Scanlines Again

[Radek]

I complained of this on my gp32's and called it flickering and people said I was imagining it.

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Well... most the TV sets have an interlacing and do flicker unless there is scan doubling circuity (so called 100/120Hz TVs). But many people will not see this phenomena anyway yet of course it doesn't mean it isn't existing.

There also very visible moira and steps for some picture because vertical resolution isn't exactly high on TV. I once asked someone if he had been seeing these artifacts too and he just looked at me like I was some kind of retard.

 

[EvilDragon]

Well, LCDs don't interlace. TVs do.
LCDs should be pretty stable.
It's definately not normal what we see here. Or do you see scanlines on your computer TFTs?

AFAIR only the BLU+ had scanlines, not the BLU and not the NLU nor FLU.

Question is: Why does the gp2x interlace?
My guess is: As they planned TV Out support, they probably used a Linux graphics driver designed for TV Output, so they just need to redirect their output to the TV Out when somebody is using the TV Out cable.
As TVs use interlacing, the data sent to the LCD is interlaced - therefore causing odd effects like scanlines.

What supports my theory:
If you run Frodo, Vice or DrMD in TV Out Mode, you see two pictures of the emulator on the TV screen:
One at the top and another one at the bottom.
The one on at the top shows all the ODD lines, whereas the one at the bottom shows all the EVEN lines.

So, Vice, DrMD and Frodo are DEFINATELY using interlaced graphics!

 

[Shikaku]

Or do you see scanlines on your computer TFTs?

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I don't see scanlines or the like, but I see GHOSTING.

I prefer CRT monitors, thank you...

 

[jmetal88]

AFAIR only the BLU+ had scanlines, not the BLU and not the NLU nor FLU.

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The BLU+ and the normal BLU did, however, the normal BLU's screen being rotated 90 degrees, they were vertical, and hard to see, although if you played it in the sunlight it did not take any effort to spot them. I never noticed them on my NLU, but perhaps that's because the LCD was made to look good using reflected light.

 

[paeryn]

Question is: Why does the gp2x interlace?
My guess is: As they planned TV Out support, they probably used a Linux graphics driver designed for TV Output, so they just need to redirect their output to the TV Out when somebody is using the TV Out cable.

Nope, in normal mode the MMSP is set to do progressive. The signal does however go via the CX chip which might be messing things up.

What supports my theory:
If you run Frodo, Vice or DrMD in TV Out Mode, you see two pictures of the emulator on the TV screen:
One at the top and another one at the bottom.
The one on at the top shows all the ODD lines, whereas the one at the bottom shows all the EVEN lines.

So, Vice, DrMD and Frodo are DEFINATELY using interlaced graphics!

​

The problem with TVOut for the emulators is that the screen resolution is different. LCD mode is 320x240, TV is 720x576 (PAL) or 720x480 (NTSC). The emulators (and any other program) that don't take this into account (and the interlace difference) causes those problems.

Also, I have the specs for the LCD - other than GPH having the clock rate slightly off I can't see anything wrong. All that does is give faint diagonal lines that creep across the screen. I'm looking into how the CX is set up, it seems to be in a default mode for LCD.

 

[chris_r]

Yes, i've noticed the GP32 does it too, turn it on its side

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I just looked at my 32 and I didn't see any scanlines at all. I'm starting to think there's something seriously wrong. Looking at my 2x for too long now makes me feel physically sick because my eyes start to hurt.

 

[Dr Cain]

Question is: Why does the gp2x interlace?
My guess is: As they planned TV Out support, they probably used a Linux graphics driver designed for TV Output, so they just need to redirect their output to the TV Out when somebody is using the TV Out cable.

Nope, in normal mode the MMSP is set to do progressive. The signal does however go via the CX chip which might be messing things up.

What supports my theory:
If you run Frodo, Vice or DrMD in TV Out Mode, you see two pictures of the emulator on the TV screen:
One at the top and another one at the bottom.
The one on at the top shows all the ODD lines, whereas the one at the bottom shows all the EVEN lines.

So, Vice, DrMD and Frodo are DEFINATELY using interlaced graphics!

​

The problem with TVOut for the emulators is that the screen resolution is different. LCD mode is 320x240, TV is 720x576 (PAL) or 720x480 (NTSC). The emulators (and any other program) that don't take this into account (and the interlace difference) causes those problems.

Also, I have the specs for the LCD - other than GPH having the clock rate slightly off I can't see anything wrong. All that does is give faint diagonal lines that creep across the screen. I'm looking into how the CX is set up, it seems to be in a default mode for LCD.

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Sounds strange that they feed the lcd through the TV encoder, but makes sense..
Anyway, keep us posted on your progress on figuring this out.