Keyframe Extraction Length

[JazoBurbs]

Question on Keyframe extraction...
When I setup my libraries I executed this task and it took quite a while (hours). However, I needed to delete one of my libraries (largest one). When I went to run Keyframe Extraction again, it only took about 30 minutes. Why would it take far shorter this time around? Could it be that it still stored this data from the previous library? Is there risk of this data not matching up with the newly created library? To clarify, the newly created library contains the exact same media as the one I created previously.

Would be good to be educated on how this works.
Thanks!

[TheDreadPirate]

It depends on whether you had other tasks going on when you initially ran the keyframe extractor.

But it's also possible Jellyfin retained some metadata. It doesn't immediately clean up after you remove content.

[JazoBurbs]

Got it. I checked the folder size and it still is pretty substancial (500MB). Not sure if it should be bigger? In terms of other tasks, I would say that both times it ran Trickplay was also running. If JellyFin retained some of these data, how does it connect to the new media? Does it match via file path? MovieDB ID #? Is here a way to clear this out and regenerate Keyframes only without deleting the library again?

[TheDreadPirate]

When you rescan, if you select "replace all metadata" or "Search for missing metadata" and check "replace all images" that should also regenerate keyframe images and trickplays.

I have no idea how Jellyfin would rematch already existing data with re-added content. Maybe TMDB IDs, maybe a hash or something. IDK. I'm not an expert in the code. I just know from using and testing Jellyfin that things like watch status are retained when I've recreated libraries. So I'm assuming other data could potentially be re-matched with re-added content.

[JazoBurbs]

Thanks. I noticed that Collections remained as well to your point about watch status. This is helpful. Hopefully “replacing all images” isn’t needed as I don’t want to delete Trickplay. This was new to me as I thought “replacing all images” was just images downloaded for metadata not, quite literally, all images associated with the library/selected media (ie. Including Trickplay).