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 1.9.1.
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 or an SRTXML document with the respective W3C XML Schema an XML Schema 1.0 parser is required. You could use e.g. xerces XML parser and validator.
For the conversion of an EBU STL file into STLXML (or the conversion of an SRT file into SRTXML) 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 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
- SRTXML-XSD
- SRT2SRTXML
- SRTXML2SRT
- SRTXML2TTML
- TTML2SRTXML
- EBU-TT-D-Basic-DE2WebVTT
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 SRTXML W3C XML Schema is a tool to check if the XML representation of the SRT (SubRip) files conform to the expected structure. Files that don't conform will most probably fail further SCF conversions or will otherwise lead to unexpected results.
The SRT2SRTXML script decodes the SRT file and exports it in an XML representation that can be used for further processing with XML technologies or for debugging purposes.
The SRTXML2SRT module converts an XML representation of SRT to an SRT text file.
The SRTXML2TTML XSLT transforms an XML representation of an SRT file into a TTML file, using a user-provided TTML template file. Hereby the template serves as a base for the conversion output into which the converted subtitles are inserted.
The TTML2SRTXML XSLT converts a TTML file that fulfils certain requirements into an XML representation of an SRT file.
Note that the SRT format is not based on a common official standard, but is a community driven format.
The EBU-TT-D-Basic-DE2WebVTT XSLT converts an EBU-TT-D-Basic-DE file into a WebVTT file, including text colors.
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.
Some modules use a different approach for testing (e.g. as the output format is not based on XML). In such a case the module contains separate testing instructions.
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, Andreas Tai
- 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)
- SubRip (SRT), accessed on 2020-03-18
- WebVTT: The Web Video Text Tracks Format