Screen capture black frame single images.

[Innomen]

This might not even be the correct forum for this but I am wanting to capture stills from a movie with subtitles I have added and this means getting around that blasted black screen result.

I know apps like kmplayer and vlc have screen capture natively but the app I am using skips right to the subtitle and pauses making it super easy for me to grab them all, if only they would work. Greenshot and Faststone both fail. I end up with a black rectangle.

The app I am attempting to capture from is "Subtitle Edit 3.2.8"

Thanks for your time.