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Atari Emulation of CRT Effects On LCDs 226

An anonymous reader writes "A group at Georgia Institute of Technology has developed a fun little open source program to emulate the CRT effects to make old Atari games look like they originally did when played on modern LCD's and digital displays. Things like color bleed, ghosting, noise, etc. are reproduced to give a more realistic appearance."


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Atari Emulation of CRT Effects On LCDs

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  • A program to make look CRT like teletype output (or DEC LA-36)??? Or to make CRT look like Hollerith cards???
    • Re: (Score:3, Interesting)

      by sdpuppy ( 898535 )
      What I want is one that can ply and look like Pong back in the good old days (all staticy with the screen jumping around when the numbers changed!)
  • by orospakr ( 715849 ) on Thursday April 30, 2009 @08:54PM (#27781749) Homepage

    What about the Apple ][ screensaver?

    http://www.jwz.org/xscreensaver/screenshots/ [jwz.org]

    I think it did something very similar.

    (hey, first post!)

    • by Sycraft-fu ( 314770 ) on Thursday April 30, 2009 @09:48PM (#27782199)

      One of the most widely used Blargg's NTSC libraries. Many console emulators make use of them. This new one just looks to be more advanced than most of the preceding ones.

    • The Apple screensaver is good. One of the Windows ports for MAME has excellent scanline emulation. At least on a high res CRT. It has a multitude of different patterns to choose from to best match the type of screen used on each game.

    • That's what I first thought of too.
    • The thing that blew my mind when I finally decided to look at the Analog TV code that the Apple ][ screensaver a couple others uses is that it's not just faking the effects, but it's actually simulating the real effects of interference, etc, on a picture tube. In other words, it simulates the operation of a CRT and what happens to the signal to cause the various effects we used to see in the Good Ol' Days.

      I definitely didn't understand it all, but it's a very cool and convincing effect.

  • Great use of tag (Score:4, Insightful)

    by RenHoek ( 101570 ) on Thursday April 30, 2009 @08:56PM (#27781765) Homepage

    I think this is one of the most justified uses of the 'brokenbydesign' tag ;)

  • by Anonymous Coward

    And does their program eliminate motion blur and the poor contrast of LCD to make it looks like a CRT?

    • by MobileTatsu-NJG ( 946591 ) on Thursday April 30, 2009 @09:24PM (#27781981)

      And does their program eliminate motion blur and the poor contrast of LCD to make it looks like a CRT?

      No but the 21st Century did.

  • But why!?!?!? (Score:4, Interesting)

    by xetovss ( 17621 ) on Thursday April 30, 2009 @09:02PM (#27781809) Journal

    And to think that it seems all the rage is to be upgrading Atari's with an Svideo board as featured on hack-a-day a few weeks ago http://hackaday.com/2009/04/05/s-video-from-an-atari-2600/ [hackaday.com] . Honestly I don't know why people want to make their TV's look like a 30 year old TV display. The reason for all that bleeding was the circuitry that converted the video and audio signal to RF and then the deconverting of that signal in the TV. It is beyond me why anybody would want to make something look like it did, instead of how it should look. I grew up playing the Atari 2600 and I thought it was fun, but I certainly am not fond of how it looked. I'm just waiting for my SVideo converter board to arrive so I can upgrade my 2600 to look how it should, not how it did. (And I'm still using a CRT TV as well none of these new fangled LCD TV's). - XSS

    • Re:But why!?!?!? (Score:5, Insightful)

      by Sycraft-fu ( 314770 ) on Thursday April 30, 2009 @09:36PM (#27782095)

      Because old systems counted on it. They were designed around working on low rez NTSC displays. You find that the color bleed and fringing and such helped smooth out the image and make it more natural. When you display it on a modern high resolution LCD it looks extremely blocky. So you emulate the problems with the older technology and you get a better looking picture for it.

      • Yeah, that was what I hated about upgrading to an LCD. I could notice imperfections that were previously "finessed" by the CRT. Sharp color dropoffs, granularity ... I thought something was wrong with my monitor at first!

    • Re:But why!?!?!? (Score:5, Informative)

      by Daniel_Staal ( 609844 ) <DStaal@usa.net> on Thursday April 30, 2009 @09:41PM (#27782145)

      Well, in the case of the Atari games, it is fairly obvious that the programmers used the effects to create nicer-looking graphics without going to extra work. Sort of a reverse anti-aliasing effect.

      Take a look at some of the comparison images in the article. The 'Enduro' image is particularly interesting: The skyline looks extremely fake on an LCD, but with the CRT emulation it looks almost realistic. The effect basically gives a continuous-color blend which would be impossible using just the colors available to the program.

      So really, you can argue that this is how the games were meant to be seen like this, and this is actually how it should look.

      • Re: (Score:2, Interesting)

        by hattig ( 47930 )

        The interesting thing comes with retro-game writers (who write games for the old machines, today) and the graphical styles of the games, which due to being designed and written in emulators on LCD monitors have changed. Old games used to stipple a lot to simulate shades of colours between what the hardware could actually achieve, whilst the newer games seem to have a more flat colour scheme - arguably this could be because the LCDs make the stippling look awful, whereas the CRT would make it look blended.

    • Re:But why!?!?!? (Score:5, Insightful)

      by fractoid ( 1076465 ) on Thursday April 30, 2009 @10:12PM (#27782407) Homepage

      It is beyond me why anybody would want to make something look like it did, instead of how it should look.

      But this IS how it "should look". It was designed for that display. People want it to look like it originally did for the same reason that people like muscle cars, vinyl records (complete with the hiss and wow and flutter that they try so hard to eliminate), valve amplifiers. It's because sometimes the inaccuracies in equipment change the signal for the better, and people like that.

    • I've played Atari games natively on a color TV set, as well as emulated on a SVGA CRT. I like it both ways. You get a super-clear picture on the computer monitor, but it's nostalgic to play it with the video artifacts that came from the RF input and NTSC. If you value a true historical re-enactment, you kindof need to be able to do this. It's something that you can configure to your preference, so having it as an option doesn't hurt anybody. Even MegaMan 9 had a special mode that allowed you to emulate

    • Re: (Score:3, Informative)

      by bonch ( 38532 )

      This page [slack.net] has screenshots showing the difference. Many games were designed with NTSC artifacts in mind.

    • by hawk ( 1151 )

      That's a few steps ahead of me.

      I'm still trying to figure out whether I can simply connect the video cable to the input rather than the output of the RF modulator. I have a 2600 with about 30 cartridges waiting to fire back up . . . hmm, and how will I get the sound out, given that the only input I have on these things are separate R/L/V connections?

      And while we're at it on apple's, I want a pre-rev 7 emulator for the ][, so that I get the purplish tint (Rev 7 killed the color subcarier in text mode). Hmm

  • NTCS filters (Score:3, Insightful)

    by Ailure ( 853833 ) on Thursday April 30, 2009 @09:03PM (#27781819) Homepage
    Reminds me about the various NTSC filters used in various emulators (such as Nestopia). It's kind of funny how some people strive for simulating the original display, but I have to admit that I personally use the NTSC filter when possible. (and I avoid using filters like super eagle which have a tendency to make stuff look like blobs...)
  • Overdid it. (Score:3, Insightful)

    by nausea_malvarma ( 1544887 ) on Thursday April 30, 2009 @09:04PM (#27781827)
    The effect is great in theory, but I think they over did it. Old arcade games are certainly a bit blurry, and have some ghosting issues, but this effect makes every little sprite into a pile of fuzzy crap. It's too bad to be true, and it ends up looking fake. Reminds me of those pre-faded jeans, with so much added wear that its easy to tell the wear and tear is not natural. Instead of looking like a pair of old jeans, they look like a pair of new jeans that someone split bleach on. Like these [magickidsusa.com]
    • by Toonol ( 1057698 )
      Yeah, this isn't a CRT emulator. This is a RUN-DOWN, GHOSTED, POORLY TUNED CRT emulator.

      A new, decent quality CRT is still better looking in a lot of ways than a LCD monitor.
      • Re:Overdid it. (Score:4, Insightful)

        by ElectricTurtle ( 1171201 ) on Thursday April 30, 2009 @09:30PM (#27782039)
        Wow, apparently people are missing the point. They obviously aren't trying to emulate 'new CRTs' what would be the point of that? Have you people forgotten what a 12" MCGA or EGA display from over two decades ago used to look like? I used to have one (MCGA) in working condition as recently as two years ago, and I can say the emulator is pretty close.

        Damn kids don't remember what shit used to look like before VGA, SVGA, XGA etc. came along and spoiled 'em. When I was growing up, I had one color! ONE! And it was the nastiest shade of amber ever conceived! At least I could play Airborne Ranger...
        • by mzs ( 595629 )

          I was lucky, my parents had a 19" Sony Trinitron in '82. The image quality was much much better than this. I had a friend at the time that had a Zenith and even that looked better than this. This project took the effect much to far.

        • Re: (Score:3, Insightful)

          by hairyfeet ( 841228 )

          Yes! preach brother! I grew up watching one of those big ass Magnavox TVs, and this is a pretty perfect representation of what we had in the 1970s. We had bleeding channels, and ghosting, oh and if you weren't careful you ended up with the pattern for something like Pacman "sticking" around for awhile.

          My mom of all people was addicted to Yar's Revenge and Donkey Kong JR (we had the ColecoVision [wikipedia.org] with the 2600 expansion module) and she would sit there playing Yars late at night and I would get up to watch car

      • I think it's specifically trying to reproduce the look of an old television CRT.
      • Re: (Score:2, Informative)

        by hattig ( 47930 )

        Yeah, because when I played computer games as a kid in the 80s, I played it on a brand new late-90s CRT display. Not an 8 year old hand-me-down 14" TV in the bedroom (albeit mine was a 14" Trinitron which was surprisingly competent and not as grainy as this emulator, and even good for the old Amiga). Then again they're emulating a late 70s CRT.

        If there is something this emulator doesn't do, it doesn't emulate what the poor signal quality on the cheap cable between the console and the TV that would create ar

    • I never did get why they put the fake-wear on those jeans in the one place that lasts longer than everywhere else and then leave the knees and ankle areas completely normal.

    • How old (young) are you? It looks quite accurate to me. Heck, I still remember playing 'TV games' on our old black and white TV.

    • I agree. I don't recall Atari games looking quite that bad on my TV screen. The effect here is more like looking at an old CRT from two inches apart, except you're really much further away.

    • by mzs ( 595629 )

      Also the images have no ringing. That is the effect when there was a high luminance area on the left with a sharp transition to a low luminance area to its right. There would a pattern of vertical lines at diminishing distances and with diminishing brightness from that edge to the right. That was the most annoying effect of systems that used RF modulators.

  • It reminds me of the audio effects that add pops and scratches to music to imitate (badly) the sound of old vinyl.

  • Why bother? (Score:3, Insightful)

    by Anonymous Coward on Thursday April 30, 2009 @09:14PM (#27781895)

    Honestly, craig's list is riddled with people throwing away CRT's. Why run a crappy emulation...if that is what you call it, when you can go next door and get CRT?

    • Re:Why bother? (Score:5, Insightful)

      by Bottlemaster ( 449635 ) on Thursday April 30, 2009 @09:38PM (#27782119)

      Why run a crappy emulation...if that is what you call it, when you can go next door and get CRT?

      Many of these artifacts are not just caused by the CRT, but result from other portions of the path from video RAM to the screen. The emulation creates an even more genuine experience than a computer CRT without compromising the convenience of an LCD.

    • I like my LCD. For any sort of productivity work or modern games, it looks way better than any CRT ever could. So I want to keep it. I don't want to haul out a CRT any time I want to emulate an older system. There's also the problem that computer CRTs won't do the trick. They are higher resolution, and have better signaling than NTSC sets. So they too will offer a different image than an old NTSC TV.

      There's no need to bother with all the physical hardware if it can just as easily be simulated by the compute

  • by CrazyJim1 ( 809850 ) on Thursday April 30, 2009 @09:19PM (#27781935) Journal
    bunk bunk bunk. Do do do weep.

    Isn't it sort of ironic that people want perfect emulation of Atari 2600 PacMan when Atari 2600's PacMan was notoriously not like the arcade version? Even NES didn't do emulation well. I think the first well emulated game I ever played was Street Fighter 2 on SNES.
    • The only place where i've heard about the atari 2600's pac man has been on like the top 10 lists of terrible games or worst games of all time or whatever because it so wasn't the arcade version.

      The only thing I was wondering was where could I play the emulated games?
    • by tepples ( 727027 )

      Isn't it sort of ironic that people want perfect emulation of Atari 2600 PacMan when Atari 2600's PacMan was notoriously not like the arcade version?

      Because for one thing, the port of Ms. Pac-Man to Atari 2600 [youtube.com] sucked far less. And I seem to remember a ROM hack of Ms. Pac-Man that restored the original Pac-Man boards

  • by Jah-Wren Ryel ( 80510 ) on Thursday April 30, 2009 @09:19PM (#27781951)

    So, can I get burn-in on my LCD monitor now?

    • The underlying mechanism is, obviously, different and they refer to it as "image persistence"; but LCD burn in is definitely available. This [hdguru.com] is a piece on it. Googling "LCD burn in" will pull up loads more. If you really want to see it for yourself, check out kiosks, library public computers, and other systems that spend most of their lives displaying the same image. It does happen.
      • by cskrat ( 921721 )

        Usually LCD burn in can be exorcised out with a simple rotating video of solid red, green, blue, black, magenta, yellow, cyan and white at a frame rate of about 10-20 fps. Run that overnight and it will often fix persistent images and occasionally stuck pixels.

  • Nice (Score:3, Insightful)

    by Trogre ( 513942 ) on Thursday April 30, 2009 @09:22PM (#27781965) Homepage

    Looks similar to the efforts the xscreensaver developers, with their m6502 and Apple2 hacks that simulate CRT artifacts such as static, colour separation, and shear.

  • by derGoldstein ( 1494129 ) on Thursday April 30, 2009 @09:40PM (#27782135) Homepage

    Here's a list of stuff I'd like to emulate, for the sake of nostalgia:

    286 without math co-processor
    trig function lookup tables
    horse dung smell in the streets
    Morse code
    the black plague

    Get on it!

    • by guruevi ( 827432 ) <evi&evcircuits,com> on Thursday April 30, 2009 @10:45PM (#27782599) Homepage

      Emulating old stuff:

      286 without math co-processor - Install Vista
      trig function lookup tables - You would be surprised that they are still being used (both in paper and in code)
      film - you mean like 35mm? There are filters in most semi-advanced photo programs that will emulate this.
      typewriters - http://www.instructables.com/id/Typewriter-Computer-Keyboard/ [instructables.com]
      horse dung smell in the streets - Go live in NYC, open the window and take a deep whif
      Morse code - Well, everything is still binary these days so technically it's similar to really fast morse code.
      the black plague - Swine flu?

      • trig function lookup tables - You would be surprised that they are still being used (both in paper and in code)

        Well in code, it's generally done in hardware to interpolate between two values. In software you can find lookup tables for programs meant for MCUs and really small architectures.
        But paper?... I'd need to see photographic evidence. I mean these days I really can't think of a situation where you'd find paper lookup tables for trig functions.

        film - you mean like 35mm? There are filters in most semi-advanced photo programs that will emulate this.

        I didn't consider that, though it's usually the emulation of what happens to the film under/in different environments. But technically it does emulate (simulate?) th

        • by guruevi ( 827432 )

          Try construction. I'm talking about old-school architectural engineers here. I recently saw somebody do it with a fairly simple formula to give an approximation on something. The younger engineer had to find and unwrap his scientific TI calculator and then was figuring out typing in the correct syntax of the formula when the old guy was already done doing it on paper. He kept a sheet (one can be found here: http://www.sosmath.com/tables/trigtable/trigtable.html [sosmath.com]) in the back of his notepad. The old guys on t

          • by cskrat ( 921721 )

            Pick up the "Pocket Ref" by Sequoia Publishing. [sequoiapublishing.com] It has everything from CPR instructions to structural material strengths. I picked mine up at a college book store but I'm sure I've seen them at Powell's Technical as well.

        • by cskrat ( 921721 )

          Sorry man. Paper tables [cskrattiger.com] do still exist.

          • Pocket Ref, third addition, by "Thomas J Glover", pages 460-473...

            I had it on my within-hand's-reach shelf. Includes squares, cubes, and roots. Unbelievable, I was just wondering how far back I'd have to search to find printed lookup tables within a published book.
            Apparently this one's still going strong [amazon.com].
      • > Don't support corporate radio any longer - listen to X1FM, raw and uncut internet radio. Go to x1fmradio.com for more in

        Don't know if you are being paid to spam for them or you are just an idiot. Hard to tell sometimes.

        1. It's as over compressed as the worst "Hundred Thousand Watt Blowtorch" FM station. Yuck!

        2. Don't support corporate radio... by going to a corporate radio site. Oh hell yea. Guess you never bothered to click on their about us link where they explain about their years of hard work

        • by tepples ( 727027 )

          Don't support corporate radio

          Then what radio should people listen to in a vehicle? Without 3G service, which costs $720 per year in the United States, one can't easily listen to Internet radio.

      • the black plague - Swine flu?

        The latest sources are calling H1N1 no worse than ordinary flu, which kills an average of 100 people a day in the United States. People are recovering from H1N1 on the same schedule that they recover from the more familiar flu. The only thing about H1N1 is that nobody has the immunity yet.

  • I don't get it... (Score:2, Insightful)

    by theNetImp ( 190602 )

    I don't remember my Atari looking like that on my TV. Sure it wasn't LCD perfect but it didn't suck that that does.

  • Now we need a Hercules video card [wikipedia.org] emulator for wordprocessing and CAD.
  • by phr1 ( 211689 ) on Thursday April 30, 2009 @10:20PM (#27782471)
    Modern web frameworks like Cobol on Cogs [coboloncogs.org] already do burned-in CRT emulation and various other effects too. ;-).
  • Vector? (Score:3, Insightful)

    by Tablizer ( 95088 ) on Thursday April 30, 2009 @10:52PM (#27782669) Journal

    Vector graphics may be the most difficult to emulate because of the potential brightness of specific spots. The brightest white on most LCD monitors cannot compare to such a spot. Asteroids is probably the most famous vector game. Basically, the electron beam could be controlled to "draw" the game via lines and dots instead of merely scanning back and forth at a fixed pace like traditional CRT's. The beam could "dwell" on a specific spot or line if needed, making it glow like nobody's mamma.

  • The highest res mode was black and white only, but due to limitations of the CRTs used in TVs at that time, if the pixels weren't a solid block, the color would shift to something not-white.

    Back then I wrote a drawing program that took advantage of the artificing to draw in color. I knew which pixels in a block could be turned on or off to generate one of up to about 16 colors. Obviously, the smallest blocks were only 5 colors. (Red, Green, Blue, Black, White) So the more detail you wanted your drawing,
  • We hated those miserable image anomalies back in the day, and it hasn't become more endearing to have it fuzzed up with modern technology just to look old again.

    Is this the new definition of progress? Use the best new technology we can find to generate the same old crap we already grew tired of?


  • Just like tube amplifiers for audio, the NTSC TV look is probably going to be sought after. We thought those artifacts were going to be around for all time & mastered how to choose colors that would always display. The new VGA monitors were too expensive & we weren't old enough to know any better.

  • was that they illustrated the performance using a jpeg file. Yes, the compression artifacts are different.

    It's rather ironic that there are more bits of data in the poorly rendered compressed version than there were pixels on the screen when you played a game on the real hardware.

  • UGH, I'm trying to forget those days. I used to play goddamn NES on a B&W portable-tv monitor, and of course Atari before that on even worse displays. Some games required you to see certain colors, notably Low-G Man. The red ones were a slightly darker shade of gray on a B&W tv /wrists

    The idea of being nostalgic for those days, or wanting to see things like that again, it's hard to believe. It's like people being nostalgic and going back to communism after the wall fell. IT'S SICK. It's like visual

    • Hmm yeah, Model T's are fun to ride in, but I wouldn't go so far as to call it comfortable. I think the same applies here, playing old games is fun, but they were ugly then and this filter makes them the same king of ugly. It really gives you the true experience I suppose. It is true that a lot of old games look arguably worse on a nice new LCD.


      I've played with the NTSC filter in an NES emulator before, and yes it really does look like the real deal, but its ugly to me so I have to turn it off :-)

  • NEStopia has a display filter they call 'NTSC' that can emulate television video of varying quality and standards. Complete with color bleed and a little bit of ghosting. This sounds like it's maybe a more sophisticated version of that idea. :D

  • Why is this news? There already is a module named "analogtv" in xscreensaver that does essentially the same thing. It might be moderately interesting when this actually gets released as part of Stella, but until then all we have are some screenshots that look very similar to existing TV simulators.

    By the way, the 80's TV sets I played Atari games on never showed afterimages, and flickering objects (like the ghosts in Pac-Man) flickered very clearly. I hope this effect will be optional.

    Personally I'd like to

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