Someone explain scan lines to me.......

[stargate]

Why are there scan lines on most or all full sized arcade games. Is it due to shitty quality monitors?

[stargate]

someone must know this.

[bargora]

what do u mean "scan lines"?

[sniperCCJVQ]

If you look very close to an arcade monitor, you can see that the display going like these:

game graphic line
black line
game graphic line
black line

I think this is scanline, but what it really does, i don't know.

[simonbelmont7]

i have no clue why they exsist, but personally, i think games look better with scanlines. Everything looks more crisp. Whenever you use an emulator to play stuff, i always have at least 50% scanlines enabled. :)

[digitalpress]

I don't know what technical innovation occurred to REMOVE scan lines from video games, but for example: your television set has scan lines, but modern PC monitors do not. As a result, you might set "scan lines=on" for a Genesis emulator (to simulate the TV experience).

We need a tech guy or gal for the real deal answer though.

[ManekiNeko]

I'm no expert on the subject, but this is what I remember from my computer repair classes. Monitors use dot triads (tiny red, green, and blue lights) which are shone through the holes in a shadow mask. This creates pixels, which in turn illustrate the screen.
The dot triads can't display the contents of the screen all at once, so horizontal sections of the picture- scanlines- are quickly drawn and refreshed. In some monitors, each consecutive scanline is drawn before the picture is refreshed, but in others, interlacing is used. That means that the monitor will draw the odd scanlines first, then return to the top of the screen and draw the even ones. It's my understanding that a monitor which uses interlacing is cheaper, but produces a less vibrant picture than a standard monitor.
I'm not sure why older monitors use blank scanlines to seperate the active ones. It's a possibility that the resolution on the monitor is very low, and this was an inexpensive way to increase the size of the picture.

JR

[stargate]

I'm no expert on the subject, but this is what I remember from my computer repair classes. Monitors use dot triads (tiny red, green, and blue lights) which are shone through the holes in a shadow mask. This creates pixels, which in turn illustrate the screen.
The dot triads can't display the contents of the screen all at once, so horizontal sections of the picture- scanlines- are quickly drawn and refreshed. In some monitors, each consecutive scanline is drawn before the picture is refreshed, but in others, interlacing is used. That means that the monitor will draw the odd scanlines first, then return to the top of the screen and draw the even ones. It's my understanding that a monitor which uses interlacing is cheaper, but produces a less vibrant picture than a standard monitor.
I'm not sure why older monitors use blank scanlines to seperate the active ones. It's a possibility that the resolution on the monitor is very low, and this was an inexpensive way to increase the size of the picture.

JR

I'm guessing you are right and in layman's terms scanlines result from low quality monitors. I mean, if you are an arcade game manufacturer, I'm sure it is not cost effective to use high end monitors when you have to produce thousands of machines.

Scan lines are interesting because I never really noticed them after years of playing arcade games until MAME came out and they had the option to use scan lines to make the game more realistic. Now, whenever I am at an arcade I notice them on every game I play. Sometimes, the scanlines are HUGE. There does not appear to be scanlines, however, when playing a home console, even early units such as Atari 2600, INTV, etc.

I think scanlines are cool looking for some reason, maybe because after playing games with scanlines in arcades for 20+ years, you kind of get used to them.

[davidbrit2]

Okay, here's the general explanation, straight from the physics geek. Have you ever played an old CGA or MCGA (320x240) game on a VGA monitor? You'll notice that each "pixel" is actually drawn by the video card as a 2x2 block of VGA pixels. This causes the large pixels to be extremely well defined. It does this because the electron gun illuminates a fairly narrow area as it scans the screen horizontally. If it were to scan just 240 lines down the screen, you would notice space between the lines, since the gun is designed to hit a very precise point. So on your monitor, when you're running lower resolution games, each scan line is actually made into two scan-lines by the modulator in your video card. This removes the appearance of gaps between the scan lines.

An arcade monitor experiences much the same phenomenon. Essentially, the size of the targeted area should be big enough to minimize the space between the gun scans, but not so large that the pixels within a scan line bleed together. Lower resolution RGB monitors found in arcade games are not precise enough that double scanning each line is necessary, since the space between scan lines is so small. Also, the low definition picture eliminates pixellation by giving roughly the same effect as applying a blur effect to the screen. So basically, all these special emulator video modes are trying to use a 21st century CRT to simulate the inadequacies of 1980s monitor technology. Heh.

And interlacing, by the way, is what's responsible for displays that appear to flicker and almost vibrate. Most arcade games that run at fairly high resolutions will do this in order to create a clear and viewable picture on the relatively low resolution RGB monitors.

[wberdan]

I don't know what technical innovation occurred to REMOVE scan lines from video games, but for example: your television set has scan lines, but modern PC monitors do not. As a result, you might set "scan lines=on" for a Genesis emulator (to simulate the TV experience).

We need a tech guy or gal for the real deal answer though.

i believe the answer to this goes something like this:

the computers we use run at a high resolution and use a progressive scan feature to reduce scan lines so they are almost undetectable to the eye. they do not remove scan lines. only CRT displays have scan lines because the tubes in the television have to scan the lines onto the display individually (i could be a little off on that- its been a while since i researched this). lcd or dlp displays do not use scan lines, and instead use pixels.
i cant pull out the reason exactly why they are so visable on old games, but i believe it has to do with using lower resolution sources (such as the actual game) on a monitor that is too large. our eye picks these lines out then. with progressive scan features on todays computers and all emulated technology, these scan lines essentially do not exist... which, in my opinion, makes the games look incorrect and some games actually have noticable flicker at parts because of the fast scanning of the computer monitors progressive scan.

im sure that some of what i said may border on false information, since i have not looked into this stuff in some time. i would ask that anyone with more interest look up how progressive scan works and that will help you better understand why this is so.

willie

[stargate]

so now I am wondering if the newest arcade games still have scan lines. I guess I will have to get down to an arcade and check it out.

I am guessing they will because low cost monitors will always be used, but that they will be less apparent on newer games.

[Tetsu]

Why are there scan lines on most or all full sized arcade games. Is it due to shitty quality monitors?

Here's the socio-economic explanation:

In the early days of TV, scan rates and resolution varied by maufacturer, as did the television signal broadcasted by early TV stations. After TV gained popularity, FCC regulations required TV stations to broadcast at the newly-developed NTSC 320x240 @ 60hz horizontal* standard. Scanlines are a product of TV's designed and built with these regulations in mind. Higher res were possible, but more expensive per set and counterproductive to having a standard. Arcade monitors are simple RGB computer monitors that don't need tuners or signal decoders like TV's do. Otherwise, they are quite similar to TVs. It makes sense that arcade monitors were designed with the same frequency and resolution standards as TV, so they could be maufactured and serviced just as easily. So no, the monitors aren't "shitty" in the sense that they are practical, cost effective, easy to maintain, and display a decent image. Are they "shitty" compared to modern monitors with much higher resolution? Depends. Arcade games designed for use on arcade monitors, modern computer games are designed for use on modern computer monitors. Expecting one kind of game to look just as good on a monitor it wasn't designed for will yield less than stellar results.

*50hz horizontal in Europe, aka the PAL standard, and SECAM in France, dunno the specs on it.


so now I am wondering if the newest arcade games still have scan lines. I guess I will have to get down to an arcade and check it out.

I'm sure they do, otherwise arcade operators would have to buy and install brand new monitors for new games in addition to swapping out game boards. I bet some high-end, newfangled, custom, oversized-cabinet racing/virtual reality might have hi res monitors, though.

[FABombjoy]

Here's the (sort of) quick and dirty explanation:

The circutry in a low-frequency monitor (like in most arcade games, and standard television sets) allows the electron beam to move only so fast. Typically, to get a high resolution display on these monitors, the picture is interlaced. Every other scan line is drawn, leaving black lines in between. Then, the beam draws in the missing lines. Each 'half-picture' is called a field. It is done this way because it is less expensive to produce a slower-scan monitor, and it is an effective form of 'compressing' and analog signal, so it uses less bandwidth. This is the mode used for standard broadcast television signals.

Low resolution/low framerate arcade games use monitors that share the same characteristics as consumer televisions, but the games would not benefit from drawing both fields. In fact, they may look flickery or the motion of the characters could look strange from having the scan lines 'doubled-up'. The hardware of an arcade game, which controls the monitor directly, simply says "draw so many scan lines over so much time", and it only uses a limited number of lines of resolution drawn over the entire height of the monitor. The monitor never receives anything about a second field. Hence why black lines appear inbetween the drawn lines. Fields do not have to exist in arcade hardware, since RGB is not a standard, like NTSC or PAL.

In-home console systems are bound to using broadcast signal standards to transmit the picture. In these cases, the system may or may not elect to send a 2nd field of information. Most older game systems do not. Right around the PSX/Saturn days, game systems that used both fields emerged. Without using both fields, the resolution of the game systems was severly limited to half of the effective resolution of the television set. You can see interlace flicker on a new system, but not on a Genesis.

Newer arcade games may use low, mid, or high-frequency monitors, and may use interlace or progressive scan. It's up to the manufacturer to balance picture requirements with hardware cost & determine the best monitor for a specific game.

Some of this was a bit of an oversimplification, but it works for the most part :)

[davidbrit2]

Okay, so the basic idea is that it's a single field display, meaning the scan lines are more obvious, much like in an old CGA, EGA, or other low res RGB computer monitor.


In-home console systems are bound to using broadcast signal standards to transmit the picture. In these cases, the system may or may not elect to send a 2nd field of information. Most older game systems do not. Right around the PSX/Saturn days, game systems that used both fields emerged. Without using both fields, the resolution of the game systems was severly limited to half of the effective resolution of the television set. You can see interlace flicker on a new system, but not on a Genesis.

Don't forget Battle mode on Sonic 2. ;-) That might be the only thing on Genesis that uses a two field display.

[FABombjoy]

Don't forget Battle mode on Sonic 2. ;-) That might be the only thing on Genesis that uses a two field display.

Oh yeah... I forgot about that. That thing rules... I wish they would have used to more often. I don't know what for... but I wish they did.