This program adds a subtitle file to a movie. Note that this can only be done once to a movie (the second time would override the first).
Copy and paste this command to download this repository after you've changed directories to the folder you want.
git clone https://github.com/hussein-esmail7/ffmpeg_subtitle
Then change directories into that folder.
cd ffmpeg_subtitle
After that is done, you can now run the subtitle program.
python3 sub.py