Yeah the stretch should be saved in the cfg, but unfortunately the Quadric Distortion Amount or Scanline settings won’t save. I really wish Mame would update so it had more features. It’s pretty buggy and it won’t save most of the tab settings.
Is there any way I can implore you all to experiment with these in mame2003-plus? 
We are in active development with several coders. In general the spirit of the work is oriented towards closer and closer integration with libretro/RetroArch. If and when there are problems using overlays with the core, I and possibly other coders are available to work though them.
I hope that eventually other MAME cores will have an opportunity to get tightly integrated with the libretro API and in truth I am hoping that mame2003-plus serves as a proof-of-concept. It would be great to have awesome integration with bezel overlays as part of that proof.
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@Kondorito nope, I tried a few things more lately, but ultimately I just measure the positions using Photoshop. I would be very interested if you ever manage to progress more in this matter.
@markwkidd I don’t understand if you want us to try the MAME or the Libretro overlays?
Thanks @cosmo0.
Hey @Orionsangel, I just realized something.
All the horizontal lay files (at least all the ones I checked), have the same exact coordinates (pasted below), even though the pngs are specific and different for each game in terms of spacing and transparent area.
For bezel:
<bounds x="0" y="0" width="1280" height="720" />
For game screen:
<bounds x="232" y="54" width="816" height="612" />
Sorry, but I feel like either I am slow on the head, or missing a configuration/step. Is there another place in which the artwork takes the coordinates rather than the lay files, or do we need to do manual stretching for each game? Stretching will kill the perfect aspect ratio and accuracy for each game, so I don’t know about it.
Any insight will be highly appreciated 
@cosmo0 Mark is wanting people to test the new mame2003-plus core.
I think setting up bezels within that core and giving feedback about issues is his goal here.
Exactly! 
People are reporting here in this thread that other MAME cores aren’t saving their settings and it is causing problems with bezels. For example this “stretch” issue.
I don’t think there are stretch or other issues with mame2003-plus and bezels but if there are I would like to know about it and be able to help with a fix!
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I would suggest getting a thread going for the new core. Github doesnt generate testers imo only developer types.
Even if it just points to the relevant github stuff…I guess there is one on RetroPie
That’s valuable input @Thatman84. I’ve been focusing on the RetroPie forum but I should start a thread here.
We’re stewing on a few more changes to the input system so I may wait a couple of days in the dream that we will have a “final” input system to share with the libretro forums. I have been building up some docs at least!
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The more I read this thread looking for bezels to try with mame2003-plus the more confused I get. The thread is confusing to me because it seems like most of the posters are actually not trying to port MAME bezels/overlays to RetroArch/libretro.
Folks other than @cosmo0 seem to be mostly trying to use native MAME artwork functions within libretro MAME cores – which is doomed to not work well. I say this from some experience.
In other words, one clue that things are not going to work well in RetroArch with an arcade bezel is if the process of using it involves changing any settings at all in the MAME UI. That, as a general approach, is not going to work for libretro MAME cores even though it might be possible to sometimes “make it work” for individual games after you do some tweaking.
I also have noticed that most LAY files have the same coordinates. I’m pretty sure you have to use the stretch values to position the screen correctly.
However, I notice that there are several things in the LAY file that I never tried to use. For instance:
<view name="Cab Artwork">
<screen index="0">
<bounds x="555" y="0" width="810" height="1080" />
</screen>
<overlay element="screen_mask">
<bounds x="554" y="0" width="812" height="1080" />
</overlay>
<backdrop element="screen_bezel">
<bounds x="518" y="0" width="884" height="1080" />
</backdrop>
<bezel element="bezel">
<bounds x="0" y="0" width="1920" height="1080" />
</bezel>
</view>
Maybe there is a relationship between the screen, the overlay, the backdrop, and the bezel, to calculate the final screen coordinates… ?
Or maybe we need to add or substract some x and width values before multiplying them by the stretch values…
It’s all very confusing 
About the ratio: I used to want every game to have a pixel-perfect aspect ratio, but I changed my mind lately, when I found out that many arcade games, Street Fighter 2 being the most prominent, did not have the correct aspect ratio if you’re using pixel-perfect output, and relied on stretching on a CRT to display the game correctly.
So, personally, I don’t care much about pixel perfection and aspect ratio anymore, as it’s just too complicated and annoying.
Yeah but this thread is about converting MAME bezels to Libretro overlays, so I wondered if it was about testing MAME bezels or Libretro overlays in mame2003-plus But apparently according to @markwkidd latest message it would only be Libretro overlays.
I will just say I don’t have any troube with Libretro overlays in MAME 2003 on Retropie. I pre-configure them, though, I never change anything in the menus.
Me and @Kondorito.
It seems I wasn’t very clear in my initial question. I’m just trying to convert MAME lay files coordinates into Libretro CFG coordinates 
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Its all clear now!
I have not touched bezels of overlays recently but this if figured out would be great
Once I get all my systems and games sorted (waiting on buying a NAS and finishing my house) i will finally be able to focus soley on bezel artworks which will be sweet!
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After 3 years (lol) I got back to the subject, and I finally understood.
For anyone interested, I documented my findings here: retropie-overlays-arcade-realistic/DEVELOPMENT.md at master · cosmo0/retropie-overlays-arcade-realistic (github.com)
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