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Trick with using PC CRT
RandyT:
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
ahofle:
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:
--- Quote from: ahofle on July 11, 2008, 03:30:26 pm ---
--- Quote from: megaultrasuper 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.
--- End quote ---
Isn't that what the OP is suggesting? (640x480 = 31khz)
--- End quote ---
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.
RoomTenONine:
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.
RayB:
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):
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