So what I am wondering is how to best play the files on my HTPC. Is it
1) Connecting my HTPC to the library on the server and playing all files over the network from the server (the files are on a NAS, so they play over LAN anyway). That way, I don't have to enable library sync, right? Are there any issues with this? Any files that might not play correctly with seek functionality, for example? Obviously I want to disable all transcoding.
2) Playing on my HTPC from the local library like now, and enabling Library Sync with the server. Is this a better option in any way, except from the possibility to do tagging etc. on the HTPC, which I don't really need?
#1 is the way to go. (re. #2., library sync does not work like that, more later...) Getting back to #1....
In order to do that, you need to set up the direct file access on the HTPC so that the filename paths match those on the server. This depends on how you reference files, for example, on the NAS. If the server is using a mapped drive letter, and references a video file at, say, X:\Videos\Movies\My Movie.mkv, then setup the same mapping on the HTPC. However you do it, the important thing is that the file paths on the server and the HTPC match.
Having done that, go into MC's settings on the HTPC and type
local in the search bar at the bottom. There is only one result. Make sure it's ticked.
Now, if that option is
not enabled, then when your HTPC, connected as a client to the server, requests a file, the server fetches the file and 'serves' it to the HTPC. With the option enabled, if the HTPC can reach the file directly, it does so. This results in better (imo) playback and a lot less work for the server to do. It also means that if the server goes offline in the middle of a movie, the HTPC will continue to play the movie without faltering.
Library sync...
Library sync is a system that allows MC clients, such as your HTPC, to send changes and updates to the library back to the server. Think of things like [Number Plays], [Last Played], [Rating] etc. etc. If library sync is not enabled, changes here will not be reflected in the server library. The HTPC will discard them.
Library sync WILL NOT, and cannot, 'merge' two separate 'local' libraries.
Also, in order for library sync to work, you must set up a username and password (authentication) in the Media Network options on the server, and use these on the HTPC to connect to the server.
Get yourself setup this way and you should find things pretty much rock solid. We've had little to no issues in more than ten years. The only mild frustration can be with library sync and things like [Number Plays] and [Last Played].... Typically, before bed, we watch a movie, the movie ends, we turn off the HTPC and go to bed. As library sync is
not an instaneous thing (it's quick, as in minutes or less, but not instaneous), the playback data has not had time to sync back to the server, and is lost. Other than that, everything else will be golden.
Hopefully that helps, fire away if you still have questions.
-marko