Questions about my "arcade" monitor and AVGA video card

[mamenewb100]

Well I'm pretty disappointed after discovering all the critical errors I've made already in the process of building a new arcade cabinet.

As you can probably guess by my screen name, I'm new to this process but have a great background in computers. The most crucial error might have been ordering the 29" Makvision (31 Khz) Arcade Monitor. Now there was allot of confusion by me about the whole 15 Khz thing people were talking about. Before I ordered the monitor I figured it just gave you some extra scanlines and was more compatible with the older arcade games. I did NOT research enough to find out that 31 khz was not even capable of low resolutions. This really bummed me out and made me somewhat upset with XArcade where I ordered the monitor from because they were pushing this monitor as "Highly recommended for MAME use" over the other Tri-Mode monitor they were selling that had 15, 25 and 31 Khz modes. I have the feeling they were just trying to sell the monitor as everyone on forums like this says to stay far away from 31 Khz. However, I think people that say buying a 31 Khz Arcade monitor is no different than buying a PC monitor is very wrong. It still has MUCH larger pixels per inch than a PC CRT. Mine has .79 DPI compared to the very fine .22 or so that PCs use. So games will still look much better than a PC CRT, just without the thick scanlines of a 15 Khz arcade monitor. Which I don't really care for anyway. I'm looking for good image quality above all.

Now ultimately this was my fault for not doing enough research. I originally decided to go with the 31 Khz model because it had a higher res of 800x600 vs the 640x480 of the Tri-Mode version. I planned on playing some PC games and newer 31 Khz arcade games as well if possible and didn't really like the sound of having to switch between the modes. The higher res does make it easier to fit windows on the screen but not enough to outweigh the disadvantages of not having 15 Khz. However I could not return the monitor because I would have had to pay shipping charges for sending it back AND charges for the replacement monitor. On top of having to wait a couple weeks or so to get the other one back.  

So no big deal. I'd been reading about GroovyMame and how you can double the resolution of a 15 Khz game to match a 31 Khz display without having to stretch the image. Well, here is Mistake Number #2. I bought the ArcadeVGA that everyone was buzzing about. I was thinking it would be customizable and would work well even with a 31 Khz display. Also I read how Groovymame worked well with ATI cards and I thought I'd be able to get a really sharp image by doubling the old games with VMMaker. Not so much.. after researching once again further AFTER the purchase. Apparently you can't change video modes other than the ones that are included with AVGA I'm told? It's still hard to believe that you can't somehow treat it like a regular card but I guess the firmware is locked?

So it looks like my only option now may be to buy a regular ATI video card and try to sell my AVGA. That sucks because it still has some features that I like about it like keeping the signal from going out-of-range on bootup and the games SEEM to look fine compared to LCD anyway. But I'm assuming most games are stretched from 320x240 to 640x480 since my vertical frequency is twice that of the older games.

So a couple questions for people that are using 31 Khz pixel doubling: Is it a OMG WOW difference compared to plain 31 Khz image or do you have to look close to notice(doubtful). And what ATI video card would work best with a Windows 7 64-Bit, Hyperspin, GroovyMame type of setup?

[ed12]

hi
well i do not know about u
but i have used 15khz s/w found here on our fourms
all type's of monitor's and game config's
work's like a dream
even added it to gobal vr pga as a option
give it a go

ed

[MonMotha]

Yeah, I don't know why they push that high res model so hard over the low res one.  Almost nothing actually uses 800x600, and the "low res" one can handle a lot more commonly desired emulation scenarios.

The dot pitch is pretty coarse, but it works well at lower resolutions.  640x480 on a monitor that size with PC CRT dot pitch would look pretty grainy and blocky, but it looks really, really nice at the coarser dot pitch used by TV tubes (and shared by conventional arcade monitors).  Even 320x240 looks decent.  You do run into diminishing returns above 640x480, though, which also makes the 800x600 support a bit superfluous.  The coarse dot pitch of the tube starts to become limiting at that point.

I don't remember the specs...does this thing support 120Hz refresh?  I kinda doubt it, but if it does, you can do the double framerate trick to get fully native video on it (though it won't flicker like you may be used to).  If it doesn't, you'll have to do doublescan (draw each scanline twice).  It doesn't look terrible, but it doesn't look perfectly correct either - the phosphor effects will still be close, but the scanlines will be wrong (there will be twice as many).  You don't have the signal res (or screen dot pitch) to do the HLSL type effects people use on high res LCDs to emulate scanlines and phosphor effects.

[mamenewb100]

I don't remember the specs...does this thing support 120Hz refresh?  I kinda doubt it, but if it does, you can do the double framerate trick to get fully native video on it (though it won't flicker like you may be used to).  If it doesn't, you'll have to do doublescan (draw each scanline twice).  It doesn't look terrible, but it doesn't look perfectly correct either - the phosphor effects will still be close, but the scanlines will be wrong (there will be twice as many).  You don't have the signal res (or screen dot pitch) to do the HLSL type effects people use on high res LCDs to emulate scanlines and phosphor effects.

I think the max refresh is about 90 Hz. I'm not real big into scanlines and being 100% accurate. So as long as there is no real loss in image quality, then I'm fine with it. Are you saying there will actually be MORE scanlines, so it will look even more old school? I was thinking it would be the opposite being at a higher res.

Is it correct that there is no possible way to do the doublescan effect on AVGA?

[MonMotha]

There will be "too many" scanlines.  Each original row of pixels (a scanline) will be drawn twice, and there will be a somewhat noticeable gap in between them.  It certainly doesn't look "more authentic", but you may not find it particularly objectionable.  Since both scanlines are identical, they tend to "bleed" together.

I think you can do doublescan on the AVGA with the "trisync utility", but I don't know much about it.

With Soft15k, bang the "Install 31k" button.  I don't recall everything that dumps in the driver modepool, but it should give you at least some options.

If concocting your own modeline from a known-good 15k mode, double the pixel clock (first number), leave all the other numbers the same, and add "Doublescan" to the list of flags.  Should work on Linux/X11.  I dunno if Soft15k (which uses the same modeline format) will honor it or not.

I'm sure somebody has worked out how to do this on Windows somewhere.  Unfortunately, getting very specific graphics modes on Windows is difficult or even impossible, depending on what mode you want and what hardware/drivers you have.

[mamenewb100]

Interesting. Hadn't tried Soft 15 yet because I figured it was only for 15 Khz displays. I'll try this out later.

It would be nice to try Linux. Problem is I fell in love with Hyperspin and of course it's Windows only.