26 (editado por Ronan 11-04-2010 17:59:02)

Re: Low-res screenshots

Here are the methods I developed for doubled and quadrupled screenshots. I have a Mac and use Seashore (a simpler version of Gimp) for image editing, and Pixen to save the images as PNGs (because the PNGs saved with Seashore may suffer from colorimetric issues on other computers). Any feedback on the images, the methods or my explanations is of course welcome.

Doubled screenshots

http://img130.imageshack.us/img130/2245/2xtfiv.png
Other examples here:
http://img59.imageshack.us/g/2xms.png/

General procedure

1° - Using linear/bilinear interpolation, double the vertical resolution and adjust the horizontal resolution to get an aspect ratio of 4:3.
2° - Add a bit of horizontal blur.
3° - Increase the contrast: +0.25. (In Seashore, this has about the same effect as duplicating the base layer in Overlay mode with an opacity of 60%.)
4° - Add a scanline effect by copying the PNG below in a new layer in Overlay mode. The PNG has an alpha channel. If you use another application than Seashore, you might have to shift this new layer one pixel up.
http://img638.imageshack.us/i/2xnewezlesswhite.png/
5° - Strengthen the scanlines using the same PNG in a new layer in Multiply mode, with about 20% opacity.


Step-by-step procedure with Seashore:

1° Double the screenshot
- Open your picture with Seashore.
- Image/Scale..., uncheck "Keep proportions", write 200% for the vertical resolution, and then write in the field "Width" the number of pixels needed to get a 4:3 aspect ratio, press Tab, choose "Linear interpolation" and press Enter.

2° Enhance horizontal blur
- You need the "Layers" window to be open. If it's not: Window/Utility Windows/Show Layers.
- Duplicate the base layer (the only one at this point) by pressing the second button at the bottom of the Layers window, and choose 50% for the opacity.
- Shift the new layer one pixel to the right by pressing once the right arrow on your keyboard.
(In order to see the whole picture, in the Layers window, "Show all" must be checked)
- Flatten everything to get a single layer: Image/Flatten Image

3° Increase contrast
- Selection/Effects/Colours/Brightness and Contrast, choose +0.25 for the contrast

4° Apply scanline effect
- Create a new layer by pressing the first button at the bottom of the Layers window.
- Open the PNG file below with Seashore:
http://img638.imageshack.us/i/2xnewezlesswhite.png/
- Copy, close and paste: Cmd+A, Cmd+C, Cmd+W, Cmd+V, Cmd+F
- In the Layers window, choose Modes/Overlay.

5° Strengthen the scanlines
- Duplicate the new layer by pressing the second button at the bottom of the Layers window.
- In the Layers window, choose Modes/Multiply, then choose an opacity of 20%.

The image is first saved as TIFF with Seashore, and then as PNG with Pixen, to avoid possible colorimetric problems.
Here are some other scanline PNGs if you want to make some tests:
http://img138.imageshack.us/i/2xnewezalpha.png/
http://img138.imageshack.us/i/2xnewezdark.png/



Quadrupled screenshots

http://img708.imageshack.us/img708/6746/4xtfivcrop.png
Other examples (full size) here:
http://img692.imageshack.us/g/4xsfiii.png/


General procedure

1° - Without interpolation, double the vertical resolution only.
2° - Using linear/bilinear interpolation, double the vertical resolution again and adjust the horizontal resolution to get an aspect ratio of 4:3.
3° - Increase the contrast (+0.25). (In Seashore, this has about the same effect as duplicating the base layer in Overlay mode with an opacity of 60%.)
4° - Add a scanline effect by copying the PNG below in a new layer in Overlay mode. The PNG has an alpha channel. If you use another application than Seashore, you might have to shift this new layer two pixels up.
http://img19.imageshack.us/i/4xnewezter.png/
5° - Strengthen the scanlines using the same PNG in a new layer in Multiply mode, with about 20% opacity.


Step-by-step procedure with Seashore:

1° Double the vertical resolution
- Open your picture with Seashore.
- Image/Scale..., uncheck "Keep proportions", write 200% for the vertical resolution, press Tab, choose "No interpolation" and press Enter.

2° Final upscaling
- Image/Scale..., uncheck "Keep proportions", write 200% for the vertical resolution, and then write in the field "Width" the number of pixels needed to get a 4:3 aspect ratio, press Tab, choose "Linear interpolation" and press Enter.

3° Increase contrast
- Selection/Effects/Colours/Brightness and Contrast, choose +0.25 for the contrast.

4° Apply scanline effect
- Create a new layer by pressing the first button at the bottom of the Layers window.
- Open the PNG file below with Seashore:
http://img19.imageshack.us/i/4xnewezter.png/
- Copy, close and paste: Cmd+A, Cmd+C, Cmd+W, Cmd+V, Cmd+F
- In the Layers window, choose Modes/Overlay.

5° Strengthen the scanlines
- Duplicate the new layer by pressing the second button at the bottom of the Layers window.
- In the Layers window, choose Modes/Multiply, then choose an opacity of 20%.

The image is first saved as TIFF with Seashore, and then as PNG with Pixen, to avoid possible colorimetric problems.

Here are some other scanline PNGs if you want to make some tests:
http://img19.imageshack.us/i/4xnewezqua.png/
http://img19.imageshack.us/i/4xnewezbis33.png/
http://img109.imageshack.us/i/4xnewezbis50.png/
http://img715.imageshack.us/i/4xkozh.png/


Remarks:

The advantage to use the overlay mode is that you can not only get a round spot, but also make the diameter of spot increase with spot intensity (and independently for the red, green and blue components). This effect is of course less visible on the doubled screenshots.

The blur should be mostly horizontal. That is why I always use horizontal linear interpolation when upscaling the screenshot. I also use some vertical interpolation (for reasons of symetry of the scanline effect), but the interpolated pixels are eventually darkened, so that the image is kept sharp.

The PNGs used for the scanline effect have an alpha channel. That was necessary in order to use the same PNGs both to apply the scanline effect and then strengthen the scanlines.

27

Re: Low-res screenshots

Thank you, Ronan. "Doubled" screenshots have the usual issues, but "quadrupled" screens are very nice, especially when you add CRT-style curvature. I still want to ask you about non-scaled/slightly upscaled screenshots too but this is related more to the site design and I need to upload stuff, so later on.

28 (editado por Ronan 31-03-2010 13:26:26)

Re: Low-res screenshots

I had actually nearly forgotten about these doubled screenshots. When you write that they have the usual issues, do you mean the general issues of any doubled screenshot, or the specific issues of the examples I provided you a while ago? Because the above examples shouldn't have the same PNG-related colorimetric problems. In fact, doubled and quadrupled screenshots now feature nearly identical colors. So if you still don't like these doubled screenshots, the only reason I can see is the vertical interpolation... Here is a doubled screenshot made without vertical interpolation, if you want to compare. Of course, the beam spot doesn't appear round anymore and is not symetrically depicted:
http://img197.imageshack.us/img197/9963 … terpol.png


As for the quadrupled screenshots, the scanlines may be too dark. But it is very easy to adjust (opacity value in step 5). Do you think the screenshots should be a bit more blurry?

I think non-scaled screenshots should only be corrected by increasing the contrast (possibly using the curves tool for more faithfulness). Slightly upscaled screenshots would not look very sharp, except if you don't use any vertical interpolation, but then you would get ugly artifacts because of the few vertically-doubled pixels. Any screenshot should of course be adjusted to a 4:3 aspect ratio with horizontal interpolation. I guess you already know very well about this, but I will be glad to try to help you if I can. So just let me know when you need such screenshots.
No need to talk about them here and now, but here are already three examples: non-scaled, slightly upscaled using vertical interpolation, and slightly upscaled without interpolation:
http://img195.imageshack.us/i/1xtfiv.png/
http://img191.imageshack.us/i/12xtfivinterpol.png/
http://img534.imageshack.us/i/12xtfivjaggy.png/

29

Re: Low-res screenshots

Ronan escribió:

I had actually nearly forgotten about these doubled screenshots. When you write that they have the usual issues, do you mean the general issues of any doubled screenshot, or the specific issues of the examples I provided you a while ago?

The former, though they still need curvature and perhaps additional blur to get a proper conclusion, but I find no colorimetric problems. Anyway, discussing methods for this screen size is officially worthless at this point. Moving on.



As for the quadrupled screenshots, the scanlines may be too dark. But it is very easy to adjust (opacity value in step 5). Do you think the screenshots should be a bit more blurry?

I think it does depend on the case really. I'd still darken them a little bit and would saturate the colors accordingly.



I think non-scaled screenshots

Thanks for the samples, but the approach here would be totally different. I want to let you see what I mean with pictures so let's just leave it at that for now. It's indeed more a subject for the development subforum and I believe I need to solve the PNGs' issue first off in order to not repeat the stupid charade from before.

30 (editado por zinger 11-04-2010 10:20:42)

Re: Low-res screenshots

OK, here we go. I think I've gotten the hang of the basics:

http://www.soundshock.se/dump/SCR_MD5.png

What confuses me though is games that run at custom resolutions (like SFC Prince of Persia or certain cinematics, which run at 512*448 - should I resize that to 597 x 448?):

http://www.soundshock.se/dump/POP_SF3.png

Another thing is PC88 games (and several other computer games I'm sure) that run at different weird resolutions, and with different aspect ratios it seems:

http://www.soundshock.se/dump/WER1.png

Some tips and comments would be very much appreciateed.

31

Re: Low-res screenshots

zinger escribió:

OK, here we go. I think I've gotten the hang of the basics:

http://www.soundshock.se/dump/SCR_MD5.png

I'd say so. But please, don't miss that the final conclusion in this thread, as I told you, is that ~ 640 x 480 is a pretty bad size for low-res screenshot purposes. If you're starting off right now, you should go for this size and these results:

http://img692.imageshack.us/g/4xsfiii.png/

Or better yet, photograph the RGB CRT.



What confuses me though is games that run at custom resolutions (like SFC Prince of Persia or certain cinematics, which run at 512*448 - should I resize that to 597 x 448?):

http://www.soundshock.se/dump/POP_SF3.png

Well, I'm not really sure that SFC POP runs at the system's high res mode (Are you? How?), but for those which do, you should get the screens to have a 4 : 3 aspect ratio, yeah. But it's exactly the same issue we have with SFC low-res screens -- they're 256 x 224. All the old 'CRT games' (saving Taito's double screen games and whatnot) are 4 : 3 (or 3 : 4). I'm not too anal with aspect ratio stuff for my screenshots as the Site shows, though, I just get close enough to it.

The real question here actually is -- how do we simulate the interlace of a high res mode like the SFC's?




Another thing is PC88 games (and several other computer games I'm sure) that run at different weird resolutions, and with different aspect ratios it seems:

http://www.soundshock.se/dump/WER1.png

Is that Wer Dragon?

See, that's what I meant. All the CRT games have a 4 : 3 aspect ratio. It just happens that many of them have also black borders, but those are also part of the screenshot itself. You'll find all the interweb emulator screens from PC88 and PC98 games at 640 x 400, but the actual hardware always left two black borders for a 640 x 480 full-screen resolution. So when you find this, for instance (PC98 Digan no Maseki):

http://i41.tinypic.com/nr0f88.png


...you actually should be editing it in order to get this:

http://i44.tinypic.com/fjjcwm.png


Your proof, in case:

http://i41.tinypic.com/24zlvvb.jpg




Some tips and comments would be very much appreciateed.

Forget this size and try ~ 1280 x 960 screens for everything. You can see Ronan's uploads are the way to go. Hi-res screens would get scanlines too at that size, but half their usual size (we still need to test that out). If you're using 640 x 480 screenshots despite my advice, be extremely careful with PC88 / PC98 games. They usually have default fake scanlines or other artifacts which don't allow for slight scaling / curvature or even blur without ruining the screen (that Wer Dragon screen, for example).

32

Re: Low-res screenshots

Recap escribió:

640 x 480 is a pretty bad size for low-res screenshot purposes.

Maybe it's a stupid question, but how come? I don't understand the theory behind this. Is it because image editing method's distortion is too obvious with such small resolutions?

What confuses me though is games that run at custom resolutions (like SFC Prince of Persia or certain cinematics, which run at 512*448 - should I resize that to 597 x 448?):

http://www.soundshock.se/dump/POP_SF3.png

Recap escribió:

Well, I'm not really sure that SFC POP runs at the system's high res mode (Are you? How?)

Hmm, scratch that. I forgot I had doubled the resolution already in the emulator settings.

So what's the procedure when creating these larger CRT simulations? Just to follow Ronan's instructions?
Should I start with the game's native resolution, no double, filter or scanline options?

Shit this is confusing. One thing I don't understand is why emulators aren't set to emulating the 4:3 aspect ratio by default? I mean the difference is huge!


Recap escribió:

Is that Wer Dragon?

It is.

Recap escribió:

See, that's what I meant. All the CRT games have a 4 : 3 aspect ratio. It just happens that many of them have also black borders, but those are also part of the screenshot itself. You'll find all the interweb emulator screens from PC88 and PC98 games at 640 x 400, but the actual hardware always left two black borders for a 640 x 480 full-screen resolution. So when you find this, for instance (PC98 Digan no Maseki):

Ah, that's why I got weird results with that intro sequence in that SFC System Sacom car game? The emulator removes the borders for us?

Recap escribió:

Forget this size and try ~ 1280 x 960 screens for everything. You can see Ronan's uploads are the way to go. Hi-res screens would get scanlines too at that size, but half their usual size (we still need to test that out). If you're using 640 x 480 screenshots despite my advice, be extremely careful with PC88 / PC98 games. They usually have default fake scanlines or other artifacts which don't allow for slight scaling / curvature or even blur without ruining the screen (that Wer Dragon screen, for example).

The emulators have default scanlines you mean, there must be some way to disable them though? I haven't the deciphered the options menu in M88 yet.

One more thing: when resizing these images to fit my website's design, is there something to keep in mind? All images will ofcourse link to the full-size version, but I'm sure there's a golden rule to make them look acceptable when scaled down?

Sorry for all the confusion...

33

Re: Low-res screenshots

Ok, I'm trying Ronan's 4 x method now. Irfan and GIMP lacks a bilinear resize option (there's cubic, linear and sinc) though? What are you guys using?

34 (editado por Ronan 11-04-2010 17:57:03)

Re: Low-res screenshots

Oh, right, I used linear. Bilinear basically means linear in two dimensions.

35

Re: Low-res screenshots

Ah, okay:

http://soundshock.se/dump/TEST1.png

36

Re: Low-res screenshots

Strange. The PNG for the scanline effect has an alpha layer (i.e. transparency), but it seems that you don't use it... Can you check this? If you don't manage to do it, I will create two PNGs without alpha layer. That should work fine.

Could you send the original screenshot?

37

Re: Low-res screenshots

Uh, come again? You mean 4xnewezter.png has an alpha layer that I somehow should make use of? I'm sorry but I'm not used to these terms.

http://soundshock.se/dump/TEST2.png

http://www.soundshock.se/dump/test1.bmp
http://www.soundshock.se/dump/test2.bmp

38 (editado por Ronan 11-04-2010 20:15:33)

Re: Low-res screenshots

Well, it is just that your screenshot looked strange, so I wondered what could have gone wrong. Since the PNG I linked has some transparency, I thought that maybe your software didn't take this into account. I checked, and that seems to be the case, for whatever reason...

Anyway, I have just made two new PNGs, without any transparency, that should do the job. Use the same procedure as exposed above, but copy the first PNG below in the layer in Overlay mode, and the second in the layer in Multiply mode:
http://img687.imageshack.us/img687/6259 … aoverl.png
http://img208.imageshack.us/img208/3949 … amulti.png

You should get something like this:
http://img217.imageshack.us/img217/9649/test2a.png

39

Re: Low-res screenshots

zinger escribió:
Recap escribió:

640 x 480 is a pretty bad size for low-res screenshot purposes.

Maybe it's a stupid question, but how come? I don't understand the theory behind this. Is it because image editing method's distortion is too obvious with such small resolutions?

The theory behind it is just that the bigger the size, the bigger the ability to mimic true scanlines' behaviour in a digital environment is. Keep in mind that true scanlines aren't perfectly regular black lines; they vary according to the colors they separate, being even virtually invisible with some colors like red if the screen is not too big:

http://i47.tinypic.com/acto21.jpg

In order to simulate the lines' 'melting', or getting closer to it--since that's still to properly simulate--we need a bigger resolution. Just compare Ronan's samples with any of Postback's screens. Of course, going further, if the size is big enough we could even work in a per-pixel basis for even more accuracy.




Shit this is confusing. One thing I don't understand is why emulators aren't set to emulating the 4:3 aspect ratio by default? I mean the difference is huge!

You'll soon get used to it. It's easy to understand why the emus' settings aren't 4 : 3 by default -- they're emulators, not simulators. Ideally, we all should be using video hardware capable of the original systems' video modes, so no artifacts of any kind would be needed.




Recap escribió:

See, that's what I meant. All the CRT games have a 4 : 3 aspect ratio. It just happens that many of them have also black borders, but those are also part of the screenshot itself. You'll find all the interweb emulator screens from PC88 and PC98 games at 640 x 400, but the actual systems' frame buffer left two black borders for a 640 x 480 full-screen resolution. So when you find this, for instance (PC98 Digan no Maseki):

Ah, that's why I got weird results with that intro sequence in that SFC System Sacom car game? The emulator removes the borders for us?

Which "weird results"? "The emulator" removes the borders only if you tell it to do so. With a standard SFC game, you have natively 256 x 224. That's usually doubled for default non-windowed display with SFC emus. Given that 512 x 448 is less than VGA mode res (640 x 480), you get borders. If you want to get true full-screen, you need the emu or the video card to scale it to that res. It's an anisotropic, non integer scaling, so any pre-scaling effect will be affected and indeed the pixels are distorted.



Recap escribió:

Forget this size and try ~ 1280 x 960 screens for everything. You can see Ronan's uploads are the way to go. Hi-res screens would get scanlines too at that size, but half their usual size (we still need to test that out). If you're using 640 x 480 screenshots despite my advice, be extremely careful with PC88 / PC98 games. They usually have default fake scanlines or other artifacts which don't allow for slight scaling / curvature or even blur without ruining the screen (that Wer Dragon screen, for example).

The emulators have default scanlines you mean, there must be some way to disable them though? I haven't the deciphered the options menu in M88 yet.

Nope, I meant the game's default fake scanlines. This is material for the second part of my scanlines essay, so without elaborating it too much, many games for the old Japanese computers were designed with fake scanlines in order to prevent the always ugly line-double effect, given that they used graphics designed in low res for RAM and budget limitations.

So when you have something like this:

http://fullmotionvideo.free.fr/screen/z/tori1.png
PC98 TRITORN II

...it's normally because the game was indeed designed so and not an emulation artifact, unlike, say, MAME's.

(And there you have who's the actual inventor of that thing so popular these days as is the fake scanlines. Not many people know that!)




One more thing: when resizing these images to fit my website's design, is there something to keep in mind? All images will ofcourse link to the full-size version, but I'm sure there's a golden rule to make them look acceptable when scaled down?

I'd need to know the thumbnails' size in order to answer this, but unfortunately I don't think there'll be a very good way for non-photographs. Best way I can think of is taking the original, non-scaled screen (or just scaled to 4 : 3), adding curvature, blurring it a bit and touching up the colors if needed with IR Fan View.

40

Re: Low-res screenshots

I made an attempt with Metal Slug, but it doesn't look quite the same.

http://fc27ya.blu.livefilestore.com/y1p … RQYuoYEB5i

I'm guessing that either the scaling is different (chose Bilinear for this), or the overlay doesn't seem to get applied in the same way.

41

Re: Low-res screenshots

As far as I understand the subject, the bilinear interpolation should be equivalent no matter what software you use...

I am not sure about what is wrong in your picture. In fact, I still have some issues with PNGs and I am not sure that I see your image on my computer as intended.

Anyway, the "scanline effect" created by the layer in Overlay mode seems a bit overdone... If that is the problem, you could try to decrease the opacity of this layer...

42 (editado por Eboshidori 01-07-2010 16:32:04)

Re: Low-res screenshots

Hello low-res lovers !

First, I'd like to congratulate Recap about this excellent website.
Few years ago, the very first thing that took my attention was the care for the screenshots, a huge difference between every other sites with the usual jaggy or blurry pictures. Then I read the reviews and others stuff, and definitly I knew I was in the good place.

I've been working on the subject for long time, looking for the perfect scanline ( right after "the perfect beat" :-P ). I've been working on many different CRT, taking tones of pictures, understanding the complex way to properly set-up those screens. The goal was to be sure of what is possible and/or desirable to recreate with a raw output from an emulator. I'm still working on a huge tutorial about the set-up of CRT, especially the difficult part of convergence.

Many people in the emulation scene wants to recreate the feel of the CRT, but they have in mind that the picture tube gives "genuine" dirty visual, with lots of defects. They focus on the bad points (not on the right behavior of the beam under the best conditions). I can't stand this, because I'm an ardent supporter CRT precisely because this technology gives you the best picture at any resolution, if you feed it with a good signal. For example, take a look at those beautiful pictures of KOF XII sprites at their native resolution (640x360) on a Trinitron PC monitor:

http://raster.effect.free.fr/31khz/KOF_ … 66x768.jpg

http://raster.effect.free.fr/31khz/KOF_ … 360p_s.jpg

http://raster.effect.free.fr/31khz/KOF_ … 60p_2s.jpg

(others: http://raster.effect.free.fr/31khz/KOF_sprites_360p/ )

If only you could see it in front of the monitor, it looks georgeous. Very "15kHz-like", very "video game graphics". The deep black with the perfect colors of the tube give you an unmatched result. I can't have enough of the scanline effect. ^_^
And on this subject, I must say that Ronan has achieved the best result to recreate those beloved scanlines. His method is even better than mine, because it shows the behaviour of the beam at any greyscale. My method is more precise and "tweakable", but if I want to handle all greyscales, it becomes very laborious. His method is really simple compare to mine. So, nice job, Ronan. "You're doing great !" :-)

By now, I'm working with the wonderfull "soft15kHz" software that allows you to drive your graphic card at 15 kHz, with every possible resolution in this frequency, progressive and interlaced. Fuckin'great, I'm like a little boy in a big toy store. :-P
Very helpfull for working on non square pixel (like 448x224 or 512x240).


Before I log out, just for the pleasure, a full shot of a 15 kHz picture (Trinitron, low curvature):

http://raster.effect.free.fr/tv/photos_ … -Leo_s.jpg


See ya'

43

Re: Low-res screenshots

Welcome, Eboshidori. And thanks for the kind words. I hear you on the KOF XII subject. I'm still to see how the game works with the system set at 480p and a 31-kHz monitor, though it can't do the background graphics any good, so I'm not holding my breath. What a waste...

We have here a 'true low-res through your PC' thread [ > ] where we go a step further than most people and also explain how to get the card to run at the proper refresh rate for every particular game. If you happen to have an Arcade VGA / old ATI card and haven't gone through the issue yet, you have there an interesting read.

And yeah; that Leo screenshot is quite a pleasure for the eyes. I think it's people like you the ones who are going to enjoy the next Postback update the most. I talked with Ronan about asking you how to properly photograph a CRT, since it seems it's a matter you have lots of experience with. I've learned some bits since that Willow screen I linked in a previous post here and I'm more satisfied with my results every day, but maybe you still could show me some tips for the camera. My Trinitron is 'high curvature', though, making the screenshots less... 'consistent' around the corners. If you agree, we could follow the conversation in the development subforum.

44 (editado por Eboshidori 04-07-2010 18:25:30)

Re: Low-res screenshots

Recap escribió:

I hear you on the KOF XII subject. I'm still to see how the game works with the system set at 480p and a 31-kHz monitor, though it can't do the background graphics any good, so I'm not holding my breath. What a waste...

Most multi-sync/31 kHz arcade monitor have the same large pitch as usual TVs driven at 15kHz. That means you can't obtain such precise scanline (as on the picture shown before) at 31 kHz on these.
The electron gun is conceived for bright and large beam spot, and you have limited number of phosphore triads. You need a 21 or 22" PC monitor with thin electron gun and precise grid (but small screen size...) or an insanely expensive 32" CRT Broadcast monitor that can really display 720p.  You can also have good results with CRT projectors (but not as good as direct view CRT).

I don't own an Xbox 360, but I'm pretty sure that the downscaling to 480p is filtred. Anyway, even if it's not as precise as the picture posted above, it will alway be more pleasant to the eye than rough cubic pixels at different resolution of the background, and of course blurry filtred sprites.

This picture [>] is based on a nice .png screenshot of KOF XII (720p), reduced to 360p with nearest neighbor option. Perfect pixel for the sprites and the background, displayed in heavenly conditions on a performant CRT. Each time I look at this, and then go to see the game on 768p or 1080p flat screen (because there are very few true 720p flat pannels out there...), I'm so angry. I just want to take a hammer and smash the screen. :P

Considering that KOF XIII only runs with filtred sprites upscaled at 150%, there's definitly no chance to try any tricks to display a nice picture on the best CRT displays.

Just for the tears:

http://raster.effect.free.fr/tv/photos_ … s_comp.jpg

> Part of a 720p KOF XIII screenshot on the same Trinitron monitor, driven at 31 kHz. On the left, a native res' sprite of Iori, and on the right, the sprite with 150% filtred upscaling.
:-[


Even if you take the signal and converted it from 720p to 852x480 (a 66% downscaling in order to recover the original size of the sprites and have the same definition between background and sprites), it's impossible to obtain the same precision and gorgeous visuals as the KOF XII 360p picture.


Men, I hate fixed res' pannels, and I hate the "everything scaled and filtred" shit.

What's the point to have easily adressable pixels (the only advantage compare to CRT) if most time you get blurry picture and artifacts ? Flat pannels are just good for internet browsing and word processing. For everything else, you need true multi-sync monitor. And CRT is the only technology that can gives you this.



We have here a 'true low-res through your PC' thread [ > ] where we go a step further than most people and also explain how to get the card to run at the proper refresh rate for every particular game. If you happen to have an Arcade VGA / old ATI card and haven't gone through the issue yet, you have there an interesting read.

Yeah, I suspected you would already know the software ^^, or have tried an arcade VGA or something else.
I knew there were solutions to drive a graphic card at 15 kHz, but for many years I didn't want to hear anything from PC stuff and emulators. I was fed up with, and went to original hardware: nice CRTs, real consoles and arcade PCBs.

The reason I finaly try soft15khz few day ago was the creation of the best patterns for convergence and geometry adjustement.

You can check this:

http://raster.effect.free.fr/15khz/CRT_set-up/mires_240p/mires_240p_conv_cross_R+B+M_v6_centre.png

(others: http://raster.effect.free.fr/15khz/CRT_set-up/ )

Very useful, and much more efficient than any stuff you can find in PCB service menu, or any regular convergence pattern available.



I think it's people like you the ones who are going to enjoy the next Postback update the most. I talked with Ronan about asking you how to properly photograph a CRT, since it seems it's a matter you have lots of experience with. I've learned some bits since that Willow screen I linked in a previous post here and I'm more satisfied with my results every day, but maybe you still could show me some tips for the camera. My Trinitron is 'high curvature', though, making the screenshots less... 'consistent' around the corners. If you agree, we could follow the conversation in the development subforum.

Without modesty, I can say that I'm the expert of CRT photographing. :P
With my advices, you will achieve such quality  as this :

http://raster.effect.free.fr/tv/photos_ … G-SvsC.jpg
(it's reduced at 50%, the original picture is much precise, but very big, about 5 MB)

Near perfection CRT set-up and proper way to capture it with your camera.

This is the best you can obtain from a curvated shadow mask picture tube at 15 kHz. The beam spot is precise at every greyscale, even on bright red.
And about the matter of the red beam:

Keep in mind that true scanlines aren't perfectly regular black lines; they vary according to the colors they separate, being even virtually invisible with some colors like red if the screen is not too big

The red beam is alway driven stronger than the green and blue (because red phosphore is less efficient and needs more current), but with a proper set-up of every parameters, you can obtain precision at all levels.
So, the usual blur and merging that occur with bright red portions are not a characteristic of the CRT picture, it's just a question of the quality of the adjustment. Hence, we see that carefull observation is not enough, you need to know the way to set-up a CRT to determine what to do for recreating a CRT picture in digital environement.


Most TVs and arcade monitors are not set-up to their maximum possibility (especially for convergence), because you need time to do it, and because 15 kHz screen are primarily conceived for bright picture (for use in bright environment) and interlaced signal, with a necessary melting of lines. Precision is not the main goal for 15 kHz interlaced picture tube. But we, pixels lovers and users of non-interlaced signals, we want it, because it's possible !!! :P

Lots of people think that each field of the interlaced signal ("half picture", at half the resolution) is supposed to be displayed with a large space between the lines in order to fit the lines of the next field. That leads to think that "scanlines" are plain black lines with the same size of the line displayed. Hey no ! First, scanlines are the lines that are displayed (that are... scanned), and the black space between them is not regular, not as large. But for convenient sake, people continue to call "scanlines" the black space they see in 15 Khz picture, and they continue to view it as regular lines. It's difficult for them to understand why the beam vary in size. But this is nothing less than the fundamental part of the CRT technology, and the most important thing to achieve a good CRT simulation. But when you see some atrocity like this:

http://www.bogost.com/games/a_televisio … ator.shtml

Then, you know that people are very far from understanding the point...


I've been working on a way to easily recreate the variation of the beam:

http://raster.effect.free.fr/15khz/samples/x4_L_std.png
(example of a bright pixel)


http://raster.effect.free.fr/15khz/samples/x4_D_std.png
(example of a dark pixel)


Even if in reality, the spot would have different sizes, for digital environment, I choose to use the same size and create the illusion with shades of colors.
A pixel that would have been a 4x4 square in a classic 400% nearest neighbor scaling becomes a 6x4 sample (the core is 4x4, and you have two extra columns depending if the beam size increases of decreases).


The goal is to "interpret" the picture in only one pass (to have minimum use of resources and minimum lag), directly taking each original pixel and "construct" the final result according to a table that store small sets of values ( 1A to 4F in the examples above) for every variations of greyscale. There would be only one comparison with each previous pixel per line, to determine if the beam increases or decreases. Well, it's a simulated scanning (from top to bottom and left to right) to obtain the data, but the result is made of a full frame (no layers, no transparencies), constructed for fixed resolution.
It may not be very clear, because it's not so easy to explain it in french even for me... ^^
But I think this is the best way. The difficult part is to create the table, you need a perfect screenshot to start from. For this, I will use my method, because it's very tweakable and precise. I need to adust every layer according to the observation of the behavior of the real beam in the best condition : the proper set-up of the screen. For this last point, I'm ready now, I know. :-P

I need to explain the trick and convince somebody to write a bunch of code lines, somebody who wants to recreate a perfect CRT picture, not somebody who think that CRT screens produce genuine dirty pictures with lot of defects that you need to focus on. In fact, that's the tricky part ! ^_^

So, wait and see...

45

Re: Low-res screenshots

Eboshidori escribió:
Recap escribió:

I hear you on the KOF XII subject. I'm still to see how the game works with the system set at 480p and a 31-kHz monitor, though it can't do the background graphics any good, so I'm not holding my breath. What a waste...

Most multi-sync/31 kHz arcade monitor have the same large pitch as usual TVs driven at 15kHz. That means you can't obtain such precise scanline (as on the picture shown before) at 31 kHz on these.
The electron gun is conceived for bright and large beam spot, and you have limited number of phosphore triads. You need a 21 or 22" PC monitor with thin electron gun and precise grid (but small screen size...) or an insanely expensive 32" CRT Broadcast monitor that can really display 720p.  You can also have good results with CRT projectors (but not as good as direct view CRT).

I don't own an Xbox 360, but I'm pretty sure that the downscaling to 480p is filtred. Anyway, even if it's not as precise as the picture posted above, it will alway be more pleasant to the eye than rough cubic pixels at different resolution of the background, and of course blurry filtred sprites.

And more importantly, you can play the game that way since the system (either, the 3-60 or the Type X 2) does support 480p. Your samples are great and necessary for showing everybody that KOF XII's graphics are ruined by lame design decisions and a full-of-shit technology, and hopefully you'll create with them some short of a virtual museum in order to let the internet see and take notes, but... just that.





This picture [>] is based on a nice .png screenshot of KOF XII (720p), reduced to 360p with nearest neighbor option. Perfect pixel for the sprites and the background, displayed in heavenly conditions on a performant CRT. Each time I look at this, and then go to see the game on 768p or 1080p flat screen (because there are very few true 720p flat pannels out there...),

I do really wonder if there's not a true 768-lines mode on this game. Blaz Blue has it, and Type X 2's most common mode is WXGA, given the arcade monitor standards.




Considering that KOF XIII only runs with filtred sprites upscaled at 150%, there's definitly no chance to try any tricks to display a nice picture on the best CRT displays.

I'm sure there'll be an option to remove the filter (at least for home versions), but in the end, same issue as in XII -- you can't play the game and please your eyes at the same time.




Men, I hate fixed res' pannels, and I hate the "everything scaled and filtred" shit.

What's the point to have easily adressable pixels (the only advantage compare to CRT) if most time you get blurry picture and artifacts ? Flat pannels are just good for internet browsing and word processing. For everything else, you need true multi-sync monitor. And CRT is the only technology that can gives you this.

It's called 'the brainless syndrome of our masses' and it's the same reason why handhelds have taken over proper systems, to name just one. Rhetorical answer for a rhetorical question, I know.





Without modesty, I can say that I'm the expert of CRT photographing. :P
With my advices, you will achieve such quality  as this :

Fine then. Moving this part of the conversation to the development subforum then.




Keep in mind that true scanlines aren't perfectly regular black lines; they vary according to the colors they separate, being even virtually invisible with some colors like red if the screen is not too big

The red beam is alway driven stronger than the green and blue (because red phosphore is less efficient and needs more current), but with a proper set-up of every parameters, you can obtain precision at all levels.
So, the usual blur and merging that occur with bright red portions are not a characteristic of the CRT picture, it's just a question of the quality of the adjustment. Hence, we see that carefull observation is not enough, you need to know the way to set-up a CRT to determine what to do for recreating a CRT picture in digital environement.

The truth is that I love the slight 'melting' with bright red lines and whatnot. I'm so used to it that I like to think of it as a particularity of CRT displays (and indeed I miss it in your photographs). But I can understand that, while it may help the overall visual enjoyment depending on your tastes, it goes against pure 'pixel analysis', yeah.






The goal is to "interpret" the picture in only one pass (to have minimum use of resources and minimum lag), directly taking each original pixel and "construct" the final result according to a table that store small sets of values ( 1A to 4F in the examples above) for every variations of greyscale. There would be only one comparison with each previous pixel per line, to determine if the beam increases or decreases. Well, it's a simulated scanning (from top to bottom and left to right) to obtain the data, but the result is made of a full frame (no layers, no transparencies), constructed for fixed resolution.
It may not be very clear, because it's not so easy to explain it in french even for me... ^^
But I think this is the best way. The difficult part is to create the table, you need a perfect screenshot to start from. For this, I will use my method, because it's very tweakable and precise. I need to adust every layer according to the observation of the behavior of the real beam in the best condition : the proper set-up of the screen. For this last point, I'm ready now, I know. :-P

I need to explain the trick and convince somebody to write a bunch of code lines, somebody who wants to recreate a perfect CRT picture, not somebody who think that CRT screens produce genuine dirty pictures with lot of defects that you need to focus on. In fact, that's the tricky part ! ^_^

So, wait and see...

Looking forward to it, though you need too big resolutions for that and you know web design requirements... Nevertheless, your ultimate goal is solving to some degree the emulation-related issue, isn't it?

46 (editado por Recap 06-07-2010 22:51:12)

Re: Low-res screenshots

Moving this here from the development subforum since I guess it will be of interest for non-contributors too:

Macaw escribió:

Just messing around here a bit. These are some direct screen captures using the emulator. They end up as 640x400, and I've taken one both with and without m88's scanline option. I still have no idea how stuff really should look on a real pc88, so I'll let you analyze it a bit. I'll mess around with m88's options more over time.

In the low res screenshots thread you also mention how some games such as Tritorn 2 were designed with fake scanlines. Are you sure you weren't just fooled by the m88 scanline option? In the first shot of Dios here with the m88 scanline option off you can see that there are no lines at all, though perhaps Dios wasn't designed with fake scanlines?
Perhaps I've completely misunderstood you in the first place, I still don't know much of the technicalities in this area but would appreciate learning more.

http://img9.imageshack.us/img9/1986/dios1.png http://img267.imageshack.us/img267/707/dios2.png

Old-computer screenshots is indeed quite a tricky subject. Most of them from 1983 onwards--PC88 included--supported both, 15 kHz (low res) and 31 kHz (hi res) modes. For PC88 and PC98, almost always you'd find either, 640 x 200 or 640 x 400 (they were actually 640 x 240 and 640 x 480 once the monitors' benchmarks were set as I explained earlier, but let's just leave that apart for now). PC88's hi-res mode was pretty limited color-wise, so we must assume most games used 640 x 200. So an actual frame-buffer screen from your game should be like this:

http://i50.tinypic.com/1qnwb5.png

By that (which I guess it's the first PC88 screen ever at its original resolution [laughs]), you can understand why the emulator--conceived, sadly, only for stardard PC video cards--automatically line-doubles the image (1st screen in your post) -- the aspect ratio through a standard PC is way too distorted. The game, you know, despite the resolution, had a 4 : 3 aspect ratio (not really 4 : 3 if we count the excluded borders, but close enough). It could be possible--I never had a PC88--that the game was line-doubled on the original frame-buffer for a 'fake' hi-res display so that the emulator is actually mimicking that behaviour, but given that there also existed 15 kHz-only PC88 monitors, I don't find that too plausible. That's also the reason for a universal scanlines simulation feature on the emulator (your 2nd screen) -- it's the most natural way to replicate the original low-res display on hi-res video hardware (therefore rendering the line-double method quite useless), though we've already explained that the final result here--no matter the type of monitor you're using--lacks the beauty of actual 'scanlines' for several reasons (hence the point I've been claiming for years of never using a standard PC for proper emulaton, if you're really into that).

Now PC98 is a bit different. It was especially designed for hi-res (most of its monitors indeed couldn't do 15 kHz) and we must assume that most games were rendered at 640 x 400. This was a problem for simultaneous PC88/PC98 releases or PC88 - PC98 ports -- you now needed to double the original lines for a hi-res display, and that's what many devs did:

http://fullmotionvideo.free.fr/screen/m/xak1.png
PC98 Xak

http://www.rpg.bajtnet.pl/pc98/fray_j/wid.png
PC98 Fray

(They didn't need any excuse though -- many original PC98 games were also designed at half the display resolution, saving RAM demands and well, effort.)

Fortunately others decided against this awful method and invented the scanlines simulation -- instead of drawing the same line twice, even lines would be black lines. That PC98 Tritorn II screenshot you mention, to answer your question, doesn't have scanlines added by the emulator; the game was rendered exactly so. You can check these other examples for more color:

http://fullmotionvideo.free.fr/screen/p/lesser1.png
PC98 Lessern Mern

http://fullmotionvideo.free.fr/screen/g/vd21.png
PC98 Vain Dream II


Notice the scanlines are applied only in the action area or the background -- there's no way an emulator could do that. Of course they went even further and invented different patterns which, applied on the line-doubled picture, would alleviate the issues of design - display discrepancies:

http://fullmotionvideo.free.fr/screen/a/digan%201.png
PC98 Digan no Maseki

So that's why you won't find (my guess) a scanlines simulation feature on any PC98 emulator.

This pretty much covers, not just your questions, but the whole core of what was going to be part 2 of the Scanlines -- Ab Initio article, so it's now done for anyone's interested. Thank Macaw. The only remaining thing would be illustrating with actual photographs the wonders of 15-kHz CRTs to let everybody see what they've missed, and that will come with the new Site's content itself. So yeah.



Edit: Grammar bits.

47

Re: Low-res screenshots

Fabulous post Recap.

The partial scanlines thing is something I have always wondered about in PC98 games. Do you know if it provided any extra performance on games? Its insane that stuff such as Vain Dream 2 and Digan would have the character sprites designed properly in high res, then apply the scanline technique to the backgrounds. It would have been frustrating trying to design the backgrounds to properly fit the scale of the sprites, and the background tiles really aren't that complex so why not just design those properly for high res too.

Anyway, in the case of most PC88 stuff and some of the 98 stuff, Its incredibly bizarre that they had to design stuff in 640x200, knowing that the height will be doubled.

Lets just look at that 640x200 Dios shot you have there, so those are what the original graphic elements look like once designed. So in the case of Dios for example they wanted a realistic proportions look on the characters, yet had to originally design them to be quite wide. It would have been hard to know what a game would end up looking like if your designing stuff originally in a different scale. Companies designing these games at the time would have had to do constant double width mock ups to see what stuff is looking like, or perhaps even design stuff in the double length initially and then cut it back down to half.

48

Re: Low-res screenshots

It's quite unique, at least. Needs some corrections once I get the time to check the Japanese interweb. For instance, I've learned that the 640 x 400 mode of these is not 31 kHz, but 24 kHz. That technically is not 'high resolution', but 'extended resolution', as some put it. But pretty much it's all like I pictured.


Macaw escribió:

The partial scanlines thing is something I have always wondered about in PC98 games. Do you know if it provided any extra performance on games? Its insane that stuff such as Vain Dream 2 and Digan would have the character sprites designed properly in high res, then apply the scanline technique to the backgrounds. It would have been frustrating trying to design the backgrounds to properly fit the scale of the sprites, and the background tiles really aren't that complex so why not just design those properly for high res too.

I disagree. The more the resolution, the more the details needed. Simple tiles would get complex unless you go with 'empty-style' backgrounds and 'flat' colors. Scanline effects just helped to avoid this style, which generally has little to do with the 8-bit style they were trying to evolve. And let's not forget about RAM and even CPU limitations -- in this sense, it indeed did provide 'extra performance' on games.



Anyway, in the case of most PC88 stuff and some of the 98 stuff, Its incredibly bizarre that they had to design stuff in 640x200, knowing that the height will be doubled.

Lets just look at that 640x200 Dios shot you have there, so those are what the original graphic elements look like once designed. So in the case of Dios for example they wanted a realistic proportions look on the characters, yet had to originally design them to be quite wide. It would have been hard to know what a game would end up looking like if your designing stuff originally in a different scale. Companies designing these games at the time would have had to do constant double width mock ups to see what stuff is looking like, or perhaps even design stuff in the double length initially and then cut it back down to half.

I hardly believe that they used square pixels-based video hardware in the early years to design game graphics. They most likely used hardware capable of the same video modes as the target platforms -- remember that work stations and PCs weren't always like they are today and that there was a era where the pixels' aspect ratio was indeed a quite changeable thing thanks to CRT technology.

49 (editado por Macaw 09-07-2010 20:08:56)

Re: Low-res screenshots

Recap escribió:

I hardly believe that they used square pixels-based video hardware in the early years to design game graphics. They most likely used hardware capable of the same video modes as the target platforms -- remember that work stations and PCs weren't always like they are today and that there was a era where the pixels' aspect ratio was indeed a quite changeable thing thanks to CRT technology.

This makes things make more sense then, though designing with pixels that had more height than width would have been quite unique.

A bunch of the Technopolis issues from 1989 I have feature pixel design articles towards the end. I should have a closer look at those eventually.

50

Re: Low-res screenshots

By chance, do you have any Technopolis mag where Tamashii no Mon is featured or advertised? I'm desperately looking for the cover art at decent resolution.

Pasting here the promised PC88 Dios screenshot at its native res with 15 kHz video hardware. This is how the game looked like originally on the PC88:

http://i30.tinypic.com/2v8k9oy.jpg

Notice, despite the blurry pic (I was out of luck this time), that it has little to do with what you get with standard PC video hardware. Graphics look almost like a 16-bit console game.