Images to PGS SUP subtitle

PGS SUP subtitle generator (Image sequences)

It generates subtitles starting from a series of white-background black-content images (png/jpg format)

A real case where it can be useful is when extracting images of hardsub subtitles using VideoSubFinder: these images often contain text easily recognizable by a human but not always correctly identified by Tesseract. In this case, it can be helpful to reduce the space occupied by the sequence of images while still making them usable in a video by converting them into a PGS subtitle file

Each image must have the name in the format HH_mm_ss_SSS__HH_mm_ss_SSS_XXXXX.extension, where:

• the first HH_mm_ss_SSS is the start time
• the last HH_mm_ss_SSS is the end time
• XXXXX is the sequence number

A script to correct times and durations of generated subtitles is also included in the project.

FAQ

Why not simply use an OCR to generate an SRT file?

• You don't always have to deal with well defined images
• You don't always have to deal with images containing text

When you can, prefer subtitles in text format (like SRT)

If you don't want to use an OCR, why is there a "tesseract" option?

If you have a list of images and not all of them include texts, you may want to filter those in which tesseract manages to recognize at least one character of the alphabet
In this way, it is possible to exclude images that do not contain any text at all and, at the same time, not rely 100% on the entire Tesseract output

How are the images coded inside the PGS SUP file?

Refer to "Method for run-length encoding of a bitmap data stream", you can also find a summary in the /docs folder of the project

Usage

usage: pgs_sup_generator.py [-h] [-p PATH] [-wi WIDTH] [-he HEIGHT] [-o OUTFILE] [-t TESSERACT]

Image directory to PGS SUP file generator.

optional arguments:
  -h, --help            show this help message and exit
  -p PATH, --path PATH  image directory path
  -wi WIDTH, --width WIDTH
                        video width in px
  -he HEIGHT, --height HEIGHT
                        video height in px
  -o OUTFILE, --outfile OUTFILE
                        output filename
  -t TESSERACT, --tesseract TESSERACT
                        tesseract binary path

usage: pgs_sup_retimer.py [-h] [-i INPUT] [-o OUTPUT] [-s SUM] [-m MULTIPLY]

PGS SUP file subtitle timing bulk changer.

optional arguments:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        sup input path
  -o OUTPUT, --output OUTPUT
                        sup output path
  -s SUM, --sum SUM     sum given milliseconds (even negative)
  -m MULTIPLY, --multiply MULTIPLY
                        mupltiply times for given value