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Author Topic: Trick with using PC CRT  (Read 4893 times)

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Ummon

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Trick with using PC CRT
« on: July 08, 2008, 08:52:50 pm »
Well, this may not be a secret to many here, but for the newer folks it might be. If you're thinking of using a PC CRT in your cab, check out the following:

- set your desktop to 640x480

- if using Mame before the rewrite, set it to DDraw+hwstretch, no effects

- if using Mame since the re-write you can take your pick between DDraw+hwstretch or D3D (again, no effects). Set the prescale to 0; 1 sharpens it up slightly such that it makes it look a little weird.

What this does is by setting to 640x480 on this type of monitor, you get natural hardware scanlines, and since it's a system configuration, it displays everything this way. And since switchres into being used, all the games fill the screen properly.

Of course there's a slight bit of distortion, but this helps to just slightly blur the graphics such that it doesn't look as much like it's on a PC CRT; and you don't have the brightness issues that even the new effects produce; it's very brilliant and fresh. Additionally, if run in vertical orientation, vertical games actually look good with the naturally produced scanlines.

The only snag I can see is having the desktop stuck at 640x480....but perhaps some kind of batch file or something could be created so that only when Mame games are started is the desktop switched. And you'd have to be mindful of the switch back, because Windows like to change the refresh rate to 85 or higher. Food for thought, though.
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evilfuzzle

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Re: Trick with using PC CRT
« Reply #1 on: July 08, 2008, 09:13:45 pm »
interesting, i will have to give that a try :)

Minwah

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Re: Trick with using PC CRT
« Reply #2 on: July 09, 2008, 08:20:16 am »
Isn't 640x480 with no effects pretty much the most basic setup for Mame anyway? That is what I always use with a PC monitor.

No need to set your desktop to this tho (unless you want to)...just set mame's resolution to 640x480 and switchres 1.

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Re: Trick with using PC CRT
« Reply #3 on: July 09, 2008, 12:44:58 pm »
Also, IIRC, the pre-scale option pretty much does what it states.  It scales the graphics cleanly before applying the effects.  This prevents the effects from turning the pixels to fuzz when displayed on a high-res screen, and allows for a better representation of a low-res CRT pixel.  I'm not sure it provides much benefit when used in this manner, seeing as no effects are used?

RandyT

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Re: Trick with using PC CRT
« Reply #4 on: July 09, 2008, 12:54:59 pm »
Also, how does prescale of 0 differ from 1 (the default and minimum value)?  Seems as though either 0 or 1 would not scale the image.  From the MAME docs:

-prescale <amount>
  102 
  103      Controls the size of the screen images when they are passed off to the
  104      graphics system for scaling. At the minimum setting of 1, the screen
  105      is rendered at its original resolution before being scaled. At higher
  106      settings, the screen is expanded by a factor of <amount> before being
  107      scaled. With -video ddraw or -video d3d, this produces a less blurry
  108      image at the expense of some speed. In -video ddraw mode, this also
  109      increases the effective resolution of non-screen elements such as
  110      artwork and fonts. The default is 1.


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Re: Trick with using PC CRT
« Reply #5 on: July 09, 2008, 02:09:19 pm »
Something tells me this depends on the type of monitor.......
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Re: Trick with using PC CRT
« Reply #6 on: July 09, 2008, 03:05:56 pm »
Something tells me this depends on the type of monitor.......

Yeah, because I was using those exact settings on mine and didn't get scanlines. My 19" PC CRT monitor has a max res of 1600x1200, set to 640x480 32-bit@60hz and it looks too clean. Had to go turn on some effects to make it look right.

Ummon

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Re: Trick with using PC CRT
« Reply #7 on: July 10, 2008, 07:41:07 pm »
Something tells me this depends on the type of monitor.......

I wondered about this, but I don't think so. I have two different Dell monitors, one a 17" non-trinitron style that only goes up to 1280x1024, though native is 1024x768; the other is a 21" trinitron style and goes up to 2048x1600 or whatever. Both display as mentioned in my initial post. Oh, I also have another 21", some brand called Hyama, which has the same specs as the trinitron. Same result.

Ginsu: I'd have to see a close-up of your monitor to tell if you have it set up right. The scalines are very fine, but about the same fine-ness as using Aaron's 'real_scanline' effect.

Prescale: I forgot that the default is now '1', though originally it was '0', so leave it at '1' (which, like the doc ahofle posted says, is it's 'zero point').

Isn't 640x480 with no effects pretty much the most basic setup for Mame anyway? That is what I always use with a PC monitor.

No need to set your desktop to this tho (unless you want to)...just set mame's resolution to 640x480 and switchres 1.

Not on my computer - ie: setting DK to 640x480 within Mame makes it really small. Rotating it makes it bigger, but two issues: it still doesn't fill the screen; and though the hardware scanlines are very pronounced, the overall image is very pixelated. Windows at 640x480 isn't the same as a game run at 640x480.

However, I'd forgotten you can get the same effect as mentioned in my original post by setting it as you said but with the inclusion of hwstretch (ie: DD+switchres(@640x480)+hwstretch.) D3D after the re-write automatically scales it to full screen - hence set to D3D+switchres (@640x480). So that solves the desktop issue.

Of course, the geometry of 640x480 may not be set to the bounds of your monitor's display area, but Windows will be displaying full screen for the area covered. Set your geometry accordingly.
« Last Edit: July 10, 2008, 08:50:17 pm by Ummon »
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Re: Trick with using PC CRT
« Reply #8 on: July 11, 2008, 11:28:42 am »
Yeah, because I was using those exact settings on mine and didn't get scanlines. My 19" PC CRT monitor has a max res of 1600x1200, set to 640x480 32-bit@60hz and it looks too clean. Had to go turn on some effects to make it look right.

As a side note, if your system can handle the additional processing requirements without slowing down, your image will look much better if you use a higher resolution, set the prescale value appropriately (varies based on the resolution) and then apply the effects.

RandyT

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Re: Trick with using PC CRT
« Reply #9 on: July 11, 2008, 12:21:26 pm »
Yeah, because I was using those exact settings on mine and didn't get scanlines. My 19" PC CRT monitor has a max res of 1600x1200, set to 640x480 32-bit@60hz and it looks too clean. Had to go turn on some effects to make it look right.

As a side note, if your system can handle the additional processing requirements without slowing down, your image will look much better if you use a higher resolution, set the prescale value appropriately (varies based on the resolution) and then apply the effects.

RandyT

Thanks for the tip, but I've only got a 733mhz in my cab.

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Re: Trick with using PC CRT
« Reply #10 on: July 11, 2008, 12:55:28 pm »
One cool thing you can try with a pc crt is 31.5 khz modes.  Several old CRT monitors can handle this. 

I have two Sony Trinitrons that support this mode.  In advancemame I have set this mode and applied scan lines and the difference between this mode and 15.75 khz modes on my other monitor are minimal.  The only difference I can tell is that the that the 31.5 khz mode is a little darker and duller with the fake scanlines than the real 15.75 khz resolution.  But it still looks very good.  I think it actually looks better to just leave them off and live with the slightly pixelated looking 31.5 khz mode, as the brightness is very good. 



« Last Edit: July 11, 2008, 01:02:49 pm by megaultrasuper »

ahofle

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Re: Trick with using PC CRT
« Reply #11 on: July 11, 2008, 03:30:26 pm »
One cool thing you can try with a pc crt is 31.5 khz modes.  Several old CRT monitors can handle this. 

Isn't that what the OP is suggesting?  (640x480 = 31khz)

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Re: Trick with using PC CRT
« Reply #12 on: July 11, 2008, 06:09:37 pm »
One cool thing you can try with a pc crt is 31.5 khz modes.  Several old CRT monitors can handle this. 

Isn't that what the OP is suggesting?  (640x480 = 31khz)

I didn't even realize there are CRT PC monitors that don't support 31.5Khz. I feel like Rip Van Winkle half the time. :dizzy:

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Re: Trick with using PC CRT
« Reply #13 on: July 12, 2008, 01:02:20 pm »
One cool thing you can try with a pc crt is 31.5 khz modes.  Several old CRT monitors can handle this. 

Isn't that what the OP is suggesting?  (640x480 = 31khz)


I don't know the specific's, but I can get a much better picture in advance mame setting the resolution to 31.5 khz than I do in mameui or mame by setting the resolutio to 640x480 with no scaling.  Perhaps if I did some of thing discussed in this thread I would get the same results.  I think maybe advancemame is doubling the resolution to exactly 672x480 instead of 640x480.   

Xiaou2

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Re: Trick with using PC CRT
« Reply #14 on: July 12, 2008, 01:17:51 pm »
 The biggest issue with making a PC/Lcd monitor look like an arcade monitor is not the
lines.  Its the color bleed and mixing and slight blur & glow.

 What really needs to be done... is to use software to simulate the pixel color mixing/bleeding
on the fly.  Now that we have dual (and quad..) core pcs... it would be great to use that
extra processor to do the image output.

 OR Maybe

 Randy could whip up a hardware version... which then would take a vga input.. tweak it,
then output it to the monitor.

 
 
« Last Edit: July 12, 2008, 01:19:53 pm by Xiaou2 »

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Re: Trick with using PC CRT
« Reply #15 on: July 14, 2008, 11:32:02 am »
The biggest issue with making a PC/Lcd monitor look like an arcade monitor is not the lines.  Its the color bleed and mixing and slight blur & glow.

 What really needs to be done... is to use software to simulate the pixel color mixing/bleeding on the fly.  Now that we have dual (and quad..) core pcs... it would be great to use that extra processor to do the image output.

There's no need to do this in hardware.  The MAME team is already doing some pretty cool things with the manipulation of the image.  Once we see affordable, super-high-resolution video display devices and hardware powerful enough to drive them, I have no doubt that the folks working on MAME at that time will have the algorithms available to truly simulate the old screens.  But there's not an awful lot more that can be done at this stage of the game.

Oh, and the lines are still a necessary element.  They don't have to be super pronounced, but they do need to be there.

RandyT

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Re: Trick with using PC CRT
« Reply #16 on: July 14, 2008, 05:42:29 pm »

 The Mame team is not really all that interested in such endeavors.    In
fact, at one point in time, they were about ready to remove the
current 'Effects' that are in there.

 I have doubts that anyone is ever going to release a 19" monitor that can
do resolution at the needed level of being able to duplicate the actual
shadow masks.    There is really no need for it.   Instead, they will simply phase
out smaller screens,  and produce all larger screens at Adequate resolutions.

 We all know that LCDs do not look well at non native resolutions.  And
most people dont want to use magnification glasses to view their windows
text.

 We also know there is a good market for authentic looking arcade monitors
on the cheap.    You can grab a 17" svga monitor at the thrift shop for
$10. (if you dont already have 2 or 3 lying around already)

 As for the lines...  well, Imop,  the lines just do not make the picture look
anywhere near authentic at all compared to color bleed and mixing.

 Also...  theres no reason to have to rely on resolution levels for effects.  One
can scale effects to fit the desired output resolution. (within reason)

 And finally... There are many other Emus such as console systems which
would also benefit from such a solution.   I think it would be a great seller -
If someone had the know-how to pull it off well...


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Re: Trick with using PC CRT
« Reply #17 on: July 14, 2008, 06:11:00 pm »
Well, without the extra resolution, there is not much else that can be done. It's not technically possible with a fixed resolution screen.  And if you believe it is, I'd like to hear the approach you think can be taken.

And if the MAME team were "all about scrapping the current effects", they probably wouldn't have put all that effort into the current crop.  So it appears that they have changed their minds, if that was indeed the case.

RandyT


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Re: Trick with using PC CRT
« Reply #18 on: July 14, 2008, 06:22:36 pm »
re: scanlines not being enough and the need for more color bleed options/filters in MAME.

ZSNES and some other console emulators have a new-ish software filter (aptly titled NTSC) that adds lines and has adjustable effects for color bleed, etc.  I see no reason they can't be ported or coded from the ground up for MAME.

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Re: Trick with using PC CRT
« Reply #19 on: July 15, 2008, 02:08:14 am »
re: scanlines not being enough and the need for more color bleed options/filters in MAME.

ZSNES and some other console emulators have a new-ish software filter (aptly titled NTSC) that adds lines and has adjustable effects for color bleed, etc.  I see no reason they can't be ported or coded from the ground up for MAME.

Holy crap man, you weren't kidding. I just hit up the zsnes site (first time since 1.41) and checked out NTSC... That filter is absolutely AMAZING. It does composite, S-Vid, and RGB (with a ton of variable filters) to a T. It was like being taken back through time... except on my 61" samsung LED DLP. It's a million times better than playing in HQ4x or any of the SAI filters.

Thanks a million for the heads up on that. I'll donate generously to any kind soul willing to port this filter to Mame  :applaud:

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Re: Trick with using PC CRT
« Reply #20 on: July 15, 2008, 01:09:18 pm »
I just checked out the video options in ZNES.  For what it is doing (variably crapping up the image to make it look like an RF, composite or even S-video screen) it does a fantastic job.  Unfortunately, it doesn't cross over quite as well for RGB arcade games.  It's also a little broken, as moving the sliders at all in RGB preset, causes the image to go bad, with only another click on RGB as a means to recover. :)  But for the most part, these type of effects, sans the active "jitter" effects, can already be applied in MAME. 

To my eyes, ZNES "NTSC" is using an alpha mask to create the scan line / pixel softening effects.  The mask is either generated on the fly, or is a bitmap that can go evenly  into an optimal vertical resolution.  The negative effect of low resolution can be seen quite clearly by noting the difference in quality between a 640x480 screen res and one that is 1280x960.  The extra resolution allows for things like bleed and scan line simulation, as well as non-sharp-cornered pixel representation.  At 640x480, these effects fall apart as they have inadequate space in which to perform.

As a console emulator, ZNES has a very important advantage; it's native resolution remains constant.  Such is not the case in MAME.  This means that one cannot do this as effectively without having a fixed resolution that is several times the native resolution of the title, and a separate, well planned alpha mask created specifically for those resolutions.  AFAIK,the current issue with the way MAME handles alpha masks is that there is no easy way to make sure that the mask aligns properly with the pixel data using anything other than DirectDraw to fix the output resolution, if it's even possible then.  And nothing screws up a good alpha mask worse than having the part that is supposed to be simulating a darker scan line overlaying what should be the clear pixel data.

But if one were to take the time to create proper masks for each resolution, and used DirectDraw on a high-res display, one could probably get similar results.

As a final note, just want to make the comment that the images of the arcade Turbo monitor shown above are not a good example of properly functioning RGB monitor.  The monitor shown is quite obviously very old and in poor shape.  While one may wish to additionally simulate that appearance, it probably is not the type of image produced by a shiny, new "low res" RGB monitor that most would be hoping for.

RandyT

« Last Edit: July 15, 2008, 01:18:25 pm by RandyT »

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Re: Trick with using PC CRT
« Reply #21 on: July 15, 2008, 01:40:13 pm »
I just thought I'd add (since most of you probably don't visit the monitor/video forum very often) a link to a great comparison of arcade monitor vs MAME scaling.

http://forum.arcadecontrols.com/index.php?topic=66402.msg858277#msg858277

Ummon

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Re: Trick with using PC CRT
« Reply #22 on: July 15, 2008, 07:12:53 pm »
One cool thing you can try with a pc crt is 31.5 khz modes.  Several old CRT monitors can handle this. 

Isn't that what the OP is suggesting?  (640x480 = 31khz)


Yes, 640x480 is 31khz. Even at 800x600, these monitors will produce hardware scanlines. It's at 1024x768 and above that they don't. In any case, it literally takes seconds to try this out if you have a PC CRT hooked up to a computer with Mame32/UI: start it, select the appropriate properties in DK, and start the game. Exit, switch to vertical orientation, and start the game.

I don't know what resolution mega's running at. I'd like to see his rc file. Of course, these monitors will also go past 120hz, so there's that option, too. I don't prefer it because the blank lines are almost as thick as those drawn. It's a matter of dot pitch. The dot pitch on my 27" presentation monitor, of course, is round the same as any 27" monitor, hence 120hz produces the same type of display as 15khz@60hz does on 27" arcade monitors.
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Re: Trick with using PC CRT
« Reply #23 on: July 15, 2008, 08:59:27 pm »
Kagaden: Yeah man, that filter was added in the latest release (1.51) I believe and it is a blast!  I too would bank roll something like this for MAME.

Randy: I don't get that bug in the NTSC filter on ZSNES.  However, ZSNES and its filters are horridly picky with nVidia drivers.  Perhaps it is driver related for you.  In fact, I can't even enable it (or the HQx) filters in the menu.  I have to turn those filters on in the config file manually.  Once NTSC is set to "on" in the file I can adjust properties in the emulator. 

I just run a custom setting on that filter that doesn't degrade the image too much, has a little bit of bleed and I eliminate any of the simulated "static" and "anomalies" from the filter.  It basically looks like you are playing SNES on one of the best SD CRT TVs one could buy in those days and properly calibrated.  Perhaps I'm not a purist, but I'd love to be able to get the results I do with ZSNES in MAME.  This is so much better than just running scanlines filters ebcause I can push the whites and color saturation as well.  This gives me the lines and mild bleeding, but doesn't make white look like gray nor does it dull the vibrance of the original colors like most scanline options I've seen.

I realize the issues with the doing a mask like this in MAME, but just because it would be difficult doesn't mean it can't happen.  Here's to hoping!

I will say that I do use advanceMAME and I am able to get a similar result, but it isn't nearly as tweakable as ZSNES for this purpose.

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Re: Trick with using PC CRT
« Reply #24 on: July 16, 2008, 10:45:03 am »
Xiau2, I'll agree there's more to it than the lines, but lines are pretty visible as one effect of RGB monitors, followed by the "blobby" pixel shapes, etc. A lot depends also on the focus setting of the monitor.

(Click image to see animation):
NO MORE!!

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Re: Trick with using PC CRT
« Reply #25 on: July 16, 2008, 11:13:05 am »
One cool thing you can try with a pc crt is 31.5 khz modes.  Several old CRT monitors can handle this. 

Isn't that what the OP is suggesting?  (640x480 = 31khz)


Yes, 640x480 is 31khz. Even at 800x600, these monitors will produce hardware scanlines. It's at 1024x768 and above that they don't. In any case, it literally takes seconds to try this out if you have a PC CRT hooked up to a computer with Mame32/UI: start it, select the appropriate properties in DK, and start the game. Exit, switch to vertical orientation, and start the game.

I don't know what resolution mega's running at. I'd like to see his rc file. Of course, these monitors will also go past 120hz, so there's that option, too. I don't prefer it because the blank lines are almost as thick as those drawn. It's a matter of dot pitch. The dot pitch on my 27" presentation monitor, of course, is round the same as any 27" monitor, hence 120hz produces the same type of display as 15khz@60hz does on 27" arcade monitors.

Not getting scanlines. Exactly what should be on and off? I tried what you said in the first post and it didn't work for me. Could you post copy and paste what's in the INI?

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Re: Trick with using PC CRT
« Reply #26 on: July 16, 2008, 12:11:47 pm »
Xiau2, I'll agree there's more to it than the lines, but lines are pretty visible as one effect of RGB monitors, followed by the "blobby" pixel shapes, etc. A lot depends also on the focus setting of the monitor.

(Click image to see animation):


One problem with your demonstration:  The scan lines on Turbo are vertical. :)  The horizontal lines you see are from the shadow mask, and the fact that they aren't very straight points to an issue there as well.

You just can't see the scan lines in the example due to some pretty significant focus and convergence issues with the monitor.

RandyT
« Last Edit: July 16, 2008, 01:07:30 pm by RandyT »

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Re: Trick with using PC CRT
« Reply #27 on: July 16, 2008, 12:51:47 pm »
oh, I see what you mean. The red green and blue are not aligned.
NO MORE!!

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Re: Trick with using PC CRT
« Reply #28 on: July 16, 2008, 06:24:47 pm »
Scan lines are more of an illusion.   You usually see a monitor drawing when its
captured by a tv camera.   The drawing is so fast, that you wont easily capture it on
camera.

 What you see close up, (and even partially at a distance)
 is the Shadow mask.  Its a mesh screen that seperates the
 red, green and blue dots.   The lines look wavy... and it took me a while to realize
 why.   Turns out its an illusion as well.   The bright colors bleeding and expanding
past the mask's borders, creates the illusion that there is no line segment in
certain spots.   There is also the traditional illusion with bright colors and lines
which fool the brain as well.

 What is also interesting... is that each  R,g and B  pixel area... can be lit up fully,
or in part.   Thus,  you see examples where 1/4 th the red pixel dot is lit - while the
rest of it is dark.

 Interestingly,  you would think that the colors should be  Red, Yellow, Blue.   
But the TV uses green instead!   Why?   When the green is lit to insane levels...
it changes appearance to yellow.    Red can change to bright orange.  Deep
dark blue can be very bright light blue.  All this without the need for use of
2 colors,  as would be needed for painting.

 Another thing to consider is how different Dot pitch will make a display look
completely different.   I believe dot pitch is the size of the r,g,b  sections.
(or all 3 combined into one)     Its very clear when you look at your pc monitor
how a small dot pitch changes the look of the output compared to your tube
TV.   You can not even grasp a hint of a shadowmask... yet it is there,  its just
amazingly small. 

 Similarly,  there is more than likely a big difference in the low res monitors
made at the time of Turbo,  than the ones made today.    I believe the dot pitch
is smaller now.. and they use a form of scaling to make up the difference.   Thus,
todays new low-res monitors would actually show very visible dark lines where
the extra unused pixels were.

 The guns themselves may be more accurate..  as well as refined materials and
other technology to reduce bleeding and mixing.

 (did you know that to make a menu look transparent on an arcade monitor -
they simply spaced the pixels out in a staggered pattern,  like a diagonal mesh.   
The mesh was thin and without a nearby pixel to boost its brightness power.. it becomes very dim, and appears to be translucent.   )


 As for my old monitor not being 100% accurate... thats only part true.   Its also
a reality of the way most of us saw them in operation back in the day.   Unlike
digital lcds... where when crisp detail is lost its very noticeable...  these games were
drawn with the bleeding and mixing in mind.    That the best display would
mix things... and even the dusty old display may even improve look.

  Notice the pinkish color on the turbo car  (pc monitor).   Its clearly Not supposed to
look anything like that.  However, when its outputted to the arcade monitor...
there is a big blending effect that simply causes a slightly lighter red highlight.

 No  Simulated lines are going to reproduce that!

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Re: Trick with using PC CRT
« Reply #29 on: July 16, 2008, 06:48:27 pm »
more pics

 1)  Shadowcar = Better pic of car
 
 2) Scanline = Shows with long exposure you can capture the drawing line.
However - at speed,  your eyes simply can not detect this to any good degree..
else games would have been murder on the eyes.

 3) Perfect shadowmask = These shots are VERY hard to accomplish,  esp
without a top of the line camera.   Another great shot showing the details of the
mask.  Probably took 30 bad photos before I got that good one.

 4) Magnify = Fooling around with a magnify glass,  I held it up to the monitor.
If you look in the background,  you can see the differences in looks that the
SHADOWMASK makes as its viewed from a distance.  NOT A SCANLINE.
« Last Edit: July 16, 2008, 06:54:08 pm by Xiaou2 »

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Re: Trick with using PC CRT
« Reply #30 on: July 17, 2008, 12:06:17 am »
Scan lines are more of an illusion.   

This is a really bad way to think about this....

Ignoring the fact that if you subscribe to this conclusion, you must also subscribe to the idea that the entire image is an illusion because it is simply 3 converged beams forming a dot at any one given place on the screen, there is this stuff called phosphor on the inside of the tube that continues to emit light even after the beams have moved away from it.  How long it continues to do this is based on the type of phosphor used, which is why the phosphor type is called out as part of the specification for any given tube.

But regardless of that, you have what is called "persistence of vision".  Your brain can only process visual imagery so quickly, which is why you can watch a movie with 24 frames per second separated by blackness and see moving imagery without obvious flicker.  We can argue all day long about whether something is real because we can only perceive it as such, but the plain fact is that lines are created, and we can see them.

As the beams move horizontally across the screen, and have physical space separating them, there are indeed lines formed by the scanning.  Scan lines is a real term and it refers to exactly the thing that you would expect it to refer to; lines created by the scanning method.  Even very high frequency displays have them, but they are far less apparent because they are spaced much tighter together. 

Quote
What is also interesting... is that each  R,g and B  pixel area... can be lit up fully, or in part.   Thus,  you see examples where 1/4 th the red pixel dot is lit - while the rest of it is dark.

Again, this is absolutely minimized on a properly adjusted display.  If another color is being consistently illuminated when it should not, even partially, you have "color purity" issues.

Quote
Interestingly,  you would think that the colors should be  Red, Yellow, Blue.   But the TV uses green instead!   Why?   When the green is lit to insane levels...it changes appearance to yellow.    Red can change to bright orange.  Deep dark blue can be very bright light blue.  All this without the need for use of 2 colors,  as would be needed for painting.

Steve, please stop.  You are doing the readers of this board a grave disservice.  It's so far off of the mark, I hesitate even to quote it.  Mixing light is very different from mixing pigments.  With light, the primary colors are red, green and blue.  Primary colors from a standard color chart, i.e. reflected colors (frequencies of light neither transmitted nor absorbed) are red, yellow and blue.

With light sources, CRT's, LED's, etc.. you get yellow by mixing red and green.  You get orange by mixing less green with the red.  Bright blue is achieved by mixing equal parts of red and green with high intensity blue, thereby adding a higher "white" or intensity component. 

If you are getting orange from your red gun, it is simply because the gun is no longer properly aligned with the shadow mask, or the gun is so severely out of focus it is creating muddy color by bleeding into the surrounding colors.  You are describing the characteristics of a "broken, or maladjusted monitor", not a properly functioning one where these things are much, much more well controlled.

Quote
Another thing to consider is how different Dot pitch will make a display look completely different.   I believe dot pitch is the size of the r,g,b  sections. (or all 3 combined into one)     Its very clear when you look at your pc monitor how a small dot pitch changes the look of the output compared to your tube TV.   You can not even grasp a hint of a shadowmask... yet it is there,  its just amazingly small. 

Usually, the dot pitch of a monitor is pretty closely matched to the scanning capabilities of the tube.  It would make no sense at all to have a very fine dot pitch on a display that was capable of scanning at only 15.75khz (CGA) as it would be a more expensive component that is never taken advantage of.  This is why you see large dot pitches on TV's and Arcade monitors and small dot pitches on PC monitors.  As a side note, the dot pitch of a shadow mask is why there is a real raster resolution equivalent to a color vector monitor.   As color vector monitors have shadow masks (unlike mono ones, which do not) the vector imagery can be no higher in resolution than the shadow mask allows.

Quote
Similarly,  there is more than likely a big difference in the low res monitors made at the time of Turbo,  than the ones made today.    I believe the dot pitch is smaller now.. and they use a form of scaling to make up the difference.   Thus, todays new low-res monitors would actually show very visible dark lines where the extra unused pixels were.

The guns themselves may be more accurate..  as well as refined materials and other technology to reduce bleeding and mixing.

Where's the head shaking smiley when you need one :).  As a tube and the circuitry ages, all of  those important controls become less able to perform their jobs.  The phosphor can burn away (screen burn), the filaments in the color guns will corrode and/or use up the coating from which the electrons are created, making for weak output.  The capacitors and other components which control timing and geometry start going out of tolerance.  The shadow masks can move from being shaken or bumped a little too hard in transportation from one place to another, or warp/move from years and years of being heated and cooled.  These are just some of the things a CRT can experience over time.

If you are trying to compare a monitor with 20 years of use with a new one, regardless of the date of manufacture....well, let's just say that whatever conclusions you draw will not have much validity.  The dot pitches are not especially smaller today for the same frequency of display, but you will probably be less likely to find the traditional dot triad type of mask. 

Quote
these games were drawn with the bleeding and mixing in mind.

While this is true, they were not drawn with a malfunctioning display in mind.  In fact, some graphics were so meticulously planned to take advantage of the way CRTs work that anything but a properly functioning display would cause the graphic to turn to "mud", not terribly unlike that representation of the Turbo car you are showing.

RandyT
« Last Edit: July 17, 2008, 02:55:09 am by RandyT »

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Re: Trick with using PC CRT
« Reply #31 on: July 17, 2008, 12:14:15 am »
2) Scanline = Shows with long exposure you can capture the drawing line.  However - at speed,  your eyes simply can not detect this to any good degree..else games would have been murder on the eyes.

This is not a scan line.  You are showing the image in mid refresh.  They are not the same things.

RandyT

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Re: Trick with using PC CRT
« Reply #32 on: July 17, 2008, 01:18:53 am »
Interestingly,  you would think that the colors should be  Red, Yellow, Blue.   
But the TV uses green instead!   Why?   When the green is lit to insane levels...
it changes appearance to yellow.    Red can change to bright orange.  Deep
dark blue can be very bright light blue.  All this without the need for use of
2 colors,  as would be needed for painting.

No, no, no. You are spouting the same kind of nonsense that only encourages more FUD. When it comes to mixing colors in video, throw out your subtractive color tables and go find additive color tables instead....

Thanks for nothing Randy. Stop quoting him so I don't get my curiosity going.  :angry:

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Re: Trick with using PC CRT
« Reply #33 on: July 17, 2008, 01:32:21 am »
Where's the head shaking smiley when you need one :).

I think it would be justified to borrow one from elsewhere.






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Re: Trick with using PC CRT
« Reply #34 on: July 17, 2008, 03:06:08 am »
I just checked out the video options in ZNES.  <snip>
RandyT

Makes a lot of sense. Thanks for the insight Randy! A guy can dream but I won't hold my breath now  :laugh:

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Re: Trick with using PC CRT
« Reply #35 on: July 17, 2008, 06:21:43 pm »
Randy, thank you so very much for the insightful posts.  I've learned something here and that is awesome!   :cheers: to you!

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Re: Trick with using PC CRT
« Reply #36 on: July 17, 2008, 09:09:48 pm »
Um, Xiaou2, while the exchange between you and Randy is illuminating in ways, I ask you don't get too involved in it here.


I just checked out the video options in ZNES...But for the most part, these type of effects, sans the active "jitter" effects, can already be applied in MAME.

Really? I don't like it anyway, but I didn't know Mame could do that.


@Room: running my integrated Intel video, I didn't have any trouble with the NTSC effect or any other filters on ZSNES. Although I did have trouble with running the particular rom I found. Not that it matters, as I just wanted to see the effect, which you can demo from the fe main screen. The NTSC effect is pretty decent.


Quote
The negative effect of low resolution can be seen quite clearly by noting the difference in quality between a 640x480 screen res and one that is 1280x960.  The extra resolution allows for things like bleed and scan line simulation, as well as non-sharp-cornered pixel representation.  At 640x480, these effects fall apart as they have inadequate space in which to perform.

And at 640x480 on a PC CRT, there's already hardware scanlines. Ginsu, get that ZSNES emulator and start it. By default, it should display at 640x480. If it isn't, set it there. When it is, there should be very noticable hardware scanlines due to the resolution. Just like if I set the desktop to VGA, or run a Mame game with at VGA+hwstretch. If not, then I have no idea. Below are some camera pictures of what it looks like. For the 640x480 pics, you may need to save and view at high resolution as the lines are fairly fine. Actually, I just viewed them, and it's hard to see - but the ZSNES 640x480 pic I think it is visible.



-- using the original posts settings:

- bubbles

- DK horizontal orientation

- DK vertical orientation



--using ZSNES

- 25% scanlines

- NTSC composite

- NTSC s-video

- NTSC rgb

- no effects, resolution configuration = 640x480 SF (stretched, full screen)
« Last Edit: July 17, 2008, 09:12:06 pm by Ummon »
Yo. Chocolate.


"Theoretical physics has been the most successful and cost-effective in all of science."

Stephen Hawking


People often confuse expressed observations with complaint, ridicule, or - even worse - self-pity.

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Re: Trick with using PC CRT
« Reply #37 on: July 17, 2008, 09:27:08 pm »
By the way, Ginsu, here are my ini files.


Also, remember that one can create high refresh modes (31khz, 120hz) and get hardware scanlines, as seen below. (Afte clicking the thumb, click on the picture to magnify.)
« Last Edit: July 17, 2008, 09:28:48 pm by Ummon »
Yo. Chocolate.


"Theoretical physics has been the most successful and cost-effective in all of science."

Stephen Hawking


People often confuse expressed observations with complaint, ridicule, or - even worse - self-pity.

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Re: Trick with using PC CRT
« Reply #38 on: July 17, 2008, 09:56:21 pm »
I just checked out the video options in ZNES...But for the most part, these type of effects, sans the active "jitter" effects, can already be applied in MAME.

Really? I don't like it anyway, but I didn't know Mame could do that.

I don't like any of the presets for it, but I've achieved something very close to what I personally want out of such filters.  That being an image that has scanlines that looks like it is from a properly calibrated high quality SD 4:3 TV circa the mid 90's.  That is the type of TV I played all my consoles on and that is waht I'd like to emulate.  I've done so successfully with the NTSC filter and custom settings.

Although I get similar results in advanceMAME, it isn't the same there is a big lack of control/tweaking options compared to ZSNES...unless I'm missing something.  Perhaps Randy could explain further on how to achieve this???  Pretty please?

Quote
@Room: running my integrated Intel video, I didn't have any trouble with the NTSC effect or any other filters on ZSNES. Although I did have trouble with running the particular rom I found. Not that it matters, as I just wanted to see the effect, which you can demo from the fe main screen. The NTSC effect is pretty decent.

You shouldn't have issues.  All the issues I've ever had with it were due to nVidia drivers.  It still works 100% the GUI just crashes when you enable it (or HQx).  I jsut have to turn it on using the config file, then all is good in the video menu.

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Re: Trick with using PC CRT
« Reply #39 on: July 18, 2008, 01:54:20 am »
This is a really bad way to think about this....

Ignoring the fact that if you subscribe to this conclusion, you must also subscribe to the idea that the entire image is an illusion


 That is exactly what I was getting at.   Most of what is seen is an illusion. 
The difference is that I am saying is that what a person is seeing is not an
actual line from the drawing - but instead,  the lines are simply from the
shadowmask instead.   


  Your brain can only process visual imagery so quickly, which is why you can watch a movie with 24 frames per second separated by blackness and see moving imagery without obvious flicker.  We can argue all day long about whether something is real because we can only perceive it as such, but the plain fact is that lines are created, and we can see them.


  If they are going so fast you cant see them...  are you really sure you are
seeing them?    Or is it really just mostly the shadowmask + the illusion
of the darks and lights throwing off your perception?


As the beams move horizontally across the screen, and have physical space separating them, there are indeed lines formed by the scanning.  Scan lines is a real term and it refers to exactly the thing that you would expect it to refer to; lines created by the scanning method.  Even very high frequency displays have them, but they are far less apparent because they are spaced much tighter together.



 As far as I understand it...  As the electron beams pass,  they Re-Illuminate the phosphors.  Each lit phospher will darken at a set rate.  The beams do not create
the darkness...  instead,   that darkness is the phosphors darkening on their own.

 

Quote
What is also interesting... is that each  R,g and B  pixel area... can be lit up fully, or in part.   Thus,  you see examples where 1/4 th the red pixel dot is lit - while the rest of it is dark.

Again, this is absolutely minimized on a properly adjusted display.  If another color is being consistently illuminated when it should not, even partially, you have "color purity" issues.


 
 Strange, because my 27" CRT TV, capable of 480I, which really doesnt get too
much use and is in near perfect condition shows the same traits under my 5x
magnification loop.    The individual RGB phosphors can be partially illuminated. 
Look at moving images yourself under magnification.  Anyone can see it...even on
brand new lower-res CRTs.



 You get orange by mixing less green with the red.


 Yet, in the pics I see that Red alone is let up to be orange.  Green is not
needed.


Bright blue is achieved by mixing equal parts of red and green with high intensity blue, thereby adding a higher "white" or intensity component.

 
 My mistake.  I see in the pic that they used green and blue to create the
light blue / canyon  color in turbos tires.   There was a hair bit of red too, but
mostly dominant green and blue.


If you are getting orange from your red gun, it is simply because the gun is no longer properly aligned with the shadow mask, or the gun is so severely out of focus it is creating muddy color by bleeding into the surrounding colors.  You are describing the characteristics of a "broken, or maladjusted monitor", not a properly functioning one where these things are much, much more well controlled.

 Not so sure about this.  I think the effect is simply the red being brightened to the
point of appearing orange.   I will confirm it against my good new tv when I
get the chance however.


Usually, the dot pitch of a monitor is pretty closely matched to the scanning capabilities of the tube.  It would make no sense at all to have a very fine dot pitch on a display that was capable of scanning at only 15.75khz (CGA) as it would be a more expensive component that is never taken advantage of.  This is why you see large dot pitches on TV's and Arcade monitors and small dot pitches on PC monitors. 



 How would you know about what these costs factors are?   Hes a hypothetical
reasoning:

   THey make a lowres monitor that have a large dot pitch..  however,  in a year
or so,  they improve the ability to make more precise masks.  This may help cut
down on possible degradation effect over the lifetime of the unit.. and may
reduce bluring and bleeding. 

  Games made before that change were designed to utilize the certain qualities
of the larger dot pitch.   However,  newer games could be designed to use
the slightly crisper qualities of the newer monitors.

 It may be possible that the extra resolution was cheaper to make,  as they
may have been using that same mask on other non arcade Tvs.
  They could have simply just altered the arcade guns positions to skip over the
extra lines that were no to be used.   OR,  it simply scaled the picture, using 2 or
more rgb groups for what was one group before.

 All I know is that last time I looked at the new low res monitors... their dot
pitch was higher than those of the past.   One has to conclude that the
display output must have looked different because of it.



The dot pitches are not especially smaller today for the same frequency of display, but you will probably be less likely to find the traditional dot triad type of mask.

 - Well, if you are trying to say that the frequency controls where the
lines are drawn... then that would further my argument about exaggerated
appearance of black lines.  (skipped/unused pixels)

 If not - it still does not consider the different look no matter what.



While this is true, they were not drawn with a malfunctioning display in mind.  In fact, some graphics were so meticulously planned to take advantage of the way CRTs work that anything but a properly functioning display would cause the graphic to turn to "mud", not terribly unlike that representation of the Turbo car you are showing.


 The pic is a jpeg in magnification.   At regular distance, and in person,  the monitor
looks pretty darn good.   

 I can dig up Tons of arcade photos of real machines that show how much
color variance difference there is between svga and an  arcade CRT.
Simulated lines do not capture that difference at all.



 Now, we can simulate this look using various methods... however, it will have
to be much more complex than some stupid Overlay effect.    We know that if we take a picture of an arcade monitor, and or vector..  we can then view them on our
pc monitor and they look accurate.  Even at fairly low resolutions compared to the
supposed ridiculously high res that you THINK you need to pull it off.   At
a mere 1024*768,  you can view an arcade pic full screen and have it look
very authentic. 

 The extreme would be a raytrace routine that would render the shadowmask
and the phosphors and calculate all the light rays bouncing around.. then
render that and scale it to the correct size. 

 However, that would take way too much processing power to do on the fly. 
A step seeming more achievable,  would be to create a ruleset routine of how to
alter the pixels color and brightness depending on its nearest neighbors..  as well
as other factors too.   It would then take the high res drawing and again,
scale it to the resolution needed.  (probably no less than 1024*768)


 My biggest point,  is that simply overlaying some dark lines over a
picture does not make it look anything like a true arcade display.

 Also.. that newly made monitors made have been altered to the point where
they really do not match the look of the original monitor when it was new.

 There is a market, for a device or software solution that re-creates that
arcade quality look on a PC monitor or LCD.   Especially with CRTs being expensive,
bulky, electric prices rising,  EMF radiation,  and finally, CRTs being phased out.