The rendering defaults for DOSBox games (especially VGA mode 13) haven't changed since the introduction of GOG in 2008. Now that widescreen LCDs and modern Windows versions everywhere they should be overhauled.

First, the default renderer choice is Surface, which should be changed to Overlay. Overlay works everywhere and supports hardware scaling, so there is no reason to not use it.

Scaler should set to None by default, because that's a thing the GPU hardware can do better with better looking results.

Aspect ratio correction should be enabled by default, there is no "automatic correction" like on 4:3 CRTs anymore. 16:10 is not the correct aspect ratio for DOS games and LCDs will stretch them like that without correction.

Fullscreen resolution should be set to "desktop". DOSBox should not switch resolutions on LCDs, especially because the DOS-typical low resolutions aren't supported anymore by modern GPUs (and neither by Windows). Doing upscaling multiple times (once by DOSBox, once by LCD) makes the games look way worse.

TL;DR: DOSBox defaults should be changed to:

[sdl]
fullresolution=desktop
output=overlay

[render]
aspect=true
scaler=none

The DOSBox configurator shoud be updated accordingly.

Different games use different options, and there are so many different machines out there, you'll never satisfy everyone with any setting standards.

Best to just modify them yourself to what works with you.

Regardless of the game GOG's defaults are the same for all DOSBox games in my library and they are very suboptimal for modern systems.

The software scaler normal3x simply triples the pixels, which is never look good if the output resolution doesn't exactly match the display pixels. It's never going to look good on games with non-square pixels (the majority of all DOS games). All other methods use the GPU hardware scaler which works way better. GDI surface draw calls are deprecated since the DirectX upgrade for Windows 95, 20 years ago. The only reason to use them is if you have non-DirectX-compatible graphics drivers, because you upgraded from Windows 3.1 and kept your ISA VGA around.

Of course, such a scenario is completely ridiculous, because such hardware doesn't have abilities to run DOSBox and it doesn't have to, because it can run DOS games natively.

In fact, those old rendering methods are going to cause more compatibility issues, than any other setting. Modern GPUs since 2006 have GDI functions removed and beginning with Windows Vista, they aren't supported anymore and emulated through the CPU. So surface it's not only a bad default, it's a renderer which should be removed from DOSBox completely.

People keep being confused about what aspect=true does. It does not help displaying 4:3 content on 16:9 monitors, or anything like that.

It mostly just affects games in 320x200, the pixels of which are not square. With scaler=none, it essentially doubles every fifth line to make it 320x240. This is a very noticeable distortion. Adding scaler=normal3x minimizes it a bit, you then get lines of 3 or 4 pixels tall instead of lines of 1 or 2 pixels tall. Still noticeable, but a smaller difference.

To eliminate the distortion entirely, the image should be scaled 5x horizontally and 6x vertically, making it 1600x1200, I don't think dosbox supports this and my screen isn't even tall enough.

Pillar-boxing would be happening (or not) in the output= driver. I'm not very familiar with the various outputs, but any scaling that they do may trade crispness for uniformity, and produce a more pleasant to look at outcome.

If the output blows the image to fill the entire screen but the monitor being used actually is 4:3 or has a 4:3 option, it might be best to just use that and set aspect=false and scaler=none.

Good idea. Maybe one could even further optimize the settings depending on the existing TV / resolution / graphics hardware.

When I play a DosBox game next time I will investigate this further. But in principle GOG should try to get the optimum out of it already.

Don't bother go over to Vogons and tell them about this or ask other things. They will flame you so bad.

You just got, why using a software scaler gives bad results. That was the whole point of this thread.

output=overlay scaler=none aspect=true doesn't add any lines or pixels anywhere. It just tells the hardware scaler to keep a 4:3 aspect ratio for 4:3 games.

Please try out the settings I suggested before making assumptions.

It works with any fullscreen or window resolution and it works with any game resolution, regardless if it has square or non-square pixels. The GPU hardware scaler knows how to do it right, when you tell DOSBox to keep the native resolution instead of switching LCDs into weird unsuable resolutions like 1600x1200 (like suggested by you). Why should I go there? I'm just suggesting more sensible defaults for GOG releases, which work better on contemporary hardware. Which is the point of GOG, isn't it? If I want to run old games on ancient hardware, I wouldn't care about DOSBox.

GDI isn't necessarily what's used for rendering. If you refer to the official DOSBox Wiki and follow the link, you'll notice a post from Gulikoza, a well-known DOSBox port programmer, who lists what the modes do. Specifically, whether Surface uses DirectDraw or GDI is conditional based on the environment variables for SDL (search that page for win32).

Just a minor correction of info. Carry on...

See if you can convince the guys over at the Vogon forums to pool the SDL builds into .80, what I would assume at this point. Not everyone in the public eye knows/can be bothered with the SDL builds, and I'm not entirely sure what is preventing them from doing a new mainstream release. I'm sure there have been thousands of bugfixes and compatibility issues resolved since .74. All they need to do is choose a freeze point and then get to work on compiling.

...On the other hand, development cycles seem to have gone to hades in a handbasket ever since Minecraft arrived on scene. Sorry, just gently glaring at any software still in development that doesn't have an active roadmap and would be content to wander aimlessly like Starbound.

This tends to happen to voluntarily developed software. projects. After some time, people lose interest and move on.

But there is a solution: If someone is a a commercial entity who builds its business on selling a large stock of good old DOS games, one can make some of that income go back to free software projects one depends on. Or even employ a developer experienced with such a project to move the release of the business-critical middleware forward.

Just my two cents. :-)

Though I agree that there could be made a lot of improvements to default Dosbox settings, there is also the issue that GOG must maintain maximum compatibility and also different users prefer different settings.
I suggest everyone to read up on this page. That is just half the story, normal3x triples the pixels but only in windowed mode, which isn't necessarily a bad thing.
The other thing is that the scaler can be used as a filter/shader depending on which video output, not all videomodes support this though.

As for aspect=true is only for games that are 320x200 resolution (which actually isn't 4:3), games that use VGA resolutions of 640:480 for example don't need this.

But if you want a game that in my oppinion is badly setup by GOG then it are the Pinball Gold Pack games, which use way too high blocksize and soundbuffers (4x higher than default) which made the soundeffects play with half a second lag. I went back to Dosbox default settings, the only thing is it works only with ddraw or overlay as opengl has sounddistortion which is probably why GOG did this but it makes the game almost unplayable.

I do make most of these changes, but the image produced with scaler set to none is too blurry for me. Perhaps it depends on the game, but here's an example where I only changed the scaler.

The aspect ratio in all your screenshots is wrong. This is how it's supposed to look like:

Windowed: http://i.imgur.com/XWs1s6r.png
Fullscreen: http://i.imgur.com/F9I8jZG.jpg

When going for fullscreen, you must make sure, that you have fullresolution=desktop, otherwise DOSBox switches your LCD to a lower resolution, your LCD scaler kicks in and stretches everything for a second time. Then, of course it looks awful and blurry.

Also note that a 1995 DOS game is not intended to look like a 2015 "retro-style" iPad pixel game. The bicubic rounding by the hardware upscaler is correct behavior and actually improves the image quality of games originally targeted at 4:3 CRT monitors with round pixels. See how the original developers used dithering to simulate additional color shades? This technique doesn't work with "normal3x" creating square pixels and checkerboards instead.