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I went there, expecting some information how DOSBox was hacked to emulate some old-fashioned CRT-visuals and output 4K-content. Got instructions on how to conve
by fock 7y ago
I went there, expecting some information how DOSBox was hacked to emulate some old-fashioned CRT-visuals and output 4K-content. Got instructions on how to convert AVI to another format with ffmpeg. Great!
- vardump 7y agoIt gets even pixel aspect ratio wrong, or rather, doesn't account for it in any way. In some modes, like 320x200, pixels are 20% taller than "normal" square pixels. If you don't account for that, everything looks vertically squished.
- neatcoder 7y agoIsn't that the right DOSBOX behavior? I think it should maintain the original aspect ratio as it looked in the old CRT monitors. I remember drawing circles in CRT monitors on IBM PCs and the circles did look vertically squished. Why should DOSBOX or FFMPEG alter that original aspect ratio? Altering that artificially would be like lying about what the real output looked like in the good old days.
- klodolph 7y agoIf you use DOSBox with default settings, the pixel aspect ratio will be square. Old PCs, as you remember, had non-square aspect ratios, and so the graphics will look incorrect, they will look squashed horizontally.
- susam 7y agoI am running DOSBox with default settings. I draw a square and then a circle with these lines of Logo code: REPEAT 4 [FD 1 RT 90] REPEAT 360 [FD 1 RT 1] I find that both the square and the circle appear squashed. On measuring the pixel height and width of these figures as they appear on my desktop, I see that the square is 400 pixels in width and 320 pixels in height. That's an aspect ratio of 5:4. Similarly, the circle is 460 pixels in width and 364 pixels in height. That's an aspect ratio of 1.26:1. I find the same aspect ratio in full screen (Alt + Enter) mode too. In the full screen mode, the square is 200 pixels in width and 160 pixels in height and the circle is 230 pixels in width and 182 pixels in height. Here are the screenshots: - https://imgur.com/l9YpTqp https://imgur.com/l9YpTqp - https://imgur.com/WTwfSzq https://imgur.com/WTwfSzq - https://imgur.com/CjMYJN6 https://imgur.com/CjMYJN6
- Crinus 7y agoEdit the dosbox configuration file and change aspect=0 to aspect=1, it'll resize the output to be aspect correct but it might be a bit blurry (IIRC the scale3x scaler will do a pixel-scale and then that will be bilinearly resized, giving mostly crispy pixels with a bit of in-between bleeding which is probably the best you can get with an LCD monitor)
- susam 7y agoWith aspect=1, the square is 400 pixels high and 384 pixels wide, not exactly an aspect ratio of 1:1 but quite close, 1.04:1. The parent of my earlier comment, i.e., the one by klodolph, claims that the pixel aspect ratio would be square by default in DOSBox, so I thought I would verify it once. As per my experiments, that does not seem to be the case.
- fireattack 7y agoI think what he meant is that, The pixels are square in DOSBox, but the graphics from these old programs are designed for non-square pixel ratio. So, if you display it with square pixel, the display aspect ratio will be wrong. (Of course, this still contradicts with what neatcoder said, but I can't remember if these programs were "squished" on CRTs or not.)
- susam 7y agoSee these screenshots of SCREEN 2 in GW-BASIC running in DOSBox: - https://imgur.com/NZUGL1e https://imgur.com/NZUGL1e (aspect=0) - https://imgur.com/rnQOfA4 https://imgur.com/rnQOfA4 (aspect=1) The one with aspect=1 looks very odd.
- klodolph 7y agoThe one with aspect=1 looks incorrectly configured. There are a number of different graphics modes, they have different pixel aspect ratios, you can also adjust the monitor, it is possible that back in school you were using a different mode or a different monitor. I think there are some other factors that can affect this.
- NikkiA 7y agogood CRT monitors would auto-sync and get the aspect ratio right.
- susam 7y ago> It gets even pixel aspect ratio wrong, or rather, doesn't account for it in any way. You are right. I did not account for the aspect ratio. I will consider fixing the aspect ratio and updating the images.