VGA Mode Changing for 720x400 and 640x400

[thorr]

By the way, there seems to be a bug somewhere that sometimes the scaled resolution is either wrong or displayed wrong as seen by using video_info. For example when running Second Reality, at the beginning, it is not always 70.1Hz. It is something else. Once it gets going, it is correct for all the rest of the demo. It is great that as it changes resolutions, it stays perfectly scaled to 640x400@70.1Hz and doesn't cause any audio dropouts throughout the demo.

[geiger9]

This is what I've got in my ini file:

Code: Select all

[ao486]
direct_video=0
vga_scaler=1
vscale_mode=1
video_mode=1600,64,192,304,1200,1,3,46,162000


[video=320x200@70.1]
;video_mode=320,24,49,38,200,2,2,20,13535,0,1 ; 320x200@140.2Hz@31.4kHz DOS CGA/EGA/Adventure games with scanlines
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA era games including 320x200, 320x400, 640x400 @70.1Hz

[video=320x400@70.1]
;video_mode=320,15,108,46,400,13,2,34,15392,0,1 ; 320x400@70.1Hz@31.48kHz This is not finished (not wide enough), but also not needed
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA Games including 320x200, 320x400, 640x400 @70.1Hz

[video=640x400@70.1]
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA Games including 320x200, 320x400, 640x400 @70.1Hz

[video=720x400@70.1]
video_mode=720,15,108,46,400,13,2,34,27983,0,1 ; 720x400@70.1Hz@31.48kHz DOS Text

Yet when I launch the ao486 core my VGA monitor is telling me the horizontal frequency is 75Khz which is outside the operating range of my monitor. Normally the core starts in 720x400 for DOS, right?

I'm pretty far out of my league here. I don't know what most of the terms mean in a modeline. The last number is the pixel clock frequency right? Does that number translate to 75Khz horizontal frequency? None of these modeline calculator type sites I have visited seem to agree with that.

Also, should I disable my forced_scandoubler under the ao486 section or does that matter?

Edit: I realized after that my monitor can't support a resolution of 1600x1200 - mine tops out at 1280 x 1024@60Hz. What is the point of that video mode under the ao486 section anyway? If I change that line to video_mode=6 I still get the same error about 75Khz and out of range.

[thorr]

This is what I've got in my ini file:

Yet when I launch the ao486 core my VGA monitor is telling me the horizontal frequency is 75Khz which is outside the operating range of my monitor. Normally the core starts in 720x400 for DOS, right?

I'm pretty far out of my league here. I don't know what most of the terms mean in a modeline. The last number is the pixel clock frequency right? Does that number translate to 75Khz horizontal frequency? None of these modeline calculator type sites I have visited seem to agree with that.

Also, should I disable my forced_scandoubler under the ao486 section or does that matter?

Edit: I realized after that my monitor can't support a resolution of 1600x1200 - mine tops out at 1280 x 1024@60Hz. What is the point of that video mode under the ao486 section anyway? If I change that line to video_mode=6 I still get the same error about 75Khz and out of range.

You definitely need to disable the forced_scandoubler. That is most likely the problem.
You should change the 1600x1200 mode to something your monitor supports. I would suggest a 4x3 mode like 1024x768. The reason for defining this is to have a catch-all for resolutions that are not yet specifically defined.

[Schyz]

Update: So, for 320x200 games, if they are CGA/EGA era games (earlier Sierra games), use the 320x200@140.2Hz modeline I provided. If they are VGA era games, there should not be scan lines. I created a new modeline that is perfect for many VGA era games. These resolutions are 320x200, 320x400 and 640x400. They all can be integer scaled to 640x400@70.1Hz. I tested with Second Reality and it makes it all the way through and there are no audio glitches except at the beginning. Here is the latest:

[video=320x200@70.1]
;video_mode=320,24,49,38,200,2,2,20,13535,0,1 ; 320x200@140.2Hz@31.4kHz DOS CGA/EGA/Adventure games with scanlines
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA era games including 320x200, 320x400, 640x400 @70.1Hz

[video=320x400@70.1]
;video_mode=320,15,108,46,400,13,2,34,15392,0,1 ; 320x400@70.1Hz@31.48kHz This is not finished (not wide enough), but also not needed
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA Games including 320x200, 320x400, 640x400 @70.1Hz

[video=640x400@70.1]
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA Games including 320x200, 320x400, 640x400 @70.1Hz

[video=720x400@70.1]
video_mode=720,15,108,46,400,13,2,34,27983,0,1 ; 720x400@70.1Hz@31.48kHz DOS Text

I agree with the newmodeline, for VGA 320x200, it looks much better.

I've applied your suggested config and it works great! I'm even having less stability issues than before.

[thorr]

I agree with the newmodeline, for VGA 320x200, it looks much better.

I've applied your suggested config and it works great! I'm even having less stability issues than before.

I agree for VGA. For EGA (King's Quest 1 for example), it looks miles better with the other 320x200 modeline.

I have been testing with demos, and Future Crew's Panic gets pretty far into it with minimal glitches now, but eventually crashes late into the demo. Second Reality is basically perfect now. Other demos still have issues like Crystal Dreams II (slow music). In general, I totally agree that it seems more stable than before.

[Schyz]

I agree for VGA. For EGA (King's Quest 1 for example), it looks miles better with the other 320x200 modeline.

Maybe it's my monitor, I tested Monkey Island 1 on EGA mode and the scanlines felt way too thick.

I have to mention, I use this monitor with a real DOS gaming machine. Maybe a real CGA/EGA monitor+graphics adaptor will have more noticeable scanlines but using this monitor with a real SVGA output and playing dos games looks more similar to the new modeline than the old one.

[geiger9]

This is what I've got in my ini file:

Yet when I launch the ao486 core my VGA monitor is telling me the horizontal frequency is 75Khz which is outside the operating range of my monitor. Normally the core starts in 720x400 for DOS, right?

I'm pretty far out of my league here. I don't know what most of the terms mean in a modeline. The last number is the pixel clock frequency right? Does that number translate to 75Khz horizontal frequency? None of these modeline calculator type sites I have visited seem to agree with that.

Also, should I disable my forced_scandoubler under the ao486 section or does that matter?

Edit: I realized after that my monitor can't support a resolution of 1600x1200 - mine tops out at 1280 x 1024@60Hz. What is the point of that video mode under the ao486 section anyway? If I change that line to video_mode=6 I still get the same error about 75Khz and out of range.

You definitely need to disable the forced_scandoubler. That is most likely the problem.
You should change the 1600x1200 mode to something your monitor supports. I would suggest a 4x3 mode like 1024x768. The reason for defining this is to have a catch-all for resolutions that are not yet specifically defined.

Okay I've disabled the scandoubler but the problem persisted. I switched the video_mode for the ao486 section to 1 for 1024x768. I still get the error about the incoming signal being 75Khz. I deleted the section for video=720x400@70.1 and the error goes away. So I load up the core and DOS loads. When I go to my monitor's OSD it reports 1024x768 like I expect because that's what I set in the ao486 section. The MiSTer video info section in it's menu shows me 720x400 on the top (the original resolution) and 1024x768 on the bottom (the scaled resolution). Cool. I understand why those numbers are in those places. I don't understand why the DOS screen is so squished because I have the aspect ratio set to full screen. Then I load King's Quest 2 and things do not make sense.

When I load King's Quest 2 the monitor OSD now reports 720x400. I set the Vsync to variable and the screen freaks out for a few seconds but then settles. Now when I go to the video info section in the MiSTer menu it shows 320x200 up top (makes sense because that's KQ2's resolution) and the bottom number is 640x400 (makes sense because under the video_mode section for 320x200, that's the resolution specified) The game takes up the full screen as I would expect on original hardware but I don't like that part where the screen goes on the fritz for a second or two when I first load the game and the resolution switches.

So what is it about that modeline that makes my monitor think it's a 75Khz signal?

[thorr]

I agree for VGA. For EGA (King's Quest 1 for example), it looks miles better with the other 320x200 modeline.

Maybe it's my monitor, I tested Monkey Island 1 on EGA mode and the scanlines felt way too thick.

I have to mention, I use this monitor with a real DOS gaming machine. Maybe a real CGA/EGA monitor+graphics adaptor will have more noticeable scanlines but using this monitor with a real SVGA output and playing dos games looks more similar to the new modeline than the old one.

What you are seeing is correct. CGA was ~15.7KHz, and EGA monitors were ~15.7kHz and ~21.78Khz (for 640x350, etc.). VGA monitors were ~31.47kHz.

Using a VGA monitor for EGA games will display them with 31.47kHz (line doubled) modes. However, when games were designed for EGA (and CGA), they had the thicker black scanlines. If you always had a VGA monitor, then it will look normal to you to have line-doubled EGA. On a real EGA monitor, it has the black lines. Try King's Quest 1 and you should see what I mean about how good it looks. It really is striking, to me at least.

Also, another clue about EGA. It is limited to 16 colors. Monkey Island 1 was VGA (256 colors), so it is a bad example. I am going to delete my Monkey Island 2 screenshot because it is not how it should be. Edit, it won't let me delete it so I put a note there about it.

[thorr]

So what is it about that modeline that makes my monitor think it's a 75Khz signal?

You need to have the core set to variable for these modes to work. It sounds like you changed it to variable after starting the core. If you save the settings, make sure you first memorize the key presses to get to that setting in case the monitor can't sync and you can't see what you are doing, so you can change it back to 60Hz.

You do have a CRT monitor, and not a flat LCD, correct? I just wanted to make sure just in case.

My core menu video settings are:
Full Screen
Variable
BGR
1555
Native
Normal

If you need it, here is my mister.ini in case it helps. Be sure to edit it to your setup with the main video modes.

MiSTer.zip

Boots to CRT TV, but is set up for VGA monitor when using ao486

(3.3 KiB) Downloaded 264 times

[Schyz]

My first PC (Olivetti PC-1) was CGA, but that monitor was a blurry mess compared to this one, so I guess that the scanlines would look way less sharp back then when I played MI1 for the first time. Then I jumped to SVGA.

Monkey Island 1 was VGA (256 colors), so it is a bad example. I am going to delete my Monkey Island 2 screenshot because it is not how it should be. Edit, it won't let me delete it so I put a note there about it.

Monkey Island 1 had CGA and EGA support in its initial version.



If you have the "eXo/Flynn Top 300 DOS Pack", you can try different the versions that come with it.

EDIT: I have captured a couple of examples for comparisson, MI1 EGA:

rKSHeho.jpeg (2.18 MiB) Viewed 12715 times

video_mode=320,24,49,38,200,2,2,20,13535,0,1 ; 320x200@140.2Hz@31.4kHz DOS CGA/EGA/Adventure games with scanlines

fQebn96.jpeg (2.14 MiB) Viewed 12715 times

video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA era games including 320x200, 320x400, 640x400 @70.1Hz

a2sDVBB.jpeg (2.3 MiB) Viewed 12715 times

video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA era games including 320x200, 320x400, 640x400 @70.1Hz

99BSMrD.jpeg (2.43 MiB) Viewed 12715 times

video_mode=320,24,49,38,200,2,2,20,13535,0,1 ; 320x200@140.2Hz@31.4kHz DOS CGA/EGA/Adventure games with scanlines

[tsowell]

I use AO486 with a CRT monitor, if this has been merged, is there any documentation about this feature?

There's some brief documentation in the default MiSTer.ini: https://github.com/MiSTer-devel/Main_Mi ... MiSTer.ini

Do I only have to add the following under the [ao486] section

Code: Select all

[video=320x200@70.1]
video_mode=640,16,96,48,400,12,2,35,25175,0,1
vscale_mode=2

[video=720x400@70.1]
video_mode=720,15,108,51,400,11,2,32,28322,0,1

And set Wider HV-Integer scaling?

That was more to demonstrate how the configuration settings work, and I only included the "vscale_mode=2" line in that example to demonstrate that other configuration options can be set in the video sections - I'm not sure if it really makes sense to use it there. You'll have to decide how to configure it based on what modes you are using on the MiSTer cores and how you want to map those to modes supported by your monitor. I don't think there's a one-size-fits-all solution, but it looks like people in this thread are doing a good job of creating and sharing some generally-applicable settings.

[tsowell]

What I really want to confirm is whether supplying a list of resolutions is framework-wide now, and can be used in other cores? Or is it specific to AO486?

You can use these with any core - it's not specific to AO486.

[geiger9]

So what is it about that modeline that makes my monitor think it's a 75Khz signal?

You need to have the core set to variable for these modes to work. It sounds like you changed it to variable after starting the core. If you save the settings, make sure you first memorize the key presses to get to that setting in case the monitor can't sync and you can't see what you are doing, so you can change it back to 60Hz.

You do have a CRT monitor, and not a flat LCD, correct? I just wanted to make sure just in case.

My core menu video settings are:
Full Screen
Variable
BGR
1555
Native
Normal

If you need it, here is my mister.ini in case it helps. Be sure to edit it to your setup with the main video modes.MiSTer.zip

YESSSS that was it! Once I set it to variable, saved core settings and rebooted, the video mode stuff works now and all my stuff fits the screen like I would expect on original hardware. Thank you so much.

[thorr]

You can use these with any core - it's not specific to AO486.

Did you see my post about the bug at the top of page 3 of this post? Can you reproduce this and maybe fix it? Also, since implementing this, my main Mister menu when I first turn on the MiSTer has a background picture and now there is a black bar at the top instead of the full background image on that part. Once the screen times out, the full background returns and it is fine after that. I am not sure if that is just me or not. Thanks!

[flynnsbit]

You can use these with any core - it's not specific to AO486.

Also, since implementing this, my main Mister menu when I first turn on the MiSTer has a background picture and now there is a black bar at the top instead of the full background image on that part. Once the screen times out, the full background returns and it is fine after that. Thanks!

Duplicated, It only happens if you set at least one [video=] option in the .ini and you are right, if you let the screen timeout and fade and then come back it fixes itself. The lines it removes become less and less as you up the resolution, setting ; 4 - 1280x1024@60 for [menu] almost makes it go away. if you don't set vga_scaler for [menu] obviously it doesn't happen, but then you lose the backgrounds.

[Shogun]

Wow those modelines are awesome! This is crazy because I realized I only played PC games scandoubled back in the day on VGA monitors. To see thick fat scanlines like this is throwing me for a loop. Looking around at other discussions on the net I see similar reactions when this topic comes up. Most people talking about this stuff never had the old Tandy/CGA/EGA or even Amiga monitors. I might actually have an old CGA/EGA monitor its an old Mitec but not sure its worth digging out since this is working fine.

a2gtgaQ.jpg (115.03 KiB) Viewed 12717 times

NJ49nRu.jpg (194.54 KiB) Viewed 12717 times

[akeley]

The "fat scanlines" obsession will never cease to amaze me. Doom (and most other games) have never looked like that, and why should they? If you told people back then that having heavily affected window blinds effect will be one of the most desirable display features in 2022 you'd be met with raised eyebrows all round.

But, whatever rocks your boat, and all that jazz

[thorr]

The "fat scanlines" obsession will never cease to amaze me. Doom (and most other games) have never looked like that, and why should they? If you told people back then that having heavily affected window blinds effect will be one of the most desirable display features in 2022 you'd be met with raised eyebrows all round.

But, whatever rocks your boat, and all that jazz

This is a surprising statement. You previously told me you much prefer to play these games on your CRT TV and this is exactly what is happening there. Also, the scan lines add a perceived sharpness to a very low resolution picture. Instead of looking very blocky, your brain fills in the gaps with a sharper image. A single pixel is much smaller (half the size) and looks like higher resolution. Look at the top left corner of the 1 in 100 above. Imagine that line-doubled. It would be a staircase instead of being a nice slanted line.

As stated previously, VGA did not look like that, but EGA and CGA did. However, that does not mean that VGA could not look that way (it does on CRT TV's), and in my opinion which mode you choose depends on personal preference for each game. Sometimes it looks awesome (Sierra games), sometimes it does not (Monkey Island 1 EGA from what I saw from screenshots). I think it depends on how dithered and pixeley the game is vs plain solid colors. The more plain it is, the more I prefer the thicker scan lines. However, if your goal is to make it look correct, then use scandoubled for 256 colors and above, and thick scanlines for 16 colors or less.

[Schyz]

Maybe we need a tool to set the correct modeline from commandline/batch file before loading a game... that way we can have thick scanlines with old CGA/EGA modes and normal ones with VGA.

(Just kidding, I'm happy enough with the current feature)

[thorr]

Maybe we need a tool to set the correct modeline from commandline/batch file before loading a game... that way we can have thick scanlines with old CGA/EGA modes and normal ones with VGA.

(Just kidding, I'm happy enough with the current feature)

I am happy too, but a possible real way of doing this would be to add color depth as a detection feature and set the modeline from that.

[akeley]

This is a surprising statement. You previously told me you much prefer to play these games on your CRT TV and this is exactly what is happening there.

TVs absolutely don't have such exaggerated scanlines, they look completely different - which is one of the reasons I prefer them. Not even mid-range TVL count PVMs look like that.

Also, the scan lines add a perceived sharpness to a very low resolution picture. Instead of looking very blocky, your brain fills in the gaps with a sharper image.

I'm not quite sure it works that way, my brain simply sees big gaps and refuses to fill anything in Anyway, the blockiness is alleviated by non-square pixels on TVs, which is yet another of their pluses. In some of the VGA-native games (such as Doom) the low res blockiness looks kinda good, though it is also very subjective, but overall, yes, I'd much rather have the native look for each mode when I'm on my VGA monitor. Or at least, we should establish that as a baseline and then offer all other options.

As for EGA & CGA I'd like to see some real photos, but, as we know, proper ones are hard to come by.

in my opinion which mode you choose depends on personal preference for each game.

Sure, I said as much in the last sentence of my post.

[thorr]

TV's add bloom which will lessen the thickness of the black scan lines. However, the blockiness is alleviated by the non-line-doubled image (and the bloom which leads to the non-square pixels). So basically, on a VGA monitor, everything looks really sharp but has thicker scanlines, and on a TV, it is sharp but blurred by the bloom. Based on this, I can understand why you would prefer a TV. They are displaying the same thing though. They just look different due to the bloom.

[akeley]

They look different because of the type of mask technology used, and some other factors, so it's not just about the bloom. And scanlines on a VGA monitor are hardly visible. Overall, I prefer the high-end TV look because it's sharp enough, has some natural anti aliasing and you can still see the "pixels" and scanlines. That's what works best for games imo, while for productivity (and some types of games) of course the monitors would be better. In the era of SVGA games eventually the monitors came on top, since they had tiny, non image-breaking scanlines and enough pixels to make curves look proper, not jagged (at least in 2D games).

[thorr]

Correct about the different mask and other technologies making a difference in the look. Scanlines are absolutely visible on a VGA monitor, and more so than on TV's because of the bloom and other factors. The higher the resolution, the less visible they become. Try the Dos Text modeline and the 640x400 modeline. The scanlines are definitely there and look wonderful. They are half as thick as the 320x200 modeline (or maybe less if there is some bloom). Previously, I was upscaling to 1600x1200 that had basically no visibile scanlines, and now I can totally see them and prefer them. Also, the quality of the monitor makes all the difference. A degraded or older technology monitor will be more like a TV than a higher quality VGA monitor. CGA and EGA monitors will probably still look different than the 320x200 modeline on a VGA monitor because the VGA monitor is better at not mucking up the image, and they have different mask technology, etc. However, I would also argue that all my MiSTer cores look amazing on my CRT TV using super clean and sharp component video. This is not how it looked back in the day, but it is much better in my opinion. Same argument could be applied here, but it comes down to personal preference.

[akeley]

Scanlines are absolutely visible on a VGA monitor, and more so than on TV's because of the bloom and other factors.

I didn't say that they are invisible, just that they are much less visible than on a 15kHz TV or a PVM. They are rather subtle comparing and you need to get really close to see them. The size of the display does matter, but on my 17" mid-range Sync Master connected to a DOS PC that's how it is, and I've spent quite some time comparing these things for my photo collection.

Anyway, it doesn't really matter, am not quite sure how have we ended up bickering about it all, and doing so about perception is not very productive anyway As you know I very much appreciate your input and making all these modelines, which is why I use some of them daily and included quite a few of them at that CRT guide I wrote. I will give the new ones a spin soon too, just didn't have time recently to connect my VGA monitor to MiSTer and check all the new stuff.

[thorr]

Let's call it constructive bickering. I don't mind at all and am happy to have a discussion where we possibly disagree. I agree size does matter, and was going to add that to my above comments, but didn't. I am also using a 17" monitor. You should definitely try the new modelines before judging them, lol (just saying, for a bit more bickering). You may find that you love them and change your mind. Especially try the 320x200 mode on King's Quest 1, and the DOS text mode where you can easily (IMO) see the scanlines.

[Schyz]

I'm quite happy with the modes proposed by Thorr above, I was wondering if somebody has a modeline for 320x240.

It's for the DOS version of Shenzhen Solitaire.

[thorr]

I'm quite happy with the modes proposed by Thorr above, I was wondering if somebody has a modeline for 320x240.

It's for the DOS version of Shenzhen Solitaire.

I am planning to work on one when I get a moment. I also want to have one for that mode, especially for Epic Pinball. Most likely it will be 640x480@70.1, but I don't know yet until I work on it. I am also planning to work on 800x600 and others.

[flynnsbit]

I'm quite happy with the modes proposed by Thorr above, I was wondering if somebody has a modeline for 320x240.

It's for the DOS version of Shenzhen Solitaire.

I just set that one to 640x480, so just use the video_mode=6.

Here are the ones I have been tinkering with. These cover Jazz Jackrabbit's weird res, Scorched Earth at 1024x768, Epic Pinball and all the res switches it does.

Code: Select all

[video=320x400@70.1]
;video_mode=320,15,108,46,400,13,2,34,15392,0,1 ; 320x400@70.1Hz@31.48kHz This is not finished (not wide enough), but also not needed
video_mode=640,7,108,30,400,13,2,34,24708,0,1 ; 640x400@70.1Hz@31.48kHz VGA Games including 320x200, 320x400, 640x400 @70.1Hz

[video=720x400@70.1]
video_mode=720,15,108,51,400,11,2,32,28322,0,1

[video=320x200]
video_mode=640,16,96,48,400,12,2,35,25175,0,1

[video=320x199]
video_mode=640,16,96,48,400,12,2,35,25175,0,1

[video=640x400]
video_mode=640,16,96,48,400,12,2,35,25175,0,1
;vscale_mode=2

[video=320x240]
video_mode=6

[video=1024x768]
video_mode=1

[video=800x600]
video_mode=5

[video=404x250]
video_mode=808,24,80,104,500,1,3,14,31580

[thorr]

My goal is to have exact vertical refresh timings that match all the source frequencies. Using video_mode=6, etc. is fine for an interim solution, but not what I want for the long term, unless the vertical refresh frequencies match. I haven't spent the time yet to try all these other modes in DOS yet to see how they come up, but plan to.

video_mode=640,16,96,48,400,12,2,35,25175,0,1 comes out to 31.47kHz at 70.09Hz
video_mode=640,7,108,30,400,13,2,34,24708,0,1 comes out to 31.48kHz at 70.10Hz

I am not sure if the first one is correct, but that was the example given. The screen says 70.1Hz, and that is what I made the custom mode to (the second line above). I wish there was a way to have the core set the exact timings that it is receiving into the scaler, rather than having to define custom modes in the INI file, or at least print out more information about the timings it is receiving in the information box. The problem with setting it directly is the 15kHz modes (320x200) will fail on VGA monitors.

video_mode=720,15,108,51,400,11,2,32,28322,0,1 comes out to 31.68kHz at 71.19Hz <--- this one is definitely not ideal
video_mode=720,15,108,46,400,13,2,34,27983,0,1 comes out to 31.48kHz at 70.10Hz