To be precise, it only works with MSP OSD / Displayport.
It saves srt subtitle file and osd file, along with the video. You will also need a font file to overlay on a video. Make sure to get the right font file for your FC firmware.
Use this free tool to overlay the subtitles.
https://github.com/avsaase/walksnail-osd-tool/releases/tag/v0.3.0
or this
https://sites.google.com/view/sneaky-fpv
More info about RubyFPV: https://rubyfpv.com/
Happy flying!
