[sepedeus]

I have been backing up my DVD and Blu Ray collection and I'd like to be able to watch the backups for example from a NAS server using a Kodi -like software, because it would be convenient.

So far Kodi seems to be the best choice as it has the best support for playing DVD and Blu ray backups.

Only issue is currently that the movie browsing in the library is focused on movies and not on the releases and the physical copies that contain the movies. And I get that, watching the movie is probably the main thing for most and there's a clear design choice made in Kodi to have it like that.

Still, I have found many posts in forums and Reddit where people would like to achieve the same thing that I'm looking for. I'd like to see the release in the top level, I'd like to go inside the release and select the disc I want to play and after that I want the dvd/bluray to handle the movie, subtitles and audio as it is meant in the release. The biggest issues currently are are that I might have several releases of the same movie, a release might contain several versions of the movie and the release can contain extras on a separate disc and I just can't get all that to work in the library currently.

Based on my research a solution might be to write a "plugin source". If I understood correctly with that I might be able to affect the way the movies appear in the menus. Am I on the right path? And I'd also like to be sure that someone with the same issue has not solved this already and if there might be an existing add-on to use.

[NeoCortex]

The upcoming version of Kodi (Omega, currently in Beta) handles versions.  So if you have multiple versions (or I guess different discs would work as well), you can select the top-level title and then select which disc/version you want to load.  If you don't mind trying a development version, the latest nightly builds have it working pretty well at this point.

EDIT: Here's the wiki page to get you started: https://kodi.wiki/view/Video_versions

[sepedeus]

Thanks for the tip. I think that would get me closer to what I'm trying to achieve, but it would still be a workaround and not the optimal solution. 
Could you or someone point me to an example implementation of a "plugin source" https://kodi.wiki/view/Plugin_sources ?
I'd like to try out it but that wiki page seems describe just the overall functionality of a plugin source and I think I would need more detailed documentation and maybe a working example would be a great starting point when I could modify it and see how it behaves.

[NeoCortex]

Writing plugins is a bit out of my league.  So I'll leave that for someone more knowledgeable to chime in.

As far as using the Movie Version feature, I'd think that would handle pretty much entirely what you're trying to do.  The listing as it would appear in the video library would be the Release, and then associate with that whatever separate discs/versions contained in that release you want as other movie versions.  Then you could have a second library listing that would be a different release and have a different selection of discs/versions associated with it.  What is it you're trying to do that is outside that?  Not trying to be difficult at all.  I just figure the more specific you can be in how you see it working, the more helpful the responses will be.