How badly is interlaced supposed to flicker?

[krick]

I've got a Hantarex Polo 25 15KHz arcade monitor in my MAME cabinet.

I've been trying to set up a new front-end and I wanted to give HyperSpin a try, however it seems that it only works at 800x600 resolution.  I know that the interlaced resolutions are supposed to flicker, but on my monitor 640x480 and 800x600 flicker so bad, it's painful to look at for more than a few seconds.

Is this normal?  If not, is it something that could be fixed with a cap kit?

[MonMotha]

Depending on the individual and monitor in use, it ranges from "not too bad, but noticeable if you're looking for it" to "immediate headache".  Some people are just more sensitive to it than others, but some monitors have short decay times or just plain don't handle interlaced inputs correctly at all.

640x480 should look about the same as American television, but the sharper lines common in PC graphics and allowed by the RGB signal (rather than TV) will accentuate the problem a bit.  800x600 will look more like European television which has more flicker but higher resolution (and nobody can agree on which is better).

[krick]

Strangely, on my monitor, 720x480 looks fantastic.  I can barely tell that it's even interlaced.  However 640x480 makes my eyes bleed.

I really don't know how one interlaced resolution can look so good and another look so bad.

[MonMotha]

Those should look effectively identical.  The monitor actually has no idea what horizontal resolution you're feeding it (some very fancy digital monitors excluded).  All it knows are the refresh rates and number of lines.

Are you using Soft15kHz?  It uses some subtly different timings between 720x480 and 640x480, and the 720 version is more "friendly" to most monitors.  In fact, the default 640x480 timings don't even work many arcade monitors I've tried it with (though the JPAC seems to patch it up for you, if you're using one), especially when using composite sync.

The 800x600 15kHz resolution will be very flickery.  The vertical refresh rate is only about 50Hz, much like European TV, so if you're used to American TV, be prepared for some headaches.

[krick]

I'm currently using an ArcadeVGA3000 with the Ultimarc Windows XP x64 drivers.

I am using a JPAC as well.

On my computer, 640x480 and 800x600 both look almost the same in terms of awfulness.

720x480 looks incredible in comparison.  Like I said, it's almost hard to tell it's interlaced unless I'm looking at small high-contrast text.


I'm thinking about trying an ATI HD 4550 with Calamity's modified ATI drivers this weekend to see if it looks any different.

Maybe I can isolate whether it's a monitor, video card, or driver problem.  I wouldn't be surprised if it was my monitor, but I'm just baffled as to why 720x480 and 640x480 look so different.

[MonMotha]

Sorry, I don't know what the ArcadeVGA does in terms of exact timings.  You might try asking Andy.

[krick]

I did some testing this weekend and I discovered something odd.

If I uninstall the drivers, the ArcadeVGA3000 looks great at 640x480.  If I re-install the drivers, it looks bad again.

I'm using the Ultimarc Windows XP x64 drivers, and I don't know if it's specific to this version of drivers or not.

I may need to dig out my Windows 7 installation and see if the issue is there as well.

I tried a Sapphire ATI HD 4550 with Calamity's patched drivers, and interlaced resolutions look good as well, so I'm positive that it's not my monitor anymore.

I need to play around with Ultimarc's ArcadePerfect Utility and see if it makes any difference.

[krick]

I reported the issue to Andy at Ultimarc and he released an updated XP x64 driver that fixes the problem with 800x600 and 640x480.  Now, my interlaced resolutions look really good.  Case closed!

[Gray_Area]

I'm betting the original resolutions were at less than 60hz, as MonMotha was suggesting.

[krick]

The problem was totally in the ArcadeVGA driver.  It didn't have anything to do with the refresh rate at all.  It had something to do with the screen geometry.  When I use the ArcadePerfect utility from the Ultimarc site, simply bumping up the vertical height +1 will completely fix 640x480 or 800x600 so they no longer look terrible.  However to make the change permanent, Andy had to change the geometry in the driver itself.

The giveaway was that 720x480 looked great.  When I compared it against 640x480 using ArcadePerfect, I noticed that the vertical height parameter was one less on 640x480, even though they should be the same.

[kalars123]

where are these updated driver's you speak of? the only driver's he has even on the hidden driver's page are the same one's that havn't been touched since 2010

[krick]

where are these updated driver's you speak of? the only driver's he has even on the hidden driver's page are the same one's that havn't been touched since 2010

I can't speak for any of the other drivers, but the XP x64 driver on this page has definitely been modified...

http://www.ultimarc.com/avgadrivers.html

I have the original download from when I first installed my AVGA3000 and when I do a diff against the current download using BeyondCompare, and ignoring timestamps, there is one binary file that has been changed.  If you want me to post a screenshot of the diff for proof, let me know.  None of the driver version numbers have been changed as far as I know.

With the old driver 640x480 interlaced and 800x600 interlaced look terrible. With the new driver, those two resolutions look really good.  So whatever Andy changed in that one file fixes the geometry problem with those two interlaced resolutions.

[kalars123]

ahh there in lies the black sheep xp 64 lol, i'm useing win7 64 and he hasn't changed anything

[krick]

I'm not sure if the issue exists in Windows 7, though Andy implied that he was going to apply the fix to "other" drivers besides the XP x64 ones.

It's really easy to tell if you have the issue.  Just compare 720x480 interlaced to 640x480 interlaced.  They should have the same visual quality.  If 640x480 looks markedly worse, then the problem is present in the Windows 7 drivers too.

Speaking of Windows 7, have you encountered any problems with running vector games?  I made the decision to switch from Windows 7 to XP x64 because Asteroids ran at 50% speed on Windows 7.  It turns out that windows reports the refresh rate at 1/2 what it should be for interlaced resolutions.  When GroovyMAME syncs to the refresh rate, Asteroids (and other games using interlaced resolutions) run at half-speed.

For me, this was a deal-breaker and Win7 had to go.

[kalars123]

i don't have any interlaced resolution's going, i use the next closest non interlaced the whole direct draw issue where you can't go from an interlaced res "desktop" to a non interlaced res "game" was enophe for me to give up that little bit of quality

[krick]

Hmmm... what resolution do you run Asteroids and Tempest at?
What about "19xx" and "xevi3dg"?

[kalars123]

i couldn't tell you off the top of my head i'm not near my machine, but i know with vertical games i have hw stretch on,auto res,auto,refresh,force AR 4:3, and it works fairly well, the text in the games isn't always great but they display decently, when i was trying to run native res's on my horizontal monitor they games looked great, but the screen would go well above and below the physical display area, and made it nearly impossible to play, where as now it's playable but the display isn't great.