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CRT emulation provides authentic retro gaming

CRT emulation provides authentic retro gaming

Check out that realistic ghosting effect! (see what we've done there?)

While it’s easy enough to get emulation software for 8-bit computers and consoles, you’re never going to be able to relive the proper experience without a flimsy digital joystick and a CRT TV rather than a flashy LCD monitor. We’re not talking about the decent CRT technology found in last-generation TVs and monitors; we mean the Evil Edna-style box that you might have plugged into the RF socket of an Atari 2600 in 1982. However, researchers at the Georgia Institute of Technology reckon that they’ve managed to successfully emulate the quirks of a dodgy CRT on an LCD, in order to enable an authentic retro gaming experience.

Taking the Atari 2600 Stella emulator as their foundation, team of coders set about recreating the scanline patterns, ghosting effects and colour-bleed that the crustier gamers among us might remember from childhood Breakout sessions. Ian Bogost, who instigated the project, explains that “many of today's players may only experience Atari games in emulation. Indeed, many of my students may have little to no memory of CRT televisions at all. Given such factors, it seems even more important to improve the graphical accuracy of tools like Stella.”

Bogost says he gave a Tech Computer Science capstone group the task of modifying Stella to accurately simulate several effects associated with CRTs. These included noise from the RF signal, colour-bleed between scanlines and the edges of sprites, plus afterimage effects. Bogost describes the latter saying that it was the result of the phosphor glow, which he says “leaves more of an afterimage on the human retina compared to an LCD display. As a result, images might linger after they had moved or changed. Atari programmers took advantage of this feature to "flicker" objects between frames.”

As well as this, Bogost wanted Stella to emulate the “texture” of sprites seen on a CRT TV. He notes that “the display itself is not constructed out of pixels like a monitor, but out of the phosphorescent glow of an electron beam as it shines through a focusing grate. The result produces slightly separated coloured dots on the screen, which become less visible as the viewer moves away from the set.”

Anyone who regularly watches DVD movies on a CRT TV will know that compressed movies often appear to be much smoother and cleaner than they are on an LCD TV, simply because the CRT’s analogue nature smoothes out edges and hides compression. Similarly, old games will look much smoother on an old CRT TV than they will on a current PC monitor.

Bogost has some screenshots of Enduro, Pac-Man and Yars’ Revenge that demonstrate the CRT emulation in action, which you can see below. According to Bogost, the team is now working with the guys who maintain Stella to patch the CRT emulation changes into the build. Bogost also says that he’s “hopeful that this software might be extended for use in other emulators for computer systems that used televisions as their primary output.”

Although plenty of other emulators offer primitive CRT TV emulation, this is the first time we’ve seen a concerted effort to really reproduce the quirks of an old CRT TV on a modern computer. Are the effects of a CRT TV needed to fully appreciate retro games, or would you rather have the clean colours and pixels of an LCD? Which other emulators would you like to see using technology such as this? Let us know your thoughts in the forums.

Via The Register.

CRT emulation provides authentic retro gaming
Pac-Man - Note the afterimage effect on the flickering ghosts.

CRT emulation provides authentic retro gaming
Enduro - Bogost says that the bleeding between the multiple coloured lines in the sunset makes the sky more realistic.

CRT emulation provides authentic retro gaming
Yars' Revenge - The scanlines give the image a textured feel, rather than simple flat pixels.

24 Comments

Discuss in the forums Reply
Bauul 5th May 2009, 16:28 Quote
My primary TV is a 32 inch CRT for this very reason. SD inputs just look 10x better on a CRT with its natural AA than an LCD (especially without decent hardware upscaling) ever could. When I eventually move to HD, I'll pick up an HD TV, but until then you can't beat a good old CRT for the wonderful way they smooth the image (and provide deeper blacks etc. etc.).

True for a monitor it's LCD all the way, as a totally static pixel perfect image is important for things like text, but for TV, never been.
p3n 5th May 2009, 16:29 Quote
Looks like when im cooking with glasses on :>
EvilRusk 5th May 2009, 16:30 Quote
That's cool, but somehow it isn't going to simulate the effect of staring really closely at the CRT screen to see the red green and blue pixels individually...
Hustler 5th May 2009, 16:32 Quote
I dont care what anyone says, modern HD LCD TV's and monitors are crap for any kind of retro gaming....

Wish i'd kept my old 19' Mitsubishi Diamond Pro CRT from a few years ago, far better picture all round (blacks that actually look black, colour intensity) than any LCD i've seen.

No bother with running at anything other than the LCD's native resolution either....

And as for stuff like MAME,ZSNES..etc, the old games look far better on a CRT.

In fact the only advantage my LCD has over the CRT is the ability to go into portraight mode for vertical 2d shooters.
Joeymac 5th May 2009, 16:33 Quote
Is there a Youtube example clip for this? There must be... these aren't the dark ages.
GoodBytes 5th May 2009, 17:35 Quote
Quote:
Originally Posted by Hustler
I don't care what anyone says, modern HD LCD TV's and monitors are crap for any kind of retro gaming.....
I'll go as far as saying for anything for CRT computer monitors. Sure they are big and heavy. But it's the ONLY display (especially the high-end ones at the end of life of the CRT area (which cost a fraction of the price of an LCD) that have accurate color, maximum view angle, and support about all screen resolutions, no ghosting and all the problems of LCD technology.

I mean let's look at my 17inch and 19inch CRT monitor, both can go 1600x1200 @ 85Hz (no flickering at this level). My monitor cost 400$. You want the same thing in a LCD... well for one it does not exists, you need 2 of them minimum.. one for graphics and the other for movie/gaming. How much they are? Well the first one, 22inch is the closest resolution, is about 1500+$ US, and the second one is about 300$, if you are willing accept several drawbacks. So is for a grand total 1800$.
1800$ JUST to save a little desk space, which is lost because you have 2 monitors, and have the inconvenience of switching every time between 2 monitor, versus a 400$ high-end CRT monitor. To this date I think the LCD technology was a HUGE step back in end result in display. And I am SURE, that if CRT's still widely sold today, they would be thinner, lighter and even better thanks to newer technology, even go at higher Hz.. like 150Hz (when I do that on my CRT (800x600), it feels like looking at a sheet of paper)
Omnituens 5th May 2009, 18:58 Quote
I prefer my emu's with sharper image - i <3 pixels.
ZERO <ibis> 5th May 2009, 19:07 Quote
So are they going to make a converter box or something that lets me hook up my old systems and have them look like they did on the old tvs?
rembo666 5th May 2009, 19:50 Quote
Holy crap GoodBytes, where did you get those prices? I got a 22-inch LCD for like $230. Yeah color accuracy is bad, but it's much better on your eyes if you're working with text. I do just about everything on my main LCD monitor. I also have a 20" MultiSync CRT which I got for $20 on Craigslist. It has excellent color accuracy and it was probbably a $600 monitor when it was new, but it's only better for working with photos and such. Since I don't do much photo processing, I would trade that high-end CRT for a crappy LCD in a minute if I had the money for a second one.

P.S.

$1800, really? Where do you live?
MrMonroe 5th May 2009, 20:22 Quote
for the love of god, why?

why would you do this?
Cupboard 5th May 2009, 20:54 Quote
I agree with MrMonroe, I really can't see a use for this. It would be vaguely understandable if done by some bedroom coders but a university computer science department?
GoodBytes 5th May 2009, 21:36 Quote
Quote:
Originally Posted by rembo666
Holy crap GoodBytes, where did you get those prices? I got a 22-inch LCD for like $230. Yeah color accuracy is bad, but it's much better on your eyes if you're working with text. I do just about everything on my main LCD monitor. I also have a 20" MultiSync CRT which I got for $20 on Craigslist. It has excellent color accuracy and it was probbably a $600 monitor when it was new, but it's only better for working with photos and such. Since I don't do much photo processing, I would trade that high-end CRT for a crappy LCD in a minute if I had the money for a second one.

P.S.

$1800, really? Where do you live?

Prices are in Canadian, at the moment of purchase and currently checked.
My CRT was purchased 4-5 years ago, and now starting to show age (it's time has sadly passed form me, and obligated to get an LCD). My CRT was 600$, but price drop when the LCD was coming, and I got it for 400$. It's a NEC.
The LCD I was looking at is the only descent 22inch Samsung screen, meaning no glossy frame, or film and that is height adjustable. It has issues like about all Samsung's, backlit bleeding, 6-bit panel, uneven lit screen and poor color accuracy.

The 1500$ one is an EIZO screen, even backlit, 8-bit panel, proper color accuracy, but because it's not a TN panel, there is even ghosting or reverse gohsting when you move your mouse on the screen, so I don't want to know how it's going to look at when I watch a movie.

And it's not like I am looking at the best.

[rant]
If you can name me a screen 22 or 24inch that has decent level of color accuracy, 8-bit panel, no glossy frame nor glossy screen film, height adjustable, good quality/service, good for games/movies (not the best, just something good that won't show too much from normal distance) and no backlit bleeding... then I am all all ears.
But nooooooo, that doesn't exists, because people (that is what companies says) wants USB ports all around the screen, and 32-displays they can attach to it, and beg for ultra glossy screens made of the cheapest quality that the air itself scratches the plastic.

First make a descent display, THEN you can focus on these things, instead of recycling the same crap display for the last 2-3 years with a new design and added USB port and call it new. >:( Well as long as review sites don't notice and consumers don't as well, then why not, I guess, from a buisness point of view. Even Nvidia is not THAT bad. But I guess it hard things to catch as there are just so many displays out there.
[/rant]
The_Beast 6th May 2009, 00:47 Quote
I don't know why you would want to go back

CRT are great don't get me wrong (deep black, no ghosting...) but LCD are so light and convenient
LordPyrinc 6th May 2009, 02:37 Quote
Hum... let me see. Run emulation software to distort and otherwise crapify what was a good image? No thank you.
salesman 6th May 2009, 05:11 Quote
Good idea I like it.
/donecomment
mayhem 6th May 2009, 05:18 Quote
What wrong with old games on modern day Lcd screen. Lol i have both set ups i have modern day games on a 28" arcade monitor running between 15khz and 25khz and 1 now running on a 48 LCD. There is distinctive difference. No point slagging off one over the other because they are and all ways will be different. Any one can emulate any thing given time but it will never feel the same as all them years ago ... Why because we grow up ... We don't have the same feelings as when we were kids.
AstralWanderer 6th May 2009, 07:58 Quote
Quote:
Originally Posted by MrMonroe
for the love of god, why?

why would you do this?
(1) It provides a more accurate re-creation of older games and systems.

(2) The limitations of TV CRTs (not monitor CRTs in general, since these have advanced greatly) in many cases improved the image of low resolution (around 300 by 200 pixels) images. Try playing a classic game using CGA or MCGA in DOSBox or ScummVM - even with high quality scalers (hq3x) the sharpness provided by current LCDs makes many old games look like a depraved version of Tetris (gratuitous plug: GOG have the 1994 adventure game Beneath a Steel Sky available for free download - you just need to create an account to get it).

(3) Certain games (and computers for that matter) did, as noted in the article, make use of the quirks of TV displays - for example the Apple II made heavy use of quirks in the NTSC standard (discussed here). LCDs don't handle such features so emulation has to address them instead.
Star*Dagger 6th May 2009, 11:11 Quote
I remember lugging around my 21 inch CRT monitors, 70 lbs and up!
I always wondered if LCDs had the sharpness of crts, I have never done a side by side comparison. I was told by a monitor manufacturer that they could not make monitor grade glass in sizes above 21 inches, something about making the entire surface not bend light.

If I could get a 26 inch crt that weighs the same (or even 20% heavier) as my current LCD, I think i would go for it. I do think those days are over though, rip CRTS.

Cool to think that someone went to the effort of replicating the "errors" in the old games. I remember playing Yar's Revenge at my uncles house when i was a Kid. We are talking like 30 years ago, man.

My tastes now are EVE Online and TF2, and hopefully someone will come out with some Falcon 4.0 level complexity flight sims.

Yours in Big Screen Gaming Plasma,
Star¤Dagger
Sp! 6th May 2009, 12:05 Quote
having played arcade emu's on variouse pc monitors for a decade there's nothing that beats playing these games on my mame cab with a crt arcade monitor circa 1989....
GoodBytes 6th May 2009, 14:53 Quote
Quote:
Originally Posted by Star*Dagger
I remember lugging around my 21 inch CRT monitors, 70 lbs and up!
I always wondered if LCDs had the sharpness of crts, I have never done a side by side comparison. I was told by a monitor manufacturer that they could not make monitor grade glass in sizes above 21 inches, something about making the entire surface not bend light.

If I could get a 26 inch crt that weighs the same (or even 20% heavier) as my current LCD, I think i would go for it. I do think those days are over though, rip CRTS.

Sharpness of the image of a CRT depends on the quality of the CRT. One reason why CRT failed is because people were going to stores and went "Give me the cheapest computer monitor", so they get a terrible hard to read text screen, at 60Hz, that flickers and cause headache. In was in a time where the average computer users did not understand the concept of "you get what you paid for".
A good CRT will give you a very sharp image, and no flickering or headache.
CRT sizes exists in 32inch and even higher, I think I even saw 42inch CRT screen if I am not mistaken. Back in the old days, people were buying 27inch size screens, and that was considered large. 32inch was getting over the top. Something, thus, that you must remember, is that LCD screens are in widescreen. A 19inch LCD is much smaller in height then my 17inch CRT computer monitor.
ZERO <ibis> 6th May 2009, 21:47 Quote
I still use crts, I am down to two now and only one is what I consider a good one, being a Sony CDP-G520P and the other only being an accusync 90. I have had 3 16" sony trinitrons of the same model die out on me over the last 8 years. I have had my current sony for about 7 years and it still ticks along great. I move it 4 times a year along with what ever my secondary crt is on a 5 hour drive. I wish that there excited LCD screens that could match my primary crt but still I have yet to find one. Maybe those upcoming OLED monitors will be worth it....
NeedlesKane 30th September 2009, 07:06 Quote
my god im confused, we have a thread which shows crt emulation to make the picture worse and most of the comments are saying that crt quality is better. irony ftw. though plus 5 to CRT for displaying black better.
GoodBytes 30th September 2009, 07:25 Quote
Quote:
Originally Posted by NeedlesKane
my god im confused, we have a thread which shows crt emulation to make the picture worse and most of the comments are saying that crt quality is better. irony ftw. though plus 5 to CRT for displaying black better.
That's a emulation that does a very OLD CRT TV simulation. And a simulation doesn't do a good job than the real thing. In fact the idea of this emulation is to exactly look it bad for Atari games (early colored CRT TV's).

CRT TV's and computer monitor are completely different how they work. Computer monitor has 1 pixel (square) which has all the colors. TV are rectangles where it plays with the intensity of each color channel to output a color. CRT TV's even the latest good ones, is no wear a descent computer CRT monitor.

http://3.bp.blogspot.com/_lsW0D5f6cIA/SaTghI5s30I/AAAAAAAAAAk/e7Otip1mvds/s1600-R/you-are-being-monitored.jpg
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