Mpv – A free, open-source, and cross-platform media player

I use it to inspect video frames by frames, particularly being able to go back one frame. VLC doesn't support it, this thread about the feature is hilarious https://forum.videolan.org/viewtopic.php?t=120627

The developer responds to a comment:

But many players are able to do it for years.

with:

If it's so easy, why are you not doing it?

He's not just a butthole, he's a stereotypical open source developer butthole. On the other hand, if he worked for Microsoft, he'd be claiming that it takes a PhD to do it...

The dev said they are happy to accept patch for this feature. Remember that you're not entitled to demand new features, as a (non-paying) user, you can't allocate dev's time to work on what you want.