Mine is Local Send which is a FOSS alternative similar to air drop that works across a variety of devices.
Are there any FOSS apps that can do this? MPV can move frame by frame but moving back is so unusably slow.
OpenShot. But that’s a video editor and not a conventional video player per se.
Depends on the machine and… maybe other things. I used to think that, too, but on my current machines I can step backwards just fine.
It’s probably a much more intensive operation requiring processing a lot of the file from before and throwing away current buffers or something.