Hi everyone,
I have recently made a tutorial on youtube that shows how to increse the graphics quality of games running in DOSBox, and although some of you may know how to do this, I'm hoping that some may find this very useful. It basically just smooths down the pixels to make a nicer picture on the screen, and requires no downloads to do.
https://www.youtube.com/watch?v=l_uFMyKjdDI
Thanks!
The Nerdy Plane

Tutorials and help never hurt. Have a +1 for trying to be helpful, even if all the pertinent information is in the DOSBox documentation.

In my middle-age phase I tend to forget how young gamers on gaming forums can be :)

Not a bad video on the whole, although you need to work on how your video renderer is compressing the final video. There's some rather irritating sporadic blockiness there.

Also, it's probably worth mentioning that the edge filter shaders like Supereagle are very much a matter of taste. I personally don't consider them to be an improvement of any kind - outlines look horribly inconsistent and detail often gets lost when techniques such as dithering are used.

I know it's not everyone's thang but I prefer to avoid any kind of filtering (even bilinear filters) and to keep the pixels as clear, visible, square and equal as possible - otherwise known as pixel-perfect scaling. You can achieve a 1:1 pixel scale by setting

fullresolution=0x0
output=overlay
aspect=false
scaler=none

For most games running in common resolutions like 320x240, 640x400 or 640x480, that'll give you a very small display on your monitor/TV in fullscreen mode that should match the pixel output of the game precisely to your monitor or TV's output (unless your device doesn't output 1:1 even in native resolution, for instance if you have some kind of overscan or underscan problem).

Common resolutions back in the 1980s and 1990s were 320x240, 640x400, 640x480, some later games also used 800x600 and 1024x768. There's not a single standard resolution that vertically divides neatly into a 1080p display resolution, so if you want pixel perfect scaling, you have to "put up" with black borders (however, by way of exception, if you have a 4K display, a vertical resolution of 2160 does divide neatly into 240 for 320x240 games).

On the resolution that your game uses, you should be able to bump up the scaler to normal2x or normal3x. The Daum Café DOSBox build (and probably a few other custom builds) also supports normal4x and normal5x. This is important in combination with "output=overlay" and "aspect=false" in that it preserves pixel-perfect upscaling, unless the resultant upscaled resolution is less than your fullscreen resolution, in which case it'll downscale it again with less than ideal results.

fullresolution=0x0
output=overlay
aspect=false
scaler=none

So: if you have a DOS game that ordinarily runs at 640x480, your best bet for pixel-perfect scaling is to run with the following settings:

fullresolution=0x0
output=overlay
aspect=false
scaler=normal2x

On an 1080p HD monitor or TV, this should output a 640x480 framebuffer upscaled 2x to 1280x960 and centred on a 1920x1080 display, with the customary 4:3 aspect ratio black borders to the left and right as well as 60-pixel borders at the top and bottom.

Of course, DOSBox's very buggy nature means that this can be very unpredictable in terms of what actually happens.

Alternatively, you can also set the fullscreen resolution to an absolute multiple of your game's resolution and then configure your TV or monitor manually to output a pixel perfect display:

fullresolution=1280x960
output=overlay
aspect=false
scaler=normal2x

Some displays don't allow this, and others still don't like outputting 640x480 and just treat it as an analogue signal over HDMI. Also, your video card driver may need be reconfigured to prevent your GPU doing the upscaling before it reaches your TV as a prepared 1080p signal.

Thanks, the blockiness isn't a problem with the compression or anything... it's our new 'smart' BT router, the BT Hub6. Before we got the upgrade it was fine... oh well.
Also, I know what you mean about the detail getting lost, but I prefer the smooth edges, and supereagle also gets rid of the different shaped pixels, without having to run the game in the non-scaled, original res etc options. Thanks!

You are not alone. I too prefer pixel-perfect scaling.

I guess its just personal taste... I would rather have a smoother looking overall picture at the expense of a few minor details.

Thanks so much, I really appreciate that!
How about 'How to add any DOSBox game to your Steam library', I'll try to make that soon if anyone is interested.

Yeah, me too. Except.. You're not mentioning 320x200, which is very common and comes with an aspect ratio problem because it's pixels aren't square. You would have to scale it all the way to 1600x1200 for crisp pixels in the intended shape.

Failing that, you probably want aspect=true and some upscaling to minimize the distortion.

320x200 in a 4:3 display is much much more common than 320x240.

I guess I am the same. I prefer my DOSBox (and MAME and WinUAE and whatever) without any extra filters, SuperUltraEagleV6 etc. I recall when I was playing the first Monkey Island game years ago, I happened to have some of those filters on in DOSBox. In one scene with one character, something seemed odd so I went ahead and disabled any filters I could find, to make it so plain as possible.

Yep, using that filter (whichever it was) made it look like one character had no pupils at all in his eyes (small black dots). Somehow the filter seemed to "smooth it out", getting rid of his pupils.

At that point I decided that I always disable such filters for old low res games, if possible.

Made another Dosbox tutorial, if anyone's interested. I'm not going to keep on posting here, just thought these were slightly relevant: https://www.youtube.com/watch?v=rvhYnq-E0bo