EBU-STL (EBU Subtitling Data Exchange Format)
- .stl
- Read
- Write
Closed Caption Converter reads and writes EBU-STL files. Convert EBU-STL to and from 56 other caption and subtitle formats in the web app, with the REST API, or offline with the CLI.
What is an EBU-STL file?
EBU-STL is the subtitle exchange format defined by the European Broadcasting Union in EBU Tech 3264-E (1991). For more than three decades it has been the common file format between subtitling software, broadcasters and playout systems across Europe and beyond, for both teletext and open (burned-in) subtitles.
An STL file is binary. It starts with a 1024-byte General Subtitle Information (GSI) block that describes the whole file. The GSI holds the frame rate, character code table, language, programme and episode titles, translator and editor details, the maximum characters per row, and the start-of-programme timecode. After the GSI come Text and Timing Information (TTI) blocks of 128 bytes each. Each TTI block holds a subtitle’s in-cue and out-cue timecodes, vertical position, justification and up to 112 bytes of text, including teletext control codes for color and double height.
Because the header carries so much metadata, broadcasters often require specific GSI values: a particular language code, country of origin or maximum row length. A conversion that leaves them at defaults can fail ingest even when the subtitles themselves are perfect.
Key GSI fields
| Field | What it controls |
|---|---|
| Disk Format Code (DFC) | Frame rate: STL25.01 or STL30.01 |
| Display Standard Code (DSC) | Open subtitles or teletext level 1/2 |
| Character Code Table (CCT) | Which character set the subtitle text uses |
| Language Code (LC) | Language of the subtitles |
| Original/Translated Programme & Episode Titles | Programme identification |
| Country of Origin (CO) | Three-letter country code |
| Maximum Number of Displayable Characters (MNC) | Maximum characters per row |
| Time Code: Start-of-Programme (TCP) | Programme start timecode, often 10:00:00:00 |
Closed Caption Converter exposes these as EBU-STL encoding options. Setting an option to auto copies the value from the source file’s metadata when one exists.
Convert EBU-STL files
Every readable format converts to every writable format, through the web app, the API or the CLI.
Popular EBU-STL conversions
Convert EBU-STL to
- Cavena 890
- iTT
- Closed Caption Creator Project
- Caption Inc.
- LMS Transcript
- JSON
- Substation Alpha
- Advanced Substation Alpha
- SCC
- MCC
- Rich Text Format
- SRT
- WebVTT
- Subviewer
- Sofni
- Micro DVD
- DVD Architect
- Avid DS
- Adobe Encore
- Apple DVD Studio Pro
- EZ Title
- PowerPixel Format
- ProCap Transfer
- QuickTime Text
- Eclipse
- Spruce STL
- PAC
- Cheetah (binary)
- Videotron Lambda
- NCI Caption
- Cheetah (ASCII Text)
- TTML
- DFXP
- DLP Cinema
- Netflix TT Captions
- Netflix TT Subtitles
- MAGIC TT
- EBU-TT
- SMPTE-TTML
- IMSC Text Captions
- IMSC Text Subtitles
- DCDM Subtitle
- Verizon TTML
- Bento MP4-DASH IMSC
- Netflix DFXP
- Synchronized Accessible Media Interchange
- Comma-Separated Values
- As-Broadcast Dialog List
Convert to EBU-STL from
- Cavena 890
- iTT
- Closed Caption Creator Project
- Caption Inc.
- LMS Transcript
- JSON
- Substation Alpha
- Advanced Substation Alpha
- SCC
- MCC
- Rich Text Format
- SRT
- WebVTT
- Subviewer
- Canvass SST Project
- Sofni
- Micro DVD
- DVD Architect
- Avid DS
- Adobe Encore
- Apple DVD Studio Pro
- EZ Title
- PowerPixel Format
- ProCap Transfer
- QuickTime Text
- Eclipse
- Spruce STL
- PAC
- Cheetah (binary)
- Videotron Lambda
- NCI Caption
- Cheetah (ASCII Text)
- TTML
- DFXP
- DLP Cinema
- Netflix TT Captions
- Netflix TT Subtitles
- MAGIC TT
- EBU-TT
- SMPTE-TTML
- IMSC Text Captions
- IMSC Text Subtitles
- DCDM Subtitle
- Verizon TTML
- Bento MP4-DASH IMSC
- Netflix DFXP
- Synchronized Accessible Media Interchange
- Comma-Separated Values
- Google STT Transcript
- Assembly AI STT Transcript
- Deepgram STT Transcript
- RevAI STT Transcript
- Voicegain STT Transcript
- Speechmatics STT Transcript
- Vitac
EBU-STL questions
EBU-STL is binary, so a text editor shows mostly unreadable bytes. Open it in subtitling software, or convert it to a text format such as SRT or EBU-TT to read and edit it. See EBU-STL to SRT.
No. Spruce STL is a plain-text format from Apple’s DVD Studio Pro and Spruce authoring tools that happens to share the .stl extension. Closed Caption Converter has separate profiles for each.
Broadcast masters usually start at 10:00:00:00, and STL timecodes follow the programme timecode. The GSI records this as the start-of-programme timecode. When converting for web use, apply a timecode offset to move the subtitles back to zero.
Convert your EBU-STL files in minutes
Upload a file in the web app, or automate conversions with the API and CLI. No credit card required to start.