PgsToSrt

Convert PGS subtitles to SRT using OCR.

Prerequisites

• .NET 8.0 Runtime
• Tesseract 4 language data files

Data files must be placed in the tessdata folder inside PgsToSrt folder, or the path can be specified in the command line with the --tesseractdata parameter.

You only need data files for the language(s) you want to convert.

Usage

dotnet PgsToSrt.dll [parameters]

Parameter	Description
--input	Input filename, can be an mkv file or pgs subtitle extracted to a .sup file with mkvextract.
--output	Output SubRip (.srt) filename. Auto generated from input filename if not set.
--track	Track number of the subtitle to process in an .mkv file (only required when input is a matroska file) This can be obtained with mkvinfo
--tracklanguage	Convert all tracks of the specified language (only works with .mkv input)
--tesseractlanguage	Tesseract language to use if multiple languages are available in the tesseract data directory.
--tesseractdata	Path of tesseract language data files, by default tessdata in the executable directory.
--tesseractversion	libtesseract version, support 4 and 5 (default: 4) (ignored on Windows platform)
--libleptname	leptonica library name, usually lept or leptonica, 'lib' prefix is automatically added (default: lept) (ignored on Windows platform)
--libleptversion	leptonica library version (default: 5) (ignored on Windows platform)

Example (Command Line)

dotnet PgsToSrt.dll --input video1.fr.sup --output video1.fr.srt --tesseractlanguage fra
dotnet PgsToSrt.dll --input video1.mkv --output video1.srt --track 4

Example (Docker)

Examime entrypoint.sh for a full list of all available arguments.

docker run -it --rm \
    -v /data:/data \
    -e INPUT=/data/myImageSubtitle.sup \
    -e OUTPUT=/data/myTextSubtitle.srt \
    -e LANGUAGE=eng \
    tentacule/pgstosrt

Hint: The default arguments coming from Dockerfile are INPUT=/input.sup and OUTPUT=/output.srt, so you can easily:

touch output-file.srt  # This needs to be a file, otherwise Docker will just assume it's a directory mount and it will fail.
docker run --it -rm \
    -v source-file.sup:/input.sup \
    -v output-file.srt:/output.srt \
    -e LANGUAGE=eng \
    tentacule/pgstosrt

Dependencies

• Windows : none, tesseract/leptonica libraries are included in the release package.
• Linux : libtesseract5 (sudo apt install libtesseract5 or whatever your distro requires)

Build

To build PgsToSrt.dll execute the following commands in the src/ directory:

dotnet restore
dotnet publish -c Release -o out --framework net6.0
# The file produced is  PgsToSrt/out/PgsToSrt.dll

To build a Docker image for all languages:

make build-all

To build a docker image for a single language:

make build-single LANGUAGE=eng  # or any other Tessaract-available language code

Built With

• LibSE from Subtitle Edit
• Tesseract .net wrapper
• CommandLineParser
• SixLabors ImageSharp