DOM DCPs are not centered on my screen

[carl]

As I understand it you are seeing different results between commercial DCPs and ones you made in DoM. If that's right, I would try making a 24fps DCP in DoM (as a test), as it's quite likely your commercial DCPs are also 24fps.

[IoannisSyrogiannis]

[...]
Ioannis, I had of course hoped for a simple answer. You forgot to switch the x to y! Or something like that. But I am starting to realize that is more complicated since the experts here seems to be as clueless as I am regarding this specific problem.
[...]

What I am trying to relay here, is that the experts here can not know if you have x switched to y, since you haven't already shared with them the position of the switches. Therefore, they are expected to be, not as much, but more clueless than you, since you describe the problem but are either hesitant or not oriented towards sharing more clues.

From what you write, you do have access to movie theater(s), to check the DCPs you make. Test them out. If they work, then you know for a fact that the combination runs into issues.
The DSV J2 is some hardware that was withdrawn from sales since mid-2015 and reached end of support mid-2016. That was about two years after Dolby bought Doremi, in case you remember (March 2014, was it?). At that time, Interop DCPs were ruling and SMPTE DCPs were nowhere to be found. That tells you that compatibility with 25fps SMPTE DCPs is an unsafe bet with that machine, the software of which is not up to date.
If you are talking about 25fps (which pushes you towards SMPTE), then it might have been a good idea to try MPEG Interop DCPs (DCP-o-matic added that ability on beta) and instead of 1998 go to 1920 horizontal.
Yet, I don't know, are you planning to screen encrypted content on that setup? I am afraid that you will be able to do so.
If not, why not investing on something that will play out -say- ProRes files? For automation? For interoperability of the SPLs?
If yes, you will probably need something else to use as a player.

From the manual:
The DSV-J2 supports playback in High Definition (1920x1080), 2K (2048x1080) and optional 4K(4096x2160). 3D playback is supported in HD and 2K resolutions only. Super widescreen playback (Stereoscopic) is achieved by sending a unique SDI stream to each of two projectors. The unit features a dual-link HD-SDI output capable of 12-bit 4:4:4 2048x1080p24 or 10-bit 4:2:2 for 48fps and 3D applications.
[...]
The DSV-J2 is also capable of playing MPEG2 Interop movies, pre-show, and alternative content playback.
(For 4K, there was a media block processor from Doremi, MB-4K that would output 8 HD-SDI or 4 DVI connectors.)

[JonasBFF]

I will certainly try with 24fps! But it seems a bit odd that it would result in that kind of output, does it not?

I do not have access to any cinema until the festival starts, and then it's too late if I discover that my DCPs are broken. I know that both hardware and software are old but like I said, we are a small short film festival with a very tight budget. We have up until now screened MP4 and Prores but i figured that we would be able to do DCP when I got my hands on the DSV for free. But perhaps no such luck. I am not trying to withold any info, I am just not sure what info is relevant and try my best to share!

[Carsten]

in 12 years I never had issues with DCP-o-matic DCPs where the image was not centered on the cinema projector when it showed centered in DCP-o-matic main or player. I think it is basically impossible for DCP-o-matic to shift content horizontally. Even if you use horizontal asymmetrical cropping, DCP-o-matic will always center. And even if somehow it could happen, DCP-o-matic would certainly show it in the player. Any visual horizontal offset would have to be baked into the source.
So at least that may give you some confidence. There is certainly something strange with your monitoring setup.

- Carsten