Top 5 subtitles-parsing open source projects

Go library and command-line tools for manipulating .srt, .vtt and .ssa subtitles

Project Nephos [GSoC '18]: Automated recording, processing, and uploading of TV streams for Universities.

A Python library for editing subtitle files

Very basic Node.js/JavaScript library to generate VTT open subtitles files

convert TTML subtitles to SRT subtitles