subtitle-overlap-fixer

Corrects issues with SRT subtitle files that have been converted from more complex WebVTT format subtitles

Stolen from @nimatrueway's Gist (https://gist.github.com/nimatrueway/4589700f49c691e5413c5b2df4d02f4f) and slightly enhanced for my needs (mostly by adding the functionality to combine lines with overlapping timecodes)

Problem

Converting WebVTT subtitles to SRT subtitles via ffmpeg like so: ffmpeg -i yourvttsub.vtt outputsrt.srt mostly works, but since WebVTT supports many more timing and layout options than SRT, and ffmpeg's WebVTT implementation does not comply with the spec, you can end up with a SRT that has a ton of incorrect overlapping timings and lines.

This tiny program attemps to fix those issues.

What it do

• Removes empty subtitles
• Combines subtitles if the end-time of the previous subtitle overlaps with the start-time of the current subtitle.
• Removes subtitles with very very short duration (<150ms) if they contain what the previous line contains
• Removes first line of a subtitle, if it is the same as the last line of previous subtitle

Installation/Usage

1. You need a recent version of go
2. Clone repo, cd to repo folder, run go build
3. This will create an executable named subtitle-overlap-fixer
4. Run that executable on the SRT file that ffmpeg spit out (via ffmpeg -i test.vtt test.srt) subtitle-overlap-fixer test.srt
5. This will back up the original .srt with a .bak extension, and generate a cleaned SRT file

NOTE: No warranty, express or implied. This works for my specific use-case perfectly, and I couldn't find a better way to solve it.