Why is Component Video Flickering

[Skadar]

I'm using a JVC televsion, a Sapphire Radeon 9600, and the ATI DVI>Component adapter to get a really sharp picture display.  However, the refresh rates appears to be very low.  The flickering bothers me.

When I plug in and use S-video, the picture quality is worse but there is no flickering at all.

Can any video experts explain what is going on here?  ...and maybe offer a solution?   

Thanks.

[Jess--]

the flickering is most likely caused by interlacing, try running at a lower resolution.

when you are using the svideo output you will find that there is a setting on your display properties ( i think marked up as flicker reduction or something similar) adjusting this will allow you to get a balance between the sharpest picture possible with svideo (with flicker) or a slightly fuzzy svideo picture with no flicker or reduced flicker.

[Veinman]

I got the flicker on my ATI 9800 pro on a similar setup, but it was only in windows. mamewah and emus ran perfectly.

[Barkuti]

Displaying "hi-res" (480/600 lines) at 15.7ish KHz scan rate using component or RGB input means you're interlacing the image; you're seeing standalone lines flickering because they only get refreshed on even or odd field rasterizations (effective frame refresh rate is half). There's no way to correct this, it's not a problem, it's a "feature" 

The reason for your S-video looking less flickery is your videocard circuitry, which applies some sort of trick/filter or whatever technique to reduce flicker (I don't know more about), at the cost of blurriness, as pointed out by Jess--. But S-video has nothing to do with RGB or component, the latter ones are WAY better. S-video is TV-like, 525/625 lines and 60/50 Hz interlaced video. It will look like crap when compared to native resolution progressive RGB or component.

So the flicker is likely to be noticed whenever you have to use interlaced display (for example in typical 640x480 or 800x600 desktop resolutions).

Cheers

[Skadar]

So the flicker is likely to be noticed whenever you have to use interlaced display (for example in typical 640x480 or 800x600 desktop resolutions).

Thanks very much for the explanation.  I don't mind the flicker when I'm in Windows because I really don't care... I'm just using Windows temporarily to get something launched or to change a setting.

However, I *am* noticing the flicker while in-game (MAME) and it kind of bugs me.  Currently I am forcing MAME to run at 640x480 resolution.  I tried running at 800x600, but 25% of the image was off the edge of the screen and I have no way (that I know of) to solve that problem.

I've selected 480i for my component video output from my computer (on the ATI Dongle).  I tried 1080i just for the heck of it and it didn't work.

MAME 99b
MAMEWah 1.61
JVC AV-27530 27" non-HDTV
Sapphire Radeon 9600 Atlantis w/ S-video and DVI outputs
Clone ATI DVI>Component video dongle
Latest ATI Catalyst drivers (not sure that this even matters though)

Is there any setting (whether in MAME, video drivers, etc) that could reduce the appearance of the flicker?

[Barkuti]

Mmmm, if you're forcing MAME to run at 640x480, you're obviously using interlaced video. Technically speaking, you're using 525 lines interlaced, 60 Hz field refresh rate (30 Hz frame refresh), 15.75 KHz horizontal scan rate. Any given mode uses extra lines not used for the picture: that provides time for the vertical retrace of the monitor, image adjustment/displacement and all that stuff.

You need to run MAME on proper progressive low resolution modes, and unscaled video (do not use stretching!). Read The Monitor FAQ. The last post contains the most useful information for you.
Additionally, as you're using a TV your video modes will more or less suffer from overscanning (all TV's overscan). You'll need access to the TV's service menu for image size adjustments. Search the web for related info/service manuals.

Cheers

[Popcorrin]

You need to run MAME on proper progressive low resolution modes, and unscaled video (do not use stretching!). Read The Monitor FAQ. The last post contains the most useful information for you.

Cheers

You do realize he is using a television and not an arcade monitor.  These suggestions really won't do him any good.

[Barkuti]

You need to run MAME on proper progressive low resolution modes, and unscaled video (do not use stretching!). Read The Monitor FAQ. The last post contains the most useful information for you.

Cheers

You do realize he is using a television and not an arcade monitor.  These suggestions really won't do him any good.

Yes I know that. He's using a TV, hence the reason for my suggestions. A TV is basically like a standard CGA arcade monitor with TV system, audio & input decoding circuits (plus speakers, connectors, enclosure, etc.). When driven through direct component inputs or RGB (SCART equipped sets), they behave exactly like a CGA arcade monitor; the service menu of the device holds the picture adjustment stuff.

Believe me I know what I'm speaking of. I myself built a custom transportable PC equipped with an ArcadeVGA and assembled inside the very light Antec Super LanBoy, modded with tons of lights . The whole thing wheighs just 22 pounds/10 kg. The case has a tiny drawer I use to carry a laptop mouse. I also made a custom VGA to SCART RGB cable (video over shielded cat 5e cable), including the audio output from the PC, so I can use any SCART driven TV as the comp's monitor. The image quality is just the real thing, AWESOME. Period. Playing movies on it provides unbeatable results also.

Hope the info helps.

Cheers

[divemaster127]

Sometimes the flickering is due to the tv you might try a different one
thanks
divemaster

[Popcorrin]

You need to run MAME on proper progressive low resolution modes, and unscaled video (do not use stretching!). Read The Monitor FAQ. The last post contains the most useful information for you.

Cheers

You do realize he is using a television and not an arcade monitor.

[Barkuti]

You European televisions are different.  Here in the U.S. we don't have Scart driven TV's.   Component input, while being close, is not the same thing as RGB.  So the suggestions you gave him really won't do him too much good with the TV he has.

Mmm, sure? The component to RGB video conversion circuitry has nothing to do with scan rates, interlaced/proggressive scanning or whatever. I don't really know (some tech info would be of help), but if what you say is true it would imply that those YUV->RGB circuitry expects the signal in a given particular format (like 60 Hz interlaced 525 line video), but that doesn't makes sense to me. All it takes is obtaining RGB signals from the YUV differentials and HV synchronization signals from the Y component (SCART TV's take composite sync and separate it into HV signaling).

Can you shed some additional light here?

Cheers

[Abomination]

Hey me and skadar have the exact same setup and I'm having the exact same issues but I set mine up the same way he did.  There is so many options between the TV's settings, windows, the ATI card, ATI DVI-I to component adapter, and powerstrip I'm just overwhelmed. 

That flickering is damned annoying and there has to be a way to fix it, does anyone know what setting my dvi-i adapter should be at, there are dip switches for different resolutions and atm the 480i is the setting I'm using but not sure if thats the right one.  Also what refresh rate should I use, I have yet to see a difference between 30hz and 60hz.  Anyone that could walk me through this a bit?

[Skadar]

Also what refresh rate should I use, I have yet to see a difference between 30hz and 60hz.  Anyone that could walk me through this a bit?

NOTE: When I talk about display I'm talking exclusively about display within MAME.  I don't care about the Windows display quality.

My knowledge on the video side is severly lacking and I found the same thing as you... no apparent difference between 30Hz and 60Hz.  But I think I am beginning to understand why.  Here's what I think... anyone let me know if I'm wrong.

I understand now *what* the flickering is.  It is due to the fact that every other line is being redrawn with each screen refresh.  Therefore, at 60Hz, each line is only being redrawn every other refresh, giving you an overall effective refresh rate of 30Hz.

Not sure why, though... that selecting 30Hz won't give you an overall refresh of 15Hz though.

But I digress.  This isn't our main problem.  I have a feeling though, that there is no answer here for us.  I think that by using non-HDTV, non-progressive scan televisions, there is no way around the flickering issue.  Am I right?

The only tinkering that actually affects my video quality are the mame.ini video settings.  But none of these alter the flickering. 

[Abomination]

so would an HDTV fix this?  I have in my house now a sony trinitron 27" HDTV.  The flicker is annoying enough that I may use it but destroying a 600 dollar TV doesnt really appeal to me all that much (I would have to take the case off speakers are on the side)

[StephenH]

I would try turning off double screen size, and setting MAME to a low resolution (below 300 vertical lines).   Also, I would try changing the triple buffering settings.

As for using a HDTV, I would try setting it to 480P or 720P and see what happens.   The "Progressive Scan Modes" are not interlaced, and therefore less flickery.  Modes than end in an i (480i, 1080i, etc) are interlaced, and more flickery.  The other thing is that some HDTVs are 16:9 ratio, which would probably look bad in MAME for many games.  However, some games (such as CPS2 games, are essentially 16:9, and would look very good on a 16:9 TV.  There are commands in MAME to force the aspect ratio.

[wpcmame]

try

mame game -r 640x480 -cs full -d3d -flt 0

[Skadar]

Just tried switching back to S-video because the flicker was bothering me.

Wow!  I couldn't stand using S-video.  Switched back to component after a few minutes.

Component, flickering and all, is worlds better.

[NinjaGumby]

I read in another post (not sure if it was a mistake) that you need to set the ATI->Component adapter to 480p.  Have you tried that?

Also, you should give a try at AdvanceMame to see if it would solve the problem.

I'm interested in your result since I was planning on buying this same TV, but might buy a 25" arcade monitor if it doesn't work really good for you!

[AndyWarne]

The problem can be summed up with a simple equation:
Vertical Refresh rate = Horizontal scan rate / Number of vertical lines.
If we fix the Vertical refresh at 60, and the Horizontal at 15Khz this gives 250 lines. This is why the picture using an arcadeVGA card to a SCART TV is flicker-free, as it is displaying a non-interlaced picture at around 250 lines.
A TV fed with a normal VGA card displays native TV resolution, 500 lines (or thereabouts) and therefore must be interlaced as two frames of approx 250 lines, hence flicker.
Some TVs, however, do have inbuilt methods of reducing flicker, such as scanning at 120Hz and this might be why in some modes it appears flicker-free.
Andy

[Skadar]

Hmmm... this TV does have extensive service menu options.  I need to dig into them to see if there is anything I can tweak on the TV-side of things.