Pandora Scaling

[christo930]

Is there anyone here who has actually used a Pandora (and can talk without breaking any NDA) and has seen the pandora emulate lower resolution systems like the Genesis? I noticed on my laptop that the screen only looks good at it's native resolution. Since the Pandora has a high res screen will there be black bars around the game that doesn't fill the full resolution? If it scales, does the scaling look good? I noticed on the GP2X when you scale up games that have lower resolution than the the gp2x screen it just doesn't look right (like gamegear for example). Does the Pandora's screen overcome this limitation of LCD screens?

Chris

 

[Pickle]

Is there anyone here who has actually used a Pandora (and can talk without breaking any NDA) and has seen the pandora emulate lower resolution systems like the Genesis? I noticed on my laptop that the screen only looks good at it's native resolution. Since the Pandora has a high res screen will there be black bars around the game that doesn't fill the full resolution? If it scales, does the scaling look good? I noticed on the GP2X when you scale up games that have lower resolution than the the gp2x screen it just doesn't look right (like gamegear for example). Does the Pandora's screen overcome this limitation of LCD screens?

Chris

If you want to keep a native scaling then you will have black bars i.e. 320x240 scaled to 640x480 will have a bar above and one below.
Scale it to fill the screen and you will have streaching and it wont look right. You could offset some of this by filtering, but we will have to see if Pandora could have enough power to do any filtering.

 

[Exophase]

Pandora will have FSAA (full-scene anti-aliasing) and anisotropic filtering (which implies bilinear filtering) in hardware. The PowerVR SGX whitepaper indicates the former, and the PowerVR overview paper indicates the latter for all their mobile chips.

If you're asking if it can do multiple resolutions natively then the answer is no, but nothing that I know of really can, much less any LCD. Even CRTs are composed of a fixed (yet very high resolution) set of pixels.

 

[Pickle]

Pandora will have FSAA (full-scene anti-aliasing) and anisotropic filtering (which implies bilinear filtering) in hardware. The PowerVR SGX whitepaper indicates the former, and the PowerVR overview paper indicates the latter for all their mobile chips.

If you're asking if it can do multiple resolutions natively then the answer is no, but nothing that I know of really can, much less any LCD. Even CRTs are composed of a fixed (yet very high resolution) set of pixels.

Duh, yeah im forgetting the GPU. Ive had a GP2X for too long.

 

[DaveC]

Is there anyone here who has actually used a Pandora (and can talk without breaking any NDA) and has seen the pandora emulate lower resolution systems like the Genesis? I noticed on my laptop that the screen only looks good at it's native resolution. Since the Pandora has a high res screen will there be black bars around the game that doesn't fill the full resolution? If it scales, does the scaling look good? I noticed on the GP2X when you scale up games that have lower resolution than the the gp2x screen it just doesn't look right (like gamegear for example). Does the Pandora's screen overcome this limitation of LCD screens?

Chris

You can't overcome limitations of LCD screens because they are fixed pixel. Every method has its advantages/drawbacks. For this reason emulators almost always give options of how to scale/not scale.

There a few ways you can do it.

Native resolution: Sharp but small (on Pandora due to the high res, looks fine on lower res systems like GP2X which uses this one alot).

Integer pixel "doubling": (Genesis 320 x 224 for example would double to 640 x 448) This will probably be a good tradeoff as you will get a sharp image and good image size comparable to what is on the GP2X now. The only disadvantage is that you would have a black border but that is no big deal for many emulated systems. This will basically look just like native resolution. A group of 4 pixels on the Pandora will be pretty much the same size as a single pixel on the Gp2X.

Fractional scale: This just takes the image and stretches to fill. You will get a bigger image but will get pixel distortion.

Fractional scale w/filter: Fills the screen and filters out the odd pixel distortion. The downside is that the image looks kind of blurry/fuzzy and reduces the contrast as it averages pixels.

As far as what people will like that is always subjective. I tend to like the integer option as it seems a good tradeoff and doesn't blurr. Since everyone is different though the emulator authors usually give you the obove options to choose from.

 

[christo930]

Pandora will have FSAA (full-scene anti-aliasing) and anisotropic filtering (which implies bilinear filtering) in hardware. The PowerVR SGX whitepaper indicates the former, and the PowerVR overview paper indicates the latter for all their mobile chips.

If you're asking if it can do multiple resolutions natively then the answer is no, but nothing that I know of really can, much less any LCD. Even CRTs are composed of a fixed (yet very high resolution) set of pixels.

I was just asking because I know there have been some advances in lcd lately (like the lcd used in the JXD 301), though I don't know much about it. It doesn't seem to affect crt's as mucch. Anyway, does it look good with the improvements you mention above? I know (at least on a crt) that the newer version of mame with full screen anti-aliasing look really good. I haven't tried mame on my laptop yet.

Chris

 

[Exophase]

I don't know, FSAA varies in implementation and there are usually quality levels. For bilinear, in my opinion, the higher a ratio you're scaling the better it looks (less fuzzy).

There are also some techniques that can be done at the expense of more hardware power, by blending the framebuffer at different offsets with multiple passes. These can give something inbetween bilinear and nearest neighbor. I don't know whether or not Pandora will be able to pull such a thing off.

 

[rokdcasbah]

If you're asking if it can do multiple resolutions natively then the answer is no, but nothing that I know of really can, much less any LCD. Even CRTs are composed of a fixed (yet very high resolution) set of pixels.

I think that B&W CRTs can have an arbitrary horizontal resolution (depending on how you measure, even fractional) up to the limit of the signal bandwidth & what the circuitry can handle.

 

[Exophase]

If you're asking if it can do multiple resolutions natively then the answer is no, but nothing that I know of really can, much less any LCD. Even CRTs are composed of a fixed (yet very high resolution) set of pixels.

I think that B&W CRTs can have an arbitrary horizontal resolution (depending on how you measure, even fractional) up to the limit of the signal bandwidth & what the circuitry can handle.


The electron beam is arbitrarily scanned but it's hitting a fixed grid of phosphors. That's what the "dot pitch" of a CRT monitor is, and this applies to all CRTs that I know of.

EDIT: Hm, looks like you're right, the phosphers can be arranged in strips instead (aperture grill) to get the effect you're talking about.

 

[atomicthumbs]

On B&W TVs, there wasn't any aperture grill or shadow mask. It's just a big sheet of phosphors; that's why they aren't permanently affected by magnets like color TVs: there's nothing to magnetize.

 

[vampire8bit]

Just a couple of questions.

1. Could we have an RGB output from Pandora somehow to SCART TV's for TV-Out? as in Europe we have this connection for consoles giving a much better picture quality than composite (I think someone else also asked this?)

2. If arcade games can be run in their native resolutions on Pandora eg. (metal slug at 320x224) using Integer pixel "doubling" as DaveC has mentioned, can they keep at this resolution for TV-Out thus allowing us to play arcade (and other computer/console) games near to or at their authentic/native resolutions on 4:3 TV sets?

 

[Squidge]

I don't think the pandora has enough of the external pins available for rgb, but you can have svideo

 

[Clad]

Would be a shame, RGB only requires one more pin than S-Video

(S-Video use two pins for video information, one carry the color signal, the other the brightness signal. RGB use 3, one for each primary color, hence the name)

I'd like RGB too if possible. But well, SVideo is better than composite anyway, so I suppose I couldn't complain if it ends up with only S-Video. (I have the 3 cables for my gamecube, with composite absolutly awful and dirty, RGB being clear and precise, and S-Video having the drawing precise but the colors quite poor)

 

[Squidge]

Would be a shame, RGB only requires one more pin than S-Video

(S-Video use two pins for video information, one carry the color signal, the other the brightness signal. RGB use 3, one for each primary color, hence the name)

RGB needs 5 most of the time, not 3 (Red, Green, Blue, V-Sync, H Sync) as otherwise the TV doesn't know when to move its paint gun.

 

[sbock]

To be exactly:

Most TVs require Red, Green, Blue, the composite signal (which contains V and H-sync) and ground.

There is a variant called RGsB where the sync is overlied to the Green signal.

H-sync and V-sync separately is seldom used for TVs. It's more used for VGA.

Regards,
Stephan

 

[Magnulus]

Hmmm... Can you get the 800x480 resolution through S-video? I hope so...

 

[cappuchok]

I'd like RGB too if possible. But well, SVideo is better than composite anyway

Not on all TV sets, especially those without S-video connectors (which may or may not support S-video over SCART). On my Samsung CRT TV, an S-video-over-SCART signal looks totally distorted compared even to a lowly RF signal. Composite looks somewhat better than RF, but not much. RGB ftw!

 

[WarmFluffyUK]

Not sure if anyone is interested but here's a quick list of input types to a TV/Monitor/Screen in order of quality (Not including HD):

RGB - Best quality, it's almost like you're driving the RGB to the screen directly, this has separate Red, Green, Blue and Composite sync signals. It's good because there's hardly any conversion going on and the red green and blue components are very clean.

Component - This is almost as good as RGB but it combines colour, luma and sync with only 3 signals.

S-Video - This is basically a step up from your basic composite, video (including Sync) and colour are separated into two signals.

Composite video - All Video information and sync are encoded into a single signal.

UHF - The worst of the Worst, this is basically a composite signal converted to UHF carrier for analog broadcast.

Each of the above stages introduces noise into the image, UHF obviously being the worst as you have to take RGB, convert it to composite, then piggy back that onto a UHF carrier wave. This signal is bad enough, but at the other end you do the reverse which introduces even more noise into the signal. Avoid at all costs!

 

[Squidge]

Yes, I forgot sync is multiplexed on TV's.

I still don't think it's going to happen though, considering we will need an extra connector for it. We'd have to remove the current A/V socket, and place a seperate headphone + 8-way A/V socket capable of composite/s-video/rgb, and then people would probably complain saying you only need an extra pin to be vga compatible, then it would grow to 10 pins as a vga monitor can't accept a multiplexed signal last time I checked.

Much better to just leave it as it is, the line has to be drawn somewhere otherwise the cases will never be done!

 

[PokeParadox]

Component - This is almost as good as RGB but it combines colour, luma and sync with only 3 signals.

Only one thing you didn't mention. Component allows progressive scan. RGB is still interlaced, unfortunately...

Oh yes... it would be nice if, on emulators with plenty of CPU cycles left, HQ2X scaling could be an option. It keeps things nice and sharp whilst scaling them upwards.
Hell it could even use the GPU if it were written on the fragment/vertex shaders