From Disc to Drive: A Beginner's Guide to Preparing Your Media for Jellyfin

[Perseverant]

On a blu-ray Into Great Silence disk 2, there is a special feature called "gallery" which looks like just some still shots(probably JPG or png)
I can see how to extract those for viewing. Any advice?

Late reply, I know, but hope this helps:
I can't speak to your specific circumstance, but I can tell you I've run into a lot of galleries over the years and they're almost always a bit odd.  They're being stored in some way where they play fine on the disc using your remote to advance, but when they're ripped with MakeMKV, they'll often play at an insane rate, or the first few images will display slowly, then you'll hit the end of the file and 100 images will zip by at an incredible pace.

Sometimes, the galleries are just not salvageable, but I've often had success by throwing the gallery clip into MKVtoolnix, going to the "Default duration/FPS" box, and entering "0.25" without the quotes.  This will set the framerate to 0.25 seconds, which, for most of these way-too-fast galleries tends to display each image for 3-5 seconds.  Note that you should change the framerate AFTER encoding into your final video format.  So, you might want to re-encode it from x264 to x265, then use MKVtoolnix to alter the FPS of the x265 file (the correct way).  If you altered the FPS, then re-encoded the 0.25FPS file from x264 to x265, it will likely break the clip.