EBU STL Convert
May 9, 2023 ยท View on GitHub
The goal of this project is to convert an EBU STL (Tech 3264) binary file and produce equivalent web centric captioning formats.
Output formats supported:
- TTML text captions using regions for vertical placement and in-line text colour styling with spans
- WebVTT with vertical placement and colour support using cue::color styling
The script/convert_stl.sh uses bin/jar/STL2TTML.jar with groovy dependencies to run the application. All that is
required is a Java 8+ runtime in the path.
STL2TTML Options:
-f | -file STL file to process
-o | -offset number of seconds to add to the STL timing
-t | -ttml Create TTML file
-v | -vtt Create VTT file
-ns | -no-vtt-styling Disable all VTT Styling
-l | -log-level Logging level > 0 to produce output
-s | -safe-area VTT Vertical safe area precentage 0 .. 50
-z | -zero-timecode Remove any non-zero timecode reference from the STL captions
The safe-area option prevents the caption text from being rendered on the very top and bottom of the player area. The default value is set at 5% but can be disabled by setting -s 0 on the command line.
The zero-timecode option removes timecode offsets that are multiples of 1 hour added to the first valid timecode (firstInCue from the GsiBlock). Any text blocks before the firstInCue position are ignored when using this option flag.