u/Boomob

Cool tool I found, it works like Yomitan for browser but for the MPV video player
https://github.com/ksyasuda/SubMiner

MPV Skin Wrappers:
https://github.com/Samillion/ModernZ - The skin shown in the video
https://github.com/cyl0/ModernX/
https://github.com/tomasklaen/uosc - Most clean UI functionally to me

How to enable color coded and underlined subtitles for Frequency and JLPT Level:
In C:\Users\{username}\AppData\Roaming\SubMiner\config.jsonc
Changing the settings:
"enableJlpt" to true on line 272
&
"frequencyDictionary": {"enabled": to true on line 302