MiSTer FPGA Forum

Hey guys.
I tried to look after any hints here and there to solve this problem.
It’s strange let me explain.
I have a Crt Phillips Matchline Tv 29´ and when I launch Arcade cores I have on 99% of the games a display issue.
Most of the time the game takes more than the screen surface and is not centered. I manage to get something somewhat ok with H/V adjustments (most of the time I have to got max-8 horizontally)

But I have no problems with consoles cores, the display is on point.

Any Ideas ? Is there a way to add some code in order to impact arcade cores only or it's a bad idea ? Thanks for your help.

This also happens to me quite a lot in arcade cores in my CRT, there's several overscan, and even moving the screen with H/V adjustments only solves what part of the screen I want to miss. The irem m92 new one (your last screenshot) is a good example, in R-Type Leo I either miss the top of the screen, or the score in the bottom, I can't have both.

If your CRT has a service menu, you can adjust the geometry of it, but it's very hard to find a setting good for everything, you need to find some middle ground.

This is not a problem, but an expected result for running FPGA cores with consumer TVs. The cores are developed by analysing the original hardware and try to stay as close to the original system timings as possible.

As home consoles were built with consumer TVs in mind, the analog output of the FPGA cores usually works fine with consumer TVs from the same region (PAL cores with PAL TVs (50Hz signal) and NTSC cores with NTSC TVs (60Hz signal) and many consumer TVs will display both 50Hz and 60Hz signals properly.

Arcade hardware was never intended to be used with consumer TVs, and correspondingly the cores will output varying analog signals. CRTs used in arcade cabinets can sync with a broader range of signals and can be adjusted to make the image fit the viewable area.

If you want to play different arcade cores on a consumer TV, your options are limited: Like mentioned in the comment above, you could try to adjust the image of your TV using the service menu. Usually this means to reduce the vertical and horizontal size to get less overscan in some cores, which will result in black borders in others. Some core authors offer different timings to help with compatibility, and you should test if they help in your specific case. Example: the R-Type core offers the original 55Hz and optional 50Hz and 60Hz timings. Please note that these options often change not only the output, but the timings of the core itself, resulting in slowdown or speedup.

You could also experiment with using custom video modes and the vga_scaler option in the MiSTer.ini configuration file. This basically fixes the output timings to create a stable picture (without overscan) on your TV and scales the core output to that video mode. It can be a time-consuming process and depending on the core resolution/modeline combination scaling artifacts can be visible. In conjunction with vsync_adjust=0 it even allows to run the display at a different refresh rate than the core output (which will also have visible artifacts like unsmooth scrolling). For finicky TVs, it is the only way to get any visible output at all with some of the arcade cores.

Please note that these limitations of analog output and CRTs are one of the reasons the MiSTer project exists. It comes with a powerful built-in scaler that can convert all these weird arcade signals to a high-resolution digital HDMI output. Scaling is highly customizable and comes with a huge selection of filters and masks to adjust the image to your liking.

Thanks a lot for your anwers !
I was expecting that since I don't have issues with console games.
The only thing I'm worried about is, if I do modify vga scaler in the ini (I already tried but got weird results) is it gonna affect also consoles display ? I guess yes, I haven't tested and I should have but I was focued on arcade cores only.
Unfortunately I have a Matchline Philips 29PT9021/19 model and I tried everything I could ever imagine to access to the service menu but I couldn't, I've tried all the 062596 etc codes and I think I have to open the tv and do it manually but I don't want to screw everything up. Usually I prefer to access with remote and take a picture of the parameters in order to come back to default settings if I ever make a mistake.

Anyway thanks for these infos, I will play like that on my TV and try on a real arcade cab soon.

If I remember well, some cores (maybe the Jotego ones like CPS2), have an option to crop the picture vertically or horizontally in a CRT, that also helps with this.

Getting arcade resolutions to play nice with CRTs can be a very deep rabbit hole. I gave up chasing a "perfect" image long time ago, it's simply impossible if you want to display many different sources on one set. It's best to just accept this, especially seeing as most of the time game designers knew about these problems and followed the principle of "safe area". This applies even to arcade monitors, since despite their greater adjustment flexibility many operators wouldn't bother tweaking the image, sometimes they'd be put in different cabs, and so on. You can check this vid of original AvP cab, which is not that much better than your pic.

Definitely don't bother with adjusting stuff insides of your TV, because a) it's dangerous b) it will break other games display.

And if you really can't live with the way MiSTer's arcade cores are displayed on a CRT, look into Groovymame and crtemudriver solutions - they're a bit more flexible and can adjust resolutions automatically (though the setup is not for the faint of heart.)

lixir wrote: ↑Fri Apr 21, 2023 10:14 am

The only thing I'm worried about is, if I do modify vga scaler in the ini (I already tried but got weird results) is it gonna affect also consoles display ? I guess yes, I haven't tested and I should have but I was focued on arcade cores only.

The MiSTer.ini file has the option to use different settings for each individual core. You would need to edit the file manually, this cannot be done with the settings menu. You could start experimenting with a single arcade core, and this would not interfere with the others.