[jjd-uk]

1) Convert Movie Version. I might be missing something but I don't understand the naming of this item. From what I can see, this is actually *creating* a movie version out of the selected movie. What is it supposed to be converting? But see the following points, because I think we could and should do without this entry.

It's converting it from a seperate library item to a version of an exisitng library item.

2) Selecting "Manage Movie Version" on a movie that does not have versions leads to unexpected behavior from the following window, that I see has been already touched upon. The selected movie is represented as Standard Version and you have "Add version" on the right of the dialog window. But if you use that, you go to a file requester, where you can browse through your file structure. If that's considered useful for extras, fine, I sort of get that. But then it should be limited to Extras, not movie versions. Selecting "Add version" and not getting a list of movies in the library is really counterintuitive (at least for me, but I don't think it's just me, otherwise I wouldn't be pointing this out).

The add version button is for adding another movie version, there is a separate add extras button for those.

I agree with you that the addition of movies versions needs to be better handled, this point has annoyed me also. For example I have theatrical version of Justice League 2017 and in addition I have Zack Snyder's Justice League 2021 so the Zack Synder version isn't detected as the same movie as theatrical version, that means I have to navigate through the file browser to the folder containing it to add it as a version. Perhaps there could be some shortcut like there is with artwork where there's an item folder entry, since in my case both versions are in the folder.

However I'm unsure if we should be presenting the full list of movies in the library as that could be quite long.

3) Performance. When using "Convert Movie Version", which actually "creates" a movie version out of the selected movie, I get ten seconds of Kodi "thinking", where everything is stuck. This on a Ryzen 5 3600. I dread how performance could be on an Amlogic or Pi machine (it might border on unusable for big libraries). And I'm talking about a machine that basically never makes me wait for anything, with database sitting on a fast NVME SSD drive. I remain optimistic about optimization being possible here. Kodi lists 3109 items for me in the "Convert into an additional version of movie" if that matters. And those ten seconds of waiting happen for each and every movie I decide to operate on. At a minimum (if possible, I don't know), the query that takes 10 seconds to produce results should be cached. Otherwise...say one has 300 movies to create versions for... it's 50 minutes of waiting. A bit excessive...

It was noticed that perfomance was degraded when you open the movie library views, so there is a PR open looking to address that. Not sure if that could also improve this.

4) Linked to #1 and to the end of #3. The dialog states "Convert into an additional version of a movie", while it is instead creating the first version of a movie. And, as far as I can see, there is no other way to create the first version of a movie.
The problem is that when you select this you are actually not operating on the movie you have selected. Or you are but in a backward way.

My understanding from my testing is as follows:

movie abc version 1.mkv - this gets automatically added to library
movie abc version 2.mkv - scan detects this as a new version so asks if you what to convert it to a new version of movie abc version 1

If you say no to the convert then you end up with duplicate library entries for movie abc one for each of version 1 and version 2.

If you say yes to the convert then you have a single libray entry for movie abc and you access the versions either via the dialog or directly from library if in display as folder mode.