Cannot get smooth scrolling in 1440p

Insert Disk Two
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Cannot get smooth scrolling in 1440p

Unread post by Insert Disk Two »

So before I explain my issue:

- I have my MiSTer hooked up to a gaming 1440p monitor with VRR.
- I am using 1920*1440 resolution in 4:3
- I have 0 issues with any other cores including PAL cores like C64
- I have AGS correctly setup

The issue:

When playing games in 1920*1440 resolution scrolling is a mess. Both in 50hz or 60hz (not that it should do any difference since I am using VRR).
When playing games without altering any settings in 1080p, scrolling is perfect.

I tried also vsync 0/1/2

This is my line to achieve 1920*1440@50hz (works perfectly with C64):

video_mode_pal=1920,32,32,50,1440,4,5,26,150000

Any help would be appreciated as this is very frustrating. Thank you!
Insert Disk Two
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Re: Cannot get smooth scrolling in 1440p

Unread post by Insert Disk Two »

Ok, solved. I created this line mode. Putting here maybe other folks may find it useful.

[minimig]
video_mode_pal=1920,128,208,336,1440,1,3,36,186050
Malor
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Re: Cannot get smooth scrolling in 1440p

Unread post by Malor »

I'm using vsync_adjust=2, plus the lines:

Code: Select all

[Minimig]
video_mode=12
down at the bottom, which sets 1920x1440x60Hz for the Minimig core. This mode drops to 50Hz with no trouble.

I just spent about a half hour messing around with various games, and everything looks right to me. Hybris was the first one I tested, and it seems about like I remember, although my reflexes sure don't.

AFAIK you shouldn't set video_mode_ntsc and video_mode_pal unless you absolutely must. It's better to set NTSC frequencies by default, as I understand it, because it gives the scaler more bandwidth and timings to use, so you'll in general get better results, even when displaying PAL modes.
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Re: Cannot get smooth scrolling in 1440p

Unread post by Insert Disk Two »

Ah, I will try that. Thanks!
And yes, I'm on VSYNC=2 always :)
Optiroc
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Re: Cannot get smooth scrolling in 1440p

Unread post by Optiroc »

With my LG OLED C7 I need to set ntsc/pal modes to get smooth frame pacing.
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Re: Cannot get smooth scrolling in 1440p

Unread post by Insert Disk Two »

Hmmm... I don't understand why separate PAL and NTSC frequencies are required. Probably there is a reason :)
Malor
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Re: Cannot get smooth scrolling in 1440p

Unread post by Malor »

It's probably for monitors that can't accept anything but 50Hz or 60Hz. In those cases, you may need to specify a specific NTSC or PAL resolution.

If the display can handle either, apparently it's better to start with the 60Hz signal, because it can easily decrease video bandwidth by slowing the refresh rate, while it's probably not allowed to increase it. I think it would have to trade away resolution or do weird timing tricks (like skipping the vblank interval, which is how they got 1920x1200 down a single-link DVI cable) to speed up from 50Hz to 60.

That is a guess, however, not real knowledge.
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Re: Cannot get smooth scrolling in 1440p

Unread post by limi »

Optiroc wrote: Tue Nov 29, 2022 7:29 pm With my LG OLED C7 I need to set ntsc/pal modes to get smooth frame pacing.
This is the solution. I had this issue until I explicitly set both, even though the current MiSTer recommendation is to only set one. Core bug or framework bug.
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