My wife and I each have a MacBook Pro. I have an iPad 1 and she has an iPod Touch 4. I've manually been keeping our iTunes in sync with Home Sharing, dragging newly ripped media from my library to hers on her computer.
Our new Synology has a "home" directory for each of us and two shared folders. One is named "shared" (lowercase "s" to distinguish it from the similar folder on the Macs) where the Local Group "users" has R/W permission and the other is named "Time_Machine" where only a user named "tm_user" has R/W permission. tm_user has a 4000 GB quota, so about half the DS goes to that.
On each of the Macs, I set Finder to show networked drives on the desktop. In the left pane of a Finder window, we have a resource with the name of the DS and a resource with the name of the DS followed by (Time Machine). I open the one with the name of the DS and there are two volumes, "home" and "shared". Double-clicking on each one mounts it, and it shows up on the desktop (as does Time Machine when it's backing up). Then, opening System Preferences, Users and Groups, I dragged the "home" and "shared" icons from the desktop to the user's Login Items, so these mount each time at login.
For iTunes, I created a folder named "Music" in "shared," and then created a folder named "iTunes" inside "Music." I copied my "iTunes Media" folder to the iTunes folder on the DS and then pointed my iTunes to it in Preferences->Advanced. As with any bulk move of data I moved to the DS, I did this using two Finder windows (which would be Windows Explorer on the PC) and used a wired connection. FWIW, I use File Station on the DS as little as possible for data moves between the DS and clients.
On the DS, in Control Panel -> Media Indexing Service, I added the following to be indexed:
Music -> /volume1/shared/Music/iTunes/iTunes Media/Music, checking only Music to be indexed
TV Shows -> /volume1/shared/Music/iTunes/iTunes Media/TV Shows, checking only Video to be indexed
Movies -> /volume1/shared/Music/iTunes/iTunes Media/Movies, checking only Video to be indexed
Audio Station picked up everything. The first thing I noticed was a ton of songs were missing cover art that showed up in iTunes. That's because iTunes doesn't store art it downloads embedded in the songs, where Audio Station expects to find it. iTunes uses a separate database.
Back in iTunes, I filtered each album to show the songs on it, then right-clicked on the cover art shown and selected "Copy", then right-clicked on the cover art for song 1 and selected "Paste." This takes a bit of time and the cover art will flash once it's copied to song #1. Then I selected the rest of the song and right-clicked on the cover art, selecting paste. This can take even more time. If I tried to paste the cover art into all songs at once, often several would be skipped. Doing song 1 separately prevents this. As you do this and go back and look at the album in Audio Station, you'll see it picking up the cover art.
There are some other things to be done to the songs in the album in iTunes. In fact, they probably should've been done years ago, before Audio Station. First, the album title in multi-disk sets often show (Disk 1) and so on for each disk. I used Get Info to remove this from the album titles on each disk so there's only one album name for all disks. Before you do this, activate the disk number column and make sure there's Disk X of Y for the songs on each disk. You can fix this in Get Info if it's missing.
The other thing to be done is where the entry for Artist is not the same on every song is to highlight all the songs in the album and make sure "Part of a compilation" is Yes in Get Info for all of them. Otherwise, you'll wind up with a separate album listing for each artist.
Finally, as I went through doing this, I fixed the Genre in Get Info where iTunes had got it wrong. When the Genre field is blank, you can use the down arrow to see all the Genre's iTunes has, but you can create your own here.
We have an impeccable collection of music and cover art in Audio Station. I've intentionally left the cover art off singles to distinguish them as not being an album. One could also have the cover art and distinguish them by adding (Single) to the song title(s) in iTunes Get Info.
My wife and I now use Audio Station on the Macs and DSaudio on the iOS devices for playback. In our opinions it is much nicer and more intuitive than iTunes. We have an AirPort Express with speakers at each end of the house and can control the music they're playing individually with either the Macs or the iOS devices.
I periodically copy the other files in my Mac's iTunes folder (besides iTunes Media) to the shared/Music/iTunes folder on the DS. Immediately after doing so, I could start iTunes with the option/alt key held down and point iTunes to use everything from the DS, not just the iTunes Media folder. The reason I don't is because I sync my iPad with my Mac (wirelessly) and it goes faster with all the Apps and Books I have, even though they too are on the DS. Although my wife no longer uses iTunes, she also syncs her iPod Touch with her MBP (usually wired since she also charges it that way).
Our TV Shows are El Gato eyeTV recordings converted to m4v and placed in iTunes TV Shows.
Our Movies are typically Handbraked DVD main features as m4v in iTunes Movies.
None of our videos are protected files from the iTunes Store. It goes without saying, these can only be played with Apple software.
We typically open them with File->Open in VLC, pointed to the mounted "share" volume, but with them in iTunes, I could run that on my Mac and use iTunes to serve the iOS devices, particular an Apple TV, which we don't have. Or we could mirror from the iOS devices (streaming from my Mac, which is getting them from the DS) to an Apple TV.
Instructional or other DVDs where we want to keep the chapters and extra features are ripped with RipIt and located shared/Movies/DVDs on the DS. I've created an alias to shared/Movies/DVDs on our desktops. DVDs open with the Mac's DVD Player application.
I hope this helps. We found Synology's "iTunes Server" to be pretty worthless, but that's Apple's fault, not Synology's. Questions are welcome.
DS 1512+ w/3GB, 5 x 3TB Seagate ST3000DM001 8.2TB RAID 6, half files/half Time Machine.
Icy Dock MB559U3S-1SB enclosure w/4TB Hitachi UltraStar via USB 3 for files backup
UVERSE to AirPort Extreme + 2 AirPort Express w/speakers. TRENDnet TV-IP312WN camera
CyberPower CP1500PFCLCD Sine Wave UPS
DSM 4.1-2661 w/SSH + SFTP, VPN Server, Syslog Server, Media Server, Mail Server, Mail Station,
Audio Station, Surveillance Station, Photo Station, Web Station - DS Apps on iPad & iPod Touch.