MiSTer FPGA Forum

Posted: **Mon Apr 26, 2021 7:02 pm**

I am struggling to understand exactly what this does, and what the optimal setting is. I've looked at the readme and had a play around, but it doesn't quite make sense.

I have a 1920x1080 monitor and I want a PAL setup with 4x vertical scale.

I have the following in mister.ini
vscale_mode=0
video_mode=8
vsync_adjust=2

In the Minimig core menu I set Scaling to V-Integer.

By default the core reports a resolution of 1508x286 (on the standard 1.3 disk prompt or a clean 3.1 wb install). This means that it scales 3x. From trial and error, I have found that 'Adjust screen position' allows me to reduce the vertical height to 270 so it scales 4x on my display. I press the 'up' cursor a few times and when it hits 1508x270 the scaling flips to 4x.

I have a few questions about this:
- Where does the initial height of 286 come from? What meaning does this have? Why is it not 256?
- Is it sufficient to adjust the height to 270 in one direction? Should I also be adjusting the 'bottom right' with the ALT key by an equal amount? I don't quite understand the difference.
- Why is the width 1508?
- Do I also need to adjust the width to maintain the correct aspect ratio or is this scaled automatically?

Sorry if this is all really obvious stuff and I'm over-complicating. I'm just keen to have an optimal setup.

Posted: **Thu Apr 29, 2021 2:45 pm**

Not sure about the other things but 286 pixels probably includes the overscan area. In Workbench you can actually increase your workspace to take full advantage of that extra bit of resolution.

Posted: **Sun May 02, 2021 11:11 am**

The display is so wide because of the super high-res screen modes of the Amiga and it's ability to scroll low-res screens at super high-res resolutions.

Posted: **Mon May 17, 2021 9:13 pm**

I am having a slight issue with my CRT PVM over RGB. Games like Lemmings, in 320, are shifted slightly to the right.

Posted: **Tue May 18, 2021 4:33 am**

One of the core menu options is pixel clock, 22mhz? or variable. Having it set to the fixed number forces that wide resolution at all times.

Games shifted to the right was also real common on real Amiga hardware because it gave access to some extra sprites. If you play with analog out/no scaler you just got to deal right now.

Posted: **Sat Jun 24, 2023 12:07 pm**

FoxbatStargazer wrote: ↑Tue May 18, 2021 4:33 am
One of the core menu options is pixel clock, 22mhz? or variable. Having it set to the fixed number forces that wide resolution at all times.

Games shifted to the right was also real common on real Amiga hardware because it gave access to some extra sprites. If you play with analog out/no scaler you just got to deal right now.

Is there no way to adjust H and V positions using the MiSTer Amiga core? I notice that such options seem to be present in most arcade cores.

Posted: **Sat Jun 24, 2023 1:43 pm**

For MegaAGS I have created a tool that generates vadjust files on the fly, with parameters for v/h shift and scale (4, 5 or 6x).

Source is available here, and I’ll try to attach a prebuilt AmigaOS binary. (I failed with the latter on the phone, but it’s available here.)

Posted: **Sat Jun 24, 2023 5:21 pm**

So it is already part of AmigaVision? I was just about to install AmigaVision onto my MiSTer.

Posted: **Sat Jun 24, 2023 10:53 pm**

wmd wrote: ↑Sat Jun 24, 2023 5:21 pm
So it is already part of AmigaVision? I was just about to install AmigaVision onto my MiSTer.

Yep

Posted: **Sat Jun 24, 2023 11:04 pm**

That's great. Without wanting to sound like a complete idiot, how do I adjust those settings, and can it be done on a per-game basis?

Posted: **Mon Jun 26, 2023 2:29 am**

For clarity? As I understand these settings only adjust the position for HDMI output, not the analog output. Its not like Jotego's CRT V/H stuff.

Posted: **Mon Jun 26, 2023 11:28 am**

FoxbatStargazer wrote: ↑Mon Jun 26, 2023 2:29 am
For clarity? As I understand these settings only adjust the position for HDMI output, not the analog output. Its not like Jotego's CRT V/H stuff.

Indeed, the “adjust screen position” feature only affects the video scaler output.

Posted: **Sun Jul 02, 2023 1:17 pm**

Any chance this feature could be added to analogue output at some point?

MiSTer FPGA Forum

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