an STLXML document with the STLXML W3C XML Schema an XML Schema 1.0 parser is required. You could use for example xerces XML parser and validator.

For the conversion of an EBU STL file into STLXML Python 3 is required (it will not run under Python 2).

Each module has its own directory under the "modules" folder:

---modules
  +---EBU-TT2EBU-TT-D
  +---STLXML2EBU-TT
  +---STLXML-XSD

The main artefact is in the root of the respective module folder:

  +---EBU-TT2EBU-TT-D
    |   EBU-TT2EBU-TT-D.xslt

In addition a README file is provided for every module.

Apart from the artefacts the module folder contains a folder with test files and optionally a folder with source code that tests the respective test files (e.g. Schematron files with assertions to validate XML based output).

+---EBU-TT2EBU-TT-D
|       \---tests
|         +---schema
|         +---test_files

The SCF also provides a REST service including a simple web interface. This service invokes the different conversion modules of the SCF.

For further details, please see README-SCF-SERVICE.md.

Currently the SCF has the following eight core modules:

• STLXML-XSD
• STL2STLXML
• STLXML-SplitBlocks
• STLXML2STL
• STLXML2EBU-TT
• EBU-TT2STLXML
• EBU-TT2EBU-TT-D
• EBU-TT-D2EBU-TT-D-Basic-DE
• FlashDFXP2EBU-TT-D-Basic-DE

Additionally there are various helper submodules that can be found in the folder "TT-Helper". These modules solve smaller transformation tasks.

The STLXML W3C XML Schema is a tool to check if the XML representation of the EBU STL files conform to the expected structure. Files that don't conform will most probably fail the STLXML to EBU-TT conversion or will lead to unexpected results.

The STL2STLXML script decodes the EBU STL file and exports it in an XML representation that can be used for further processing with XML technologies or for debugging purposes.

The STLXML-SplitBlocks module splits TTI blocks that exceed the maximum Text Field (TF) size in EBU STL. It should be applied to an STLXML file before processing that file with STLXML2STL.

The STLXML2STL module converts an XML representation of EBU STL to a binary file that conforms to EBU STL.

The STLXML2EBU-TT XSLT transforms an XML representation of an EBU STL file into an EBU-TT file that conforms to EBU Tech 3350 (EBU-TT Part 1). It follows the guideline provided by EBU Tech 3360 version 0.9.

The EBU-TT2STLXML XSLT converts EBU-TT Part 1 files that have been created according to EBU Tech 3360 into an XML representation of an EBU STL file.

The EBU-TT2EBU-TT-D XSLT converts EBU-TT Part 1 files that have been created according to EBU Tech 3360 into EBU-TT-D files that conform to EBU Tech 3380.

The EBU-TT-D2EBU-TT-D-Basic-DE XSLT converts EBU-TT-D files that have been created according to EBU Tech 3380 into EBU-TT-D-Basic-DE files that conform to the "XML-Format for Distribution of Subtitles in the ARD Mediathek portals" (EBU-TT-D-Basic-DE).

The FlashDFXP2EBU-TT-D-Basic-DE module converts a TTML/DFXP file made for Adobe Flash player into EBU-TT-D-Basic-DE.

The test files that are used as test input for a module are named according to the following pattern:

requirement-[id of requirement]-[number of test for this requirement].[file suffix]

Example: The first test file for the requirement 27 in an XML format is named requirement-0027-001.xml.

If there are certain assertions written that can be automatically processed (e.g. by a schematron schema), then each assertion file has the corresponding file name of the test file (with file suffix of the assertion format).

A schematron file that tests the output of a module that gets the test file requirement-0027-001.xml as input would be named as requirement-0027-001.sch.

A documentation draft of all modules can be found in the folder documentation.

Furthermore each module contains in a documentation folder the requirements for the implementation and the current status. All modules are implemented according to these requirements. Thus any further features (e.g. conversion of non-Teletext subtitles) are not (intentionally) supported.

Development: Tilman Eberspächer, Andreas Tai, Barbara Fichte, Dominik Garsche, Stefan Pöschel, Peter tho Pesch, Lukas Kircher

Test files: Barbara Fichte, Lilli Weiss, Tilman Eberspächer, Stefan Pöschel, Peter tho Pesch

QC: Stefan Pöschel, Barbara Fichte, Peter tho Pesch

• EBU STL (EBU Tech 3264)
• MAPPING EBU STL TO EBU-TT SUBTITLE FILES (EBU Tech 3360)
• EBU-TT-D SUBTITLING DISTRIBUTION FORMAT (EBU Tech 3380)
• XML-Format for Distribution of Subtitles in the ARD Mediathek portals (EBU-TT-D-Basic-DE)