Scanlines On Screen?

[mysql101]

I'm sure someone's mentioned this before, but I couldn't find any threads specifically about the subject ...

Anyone notice what looks like scanlines or interlaced output on the gp2x screen?

After watching an entire episode of Family Guy I came to see what was going on...

If I hold the unit perfectly still, the display looks pretty good. Images are crisp and clean. However, if I move the unit up and down while watching the video I will see every other line on the screen displaying which causes the video to look like it has every other line missing or every other line to appear darker.

Anyone know what's going on and if this is a perm thing?

 

[TelcoLou]

Yeah, it's 'normal'.

Mine started showing these scanlines after the 1.01 upgrade. Hopefully, the next one will fix them.

 

[mysql101]

Mine has been like this in 1.0, and I just did the upgrade, still the same.

The scanlines and the screen flickers are the two gripes I have. Batt life seems great, no dead pixels on screen...

 

[mysql101]

actually you might be right, I think the problem is a bit worse since the upgrade.

 

[matt goode]

Is their any major reason to upgrade to 1.1? I was just wondering if i should when mine arrives,
Matt

 

[TelcoLou]

Is their any major reason to upgrade to 1.1? I was just wondering if i should when mine arrives,
Matt

​

Um ... it turns off the Red low battery indicator LED

It actually improved the contrast, as far as I can tell; it was a bit too bright before.

 

[matt goode]

Aah i see, so what, was the battery Lcd on permanently before?

 

[TelcoLou]

Aah i see, so what, was the battery Lcd on permanently before?

​

Yep. Though for now, it's just turned off ... it won't come on when the batteries are low .. just a band-aid so to speak.

 

[matt goode]

It will be nice when its all working cant wait

 

[Quiest]

I got the scanlines too. ED said it`s a timing error with the display (whatever that means, I don`t know). But it will be fixed in future FW updates.

 

[foft]

Would be nice to have a patch to fix the display. Because its using this crappy timing emulators skip frames and interlace effects don't work properly. e.g. when in Atari800 they are doing "full colour pictures" using 2 frames. i.e. half the frames don't get displayed!

Mark

 

[Tron04]

it must be a software issue, since in testmode (when pure colors are shown", there is no scanlines at all. Just the pure colors. No flickering.
EvilDragon told me that the MegaDrive Emulator also has NO scanlines.
I would like to see that myself.

 

[reallynotnick]

it must be a software issue at since in testmode (when pure colors are shown", there is no scanlines at all. Just the pure colors.

​

LOL, is it even possible to have scanlines on a solid color? We are talking about how like TV's are interlaced right? Like on static images they short of shudder.

If it is some one has to prove it to me.

 

[Steve Warner]

LOL, is it even possible to have scanlines on a solid color? We are talking about how like TV's are interlaced right? Like on static images they short of shudder.

Static images on a television shudder because each frame of interlaced video consists of two separate images woven together (hence, interlaced). Interlacing is a phenomena unique to TV and comes from its early days when the hardware wasn't capable of drawing an entire full frame at 30fps (NTSC). As a result, the frames were split into odd and even fields. The TV draws the odd fields first, then the even ones. It does this 60 times per second (NTSC) and 50 times per second (PAL).

When you see an image shudder, it's because you're paused on one frame, but within that one frame, you're seeing 2 half-frame fielded images woven together.

Television sets have avery low resolution. Scanlines are simply the magnification of the odd and even fields. But since computer monitors display footage in progressive frames (rather than interlaced ones like TVs), you won't get scanlines unless there's a software problem.

It's possible to get scanlines on a solid color, but again, only under two conditions. The first is that you're displaying the solid color on a regular television and you get close to the screen. The second is if you're using a computer display and you've intentionally put the scanlines there (for effect) or you've got a software problem.

My guess is that any scanlines on the GP2X are simply a firmware issue.

 

[Tron04]

I did some test pictures in png format with solid colors and watched them very closely on the gp2x.
For this sake I tilted the gp2x by 90 degrees (Portrait Format).
When viewing the pictures this way you can see the scanlines VERY clearly. Just let your eyes wander slowly from left to right and they will "snap-in" with the scanline frequency. Nice scrolling effect...
What I have found out so far:
Most of the colors on the gp2x show the scanline effect and I am talking of pictures with only one color.

But there are colors without ANY flicker:
pure white
pure yellow
pure turquoise
pure red
pure green
pure blue (not sure here..)

 

[Mr. Anderson]

it must be a software issue at since in testmode (when pure colors are shown", there is no scanlines at all. Just the pure colors. No flickering.
EvilDragon told me that the MegaDrive Emulator also has NO scanlines.
I would like to see that myself.

​

Yep! That's what I think too. The Testmode "images" look perfect, no scanlines, no flicker, no moving waves, nothing. The problem is there, when a special type of color combination happens, it's sure a problem of the firmware..

 

[Tron04]

I would tell it the other way round:
Most of the colors possible (I would say about 95%) are suspectible to scanline-flicker. Only the pure colors do not have the problem. I did some test-png files with burst color spectrums on it and only a few areas didn't flicker (the ones near the pure colors).

Get the Test-Suite.Zip File here: http://rapidshare.de/files/8688674/Scan-Test.zip.html
and draw your own conclusions.
Remember to tilt the gp2x by 90 degrees to better see the effect.

If it is a firmware issue, then all colors should have the scanline problem. But from what I have seen so far, the problem seems to be much more complicated.
I hope I am wrong...

 

[Mr. Anderson]

scanlines and the "waving problem" I have sometimes, are all only happening because of color combinations. The LCD has a wrong timing from what I've heard. So a completely one colored display simply can't show scanlines. I guess the T-Mode from GPH is the best test for your display, if it's really broken, or not...

 

[Tron04]

Sorry Mr. Anderson: Not True.
I made several Test Pictures with only one color (get archive above) and they do flicker!
For Example: Pure White -> No flicker
Grey 50% -> flickers...

 

[Mr. Anderson]

I could download your proggy, however it would be of no use to me(referring to the first line of my sig).

50% grey you say? Hmm.. strange, but still this looks like the firmware is the main problem. Could it be that it can only display the 8Bit VGA pallete correctly?