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Accuracy w/ CRT monitor

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First post, by cbn91

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With a CRT monitor (640x480@85hz), I'd like to know which dosbox (original, Staging, X, w/e else there is) and output will get me the most accurate display in terms of how games were originally seen. I'm aware I can't expect 100% accuracy, but I'm just looking for as much accuracy as I can reasonably obtain. I've read about and tested both bilinear and nearest-neighbor interpolations, and although I can clearly see the difference between the two, I don't understand which is more reflective of how the games were originally displayed.

Reply 1 of 14, by jh80

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Can you clarify? You've got a CRT monitor hooked up to a modern PC and want to display DOS games on it using some form of emulator?

If so, could you give specs of your setup? And how are you connecting to the CRT?

Reply 2 of 14, by cbn91

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I have a relatively modern PC (i7-6700k cpu/nvidia 970gtx) with a Compaq FS7600 CRT (capable of 1024x768 but I'm lowering it to 640x480 to better scale 320x200/240 games), and I'm using a VGA to DVI adapter. I'm using dosbox to play a wide variety of games.

I'm able to play games just fine; my question is only about visual accuracy. For now, I suppose it'll be easier if I just ask about one game: Warcraft 1. If I'm playing Warcraft 1 in dosbox (original or any of its forks) with the aforementioned setup, what settings (output/interpolation/etc.) would help to display the game as it was originally intended to look (or at least as close as possible)?

Reply 3 of 14, by theelf

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cbn91 wrote on Today, 03:08:

I have a relatively modern PC (i7-6700k cpu/nvidia 970gtx) with a Compaq FS7600 CRT (capable of 1024x768 but I'm lowering it to 640x480 to better scale 320x200/240 games), and I'm using a VGA to DVI adapter. I'm using dosbox to play a wide variety of games.

I'm able to play games just fine; my question is only about visual accuracy. For now, I suppose it'll be easier if I just ask about one game: Warcraft 1. If I'm playing Warcraft 1 in dosbox (original or any of its forks) with the aforementioned setup, what settings (output/interpolation/etc.) would help to display the game as it was originally intended to look (or at least as close as possible)?

Then you need to output 640x400

No idea such gpu can work with winmodelines, try it

https://www.geocities.ws/podernixie/htpc/modeline.html

Reply 4 of 14, by jmarsh

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DOSBox isn't made to replay games in original resolution, the whole idea is that it uses a constant output mode (decided by the user) and maps any input mode into it.

If you want to experience DOS games as they were, get a DOS machine.

Reply 5 of 14, by jh80

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Have you already followed Phil's video and the guide on Reddit it's based on?

https://www.youtube.com/watch?v=pQ-DWEY3E7M

https://www.reddit.com/r/emulation/comments/l … _dos_emulation/

You can get pretty far using DOSBox and a CRT if your graphics card can support the custom resolutions. The main idea is to set DOSBox to use the game's original resolution and not adjust the aspect ratio (the CRT will do that for you). There are still limitations discussed in the thread but it's basically very good.

Reply 6 of 14, by theelf

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jmarsh wrote on Today, 07:03:

DOSBox isn't made to replay games in original resolution, the whole idea is that it uses a constant output mode (decided by the user) and maps any input mode into it.

If you want to experience DOS games as they were, get a DOS machine.

This is not true, dosbox can output original resolutions without any problem

Reply 7 of 14, by jmarsh

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theelf wrote on Today, 09:31:

This is not true, dosbox can output original resolutions without any problem

No it can't. SDL provides no method to select the output framerate. Nor can it tell the GPU directly which resolution to use; it can ask the OS video driver for a certain mode, but the video driver is free to use whatever it thinks is best.

Windows drivers also stopped properly supporting paletted video modes around Vista, which practically all DOS VGA games use. So even the colors aren't technically correct and are an approximation.

Reply 8 of 14, by NeoG_

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All OP is asking for is how to get as close as possible, not a 1:1 recreation

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Reply 9 of 14, by jmarsh

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That's simple: get a decent LCD that can do at least 1600x1200@144Hz, fullresolution=1600x1200, aspect=true, output=opengl, glshader=sharp. All output will be scaled to 1600x1200 with either nearest neighbour or bilinear with blurring minimized by the high resolution.
Trying to use a CRT is just making things more difficult because the OS/GPU aren't designed to accommodate them any more.

(It would actually be easier to use a USB DAC with a custom DOSBox build, if someone really wanted to go that route.)

Reply 10 of 14, by theelf

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jmarsh wrote on Today, 09:56:
theelf wrote on Today, 09:31:

This is not true, dosbox can output original resolutions without any problem

No it can't. SDL provides no method to select the output framerate. Nor can it tell the GPU directly which resolution to use; it can ask the OS video driver for a certain mode, but the video driver is free to use whatever it thinks is best.

Windows drivers also stopped properly supporting paletted video modes around Vista, which practically all DOS VGA games use. So even the colors aren't technically correct and are an approximation.

The refresh rate is in modeline side, you can do a 640x400 modeline at 70,72,75hz that will cover almost all vga games, you can compile and use a second dosbox for ega/cga if you want 60hz and use 644x400 for example, and you will have both options, is what i do

But yes dosbox change resolution, work very well for me, what SDL cant do is select refresh rate, you need to do yourself in modelines

the OP have a 970, he can use XP in case a modern windows give problem, dosbox in XP work excelent for me, scummvm same, use custom resolutions without problem, and is sdl too

Last edited by theelf on 2026-05-21, 10:51. Edited 1 time in total.

Reply 11 of 14, by jh80

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jmarsh wrote on Today, 09:56:

No it can't. SDL provides no method to select the output framerate. Nor can it tell the GPU directly which resolution to use; it can ask the OS video driver for a certain mode, but the video driver is free to use whatever it thinks is best.

Windows drivers also stopped properly supporting paletted video modes around Vista, which practically all DOS VGA games use. So even the colors aren't technically correct and are an approximation.

In practice, the first point is not helpful since the user can provide the correct resolution and framerate via custom resolution tool. Yes, it requires more work, but it is not the case that you cannot display games via DOSBox at their intended resolution and framerate on a CRT.

The second point just seems like a dig against DOSBox (in the DOSBox section of the forum), which is certainly not relevant to the thread that I can see.

Reply 12 of 14, by jmarsh

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jh80 wrote on Today, 10:51:

In practice, the first point is not helpful since the user can provide the correct resolution and framerate via custom resolution tool. Yes, it requires more work, but it is not the case that you cannot display games via DOSBox at their intended resolution and framerate on a CRT.

But then you're stuck with one refresh rate per resolution. That's not how (S)VGA cards worked. Some games may work while others require different custom framerates, so you're stuck constantly switching things. It's better to simply use a high refresh rate (i.e. 144Hz) where you're not going to get framedrops and the frametimes are small enough to minimize juddering from rate mismatch.

The second point just seems like a dig against DOSBox (in the DOSBox section of the forum), which is certainly not relevant to the thread that I can see.

I'm speaking as someone who's done considerable work on DOSBox (including the shader implementation). It's not a "dig against DOSBox", it's advice to prevent people wasting their time trying to make it do something it wasn't intended to do.

Reply 13 of 14, by theelf

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jmarsh wrote on Today, 11:09:
But then you're stuck with one refresh rate per resolution. That's not how (S)VGA cards worked. Some games may work while others […]
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jh80 wrote on Today, 10:51:

In practice, the first point is not helpful since the user can provide the correct resolution and framerate via custom resolution tool. Yes, it requires more work, but it is not the case that you cannot display games via DOSBox at their intended resolution and framerate on a CRT.

But then you're stuck with one refresh rate per resolution. That's not how (S)VGA cards worked. Some games may work while others require different custom framerates, so you're stuck constantly switching things. It's better to simply use a high refresh rate (i.e. 144Hz) where you're not going to get framedrops and the frametimes are small enough to minimize juddering from rate mismatch.

The second point just seems like a dig against DOSBox (in the DOSBox section of the forum), which is certainly not relevant to the thread that I can see.

I'm speaking as someone who's done considerable work on DOSBox (including the shader implementation). It's not a "dig against DOSBox", it's advice to prevent people wasting their time trying to make it do something it wasn't intended to do.

You can always define a config per game, write a batch file and load for problematic games

I already ask for this some time ago, work well

Change resolution and machine inside dosbox?

Of course you can use different config files and thats all, i just like to do inside dosbox, more like a real PC

Reply 14 of 14, by jh80

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jmarsh wrote on Today, 11:09:

But then you're stuck with one refresh rate per resolution. That's not how (S)VGA cards worked. Some games may work while others require different custom framerates, so you're stuck constantly switching things. It's better to simply use a high refresh rate (i.e. 144Hz) where you're not going to get framedrops and the frametimes are small enough to minimize juddering from rate mismatch.

Again, everyone acknowledges that it's not a perfect solution, but it is possible to set game-specific custom framerates and switch between them when changing games.