Correcting 480i overscan on a ATI DVI / component-out dongle

[Timstuff]

NOTE: I briefly considered posting this in the Monitor / Video forum, but I concluded that this was more of a software / driver issue, so I figured I'd be best off posting it here.

A week or two ago, I went and ordered a component cable dongle for my Radeon 9800, with the intention of using it in my arcade machine (I'm using a 20" SDTV for my monitor). The picture quality was very sharp, but unfortunately, I had some serious overscan problems. The Windows task bar nearly disappeared off the screen, and in a game like Mortal Kombat II, the upper half of the health bars and timer would be completely off screen.

I went into the Catalyst Control Center to see if the overscan could be adjusted like with an S-Video or Composite cable, but I had no luck. For now, the only 480i picture I can get over component cables is an overscanned one. I switched back to using an S-Video / Composite cable (my TV has no S-Video jack), but I really do miss the clarity that component out offered since it was nearly "arcade perfect," and composite most certainly is not.

So, does anyone know of a way to adjust the overscan on a 480i image over component cables? I've done a little googling on the subject, but I had trouble finding anything conclusive. Thanks in advance!

[Timstuff]

w00t! Today, I decided I'd give the dongle another try, but this time I made sure to download the Omega drivers for my Radeon. Unlike the official CCC, the Omega catalyst controls let you automatically optimize a screen, even if it's just a 480i TV. I did just that, and it completely fixed the overscan problem! Now games look absolutely friggin' gorgeous. The colors are increadibly bright and vivid, and it'd take a well trained eye to spot notice a difference with a real arcade monitor in terms of clarity.

[Ummon]

Cool. I was going to suggest setting the desktop to 640x432, as this is what TOK for example has done, but it's nice those drivers have such a feature.

[Timstuff]

Yeah, that works too. I do lose some pixels with NullDC when I run it over component video, but it's not even noticeable in the games I tested.

[rdowdy95]

Cool. I was going to suggest setting the desktop to 640x432, as this is what TOK for example has done, but it's nice those drivers have such a feature.

How do you set the desktop to 640x432 in windows.  Also is there a way to do that in MAME so I can get rid of overscan on some games?

[Ummon]

I think TOK uses MaLa, which has such a feature built-in and this cascades down to Mame if you have 'resolution' in 'default options' set to 'auto'. That's what he told me anyways.

[TOK]

Ummon had it right... I set a custom res in MaLa, so my Windows desktop is slightly overscaned but once the front end loads everything is perfect. My setup is on a 27" TV mounted vertically and never used for any regular Windows tasks so the desktop overscan isn't an issue for me.

[TheManuel]

Timstuff:

Do the red colors look correct?
I have a 9550 running through the dongle and the red color looks orange.  I have tried to fix it by adjusting even from within the service menu of the TV but I only end up messing up other colors.
This is true also of the S-video output.

It's driving me crazy... 

[jWin]

I have always had bad luck with the color red over ATI Component cable,  but what annoyed me more with the ATI Dongle was screen flickering/jitter,   using a newer ATI card that uses one of those svid->component cables allows flicker adjustments however, not sure if the ATI Dongle has that feature yet in the software.

Elena's stage in Street Fighter III Third Strike looks awful on my screen since its 99% red.

[TheManuel]

 I have only had problems with flickering when I set the screen resolution to 320x240 which I have only done for testing since it squishes the image into a small area of the screen rather than scaling the output to fill the whole TV screen which is one of my main complains about TV output.

As for the innacurate red color, I  arrived at some sort of happy medium.  I reverted everything in the service menu to where it was initially and from there simply reduced the red gain until it looked a little less orange.  It tends to go to pink but I was able to find a tone I could live with.
Then, from the TV's normal picture menu, I moved the tint control around a bit to where everything looked best to me.  Lastly, the color control is key.  If you go too high, then red bleeds out of everything (try Ms Pacman) but if you cut it too much, greens fade (look at title screen of Samurai Shodown).  You will have to settle for a compromise between these two issues.

If you play with it, let me know how it goes.

[Ummon]

I've found that any type of unit that has color controls is potentially problematic for the same reason I think audio units with integrated EQs are. Arcade monitors seem to have the purest colors because there is nothing in-between the source and the tube. Of course, TVs aren't (at least yet) designed with computer sources in mind where all this stuff can be, more cleanly I think, determined by software.