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
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In fairness to him, he offers the posters an opportunity to propose a technical solution and responds to all the posts that do it. It is interesting that nobody in the thread went to check in the code of mpv, smplayer, etc. to see how it's done there. Surely this would be the best response to his request for technical suggestions?
Maybe because these users just can't code?