Caption conversion

Convert EBU-STL to EBU-TT

EBU-STL (EBU Subtitling Data Exchange Format) to EBU-TT (EBU Timed Text). Convert in the web app, automate with the REST API, or run it offline with the CLI.

Convert EBU-STL to EBU-TT free How to convert

Converting EBU-STL to EBU-TT moves binary teletext-era subtitles to the EBU’s XML successor format. The EBU designed this path: EBU Tech 3360 defines how each STL field and control code maps into EBU-TT. It is the standard route for archive migration and modern subtitle exchange.

What carries over

Subtitle text, decoded to Unicode
SMPTE timecode at the STL frame rate
Teletext colors and double height, mapped to TTML styles
Vertical position, mapped to regions
GSI metadata, such as programme titles, language and publisher, when the encoding options are set to auto

What changes

Binary GSI fields become XML metadata in ebuttm:documentMetadata
Teletext-specific control codes without a TTML equivalent are not carried over

How to convert EBU-STL to EBU-TT

The same conversion engine powers all three, so a job you set up in the web app produces identical output from the API or CLI.

In the web app

Sign in to the web app, or start a free trial.
Upload your .stl file and select EBU STL as the source profile.
Select EBU TT as the target profile.
Review the recommended settings for this conversion.
Run the conversion and download your .xml file.

With the API

POST /jobs

curl -X POST https://api.closedcaptionconverter.com/jobs \
  -H "x-api-key: YOUR_API_KEY" \
  -F "source=@input.stl" \
  -F 'config={
    "job_type": "convert",
    "source_profile": "EBU STL",
    "target_profile": "EBU TT",
    "encoding_options": [
      {
        "name": "Language Code",
        "selected": "auto"
      }
    ]
  }'

See API Getting Started for authentication and response handling.

With the CLI

Command line

ccconverter \
  --source input.stl \
  --target output.xml \
  --source_profile "EBU STL" \
  --target_profile "EBU TT" \
  --source_frameRate 25

The CLI runs fully offline on macOS, Windows and Linux. See the CLI docs for every flag.

Recommended settings

Metadata options	Set Language Code and title fields to `auto` to copy them from the STL GSI header.
Frame rate	Keep the source rate (normally 25 fps).

Format-specific options are covered in Encoding & Decoding Options and Profiles & Formats.

EBU-STL to EBU-TT questions

EBU-TT supports Unicode, richer styling and XML tooling, and is the basis for online distribution through EBU-TT-D. STL’s fixed character tables and 112-byte text blocks are a constraint for modern workflows.

Yes, when you set the EBU-TT encoding options to auto. Closed Caption Converter reads the GSI header (language, titles, translator, publisher) and writes the matching EBU-TT metadata.

Yes, as long as the text fits an STL character table and the row-length limits. Styling beyond teletext’s capabilities is simplified.

Learn more about these formats

Source

EBU-STL (EBU Subtitling Data Exchange Format)

What an EBU-STL (.stl) subtitle file is, how the EBU Tech 3264 GSI header and TTI blocks work, frame rates and character tables, and how to convert STL files.

Target

EBU-TT (EBU Timed Text)

What an EBU-TT subtitle file is, how the EBU’s TTML-based format (Tech 3350) replaces EBU-STL, how EBU-TT-D differs, and how to convert EBU-TT files.

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