256 colors remap

[Retrofan]

So... (people must decide), these are the options by now:

Demolition's one:




Lnx one:



Edit: This was mine from the beginning:



... Time for You to decide; I'm not God here.

[James]

http://aminet.net/gfx/misc/png_neuquant_0.41.lha

[Retrofan]

I'm sorry, but surely you haven't tried yours "for real":

http://img21.imageshack.us/img21/8595/dlr0.png

Edit: And watching them now... Lnx was better on the wall paper, but what about the radiator (if it's right in english)? Mine is much better. ... I want your reviews.

[James]

Originally Posted by Retrofan

I'm sorry, but you've got not surely tried it "for real":

Have you just downloaded the thumbnail?
You have to click on it to get the full 800x600 picture...

Direct download:

http://www..com/download/4r...00x600-nq8.png

[Retrofan]

Yes, sorry;




http://img407.imageshack.us/img407/6246/yzz.png

Time for people to decide. I would look just the radiator and the wall paper, but there are more colors and things there; the Post-It on the monitor, the hour on the clock for example... WHICH ONE WOULD YOU CHOOSE?

[pandy71]

Originally Posted by Retrofan

WHICH ONE WOULD YOU CHOOSE?

Hahaha, none of them - jpg just ruined 256 color pictures - jpg is lossy, png is lossless - second, if you don't care about aspect then almost every picture will be good.

Third - i saw best (for me) results with K-means algorithm + Riemersma Dither.

btw - liquid rescale will not work for this image.

Superb comparison especially for developers: http://bisqwit.iki.fi/story/howto/dither/jy/ - pehaps someone wilt wrote new app to convert video and pictures for Amiga graphics chips, perhaps with PCHG?


I just realized that this is png not jpg - sorry for that - it looks like lossy jpg...

Your system desktop probably using only 12bit colors.
Try this image (LnxConvertor - 256 indexes, but only 12bit colors):



LnxConverter priority is quality, not speed it's Beta version.

(sorry for my bad english )

[demolition]

You really should change your system palette to fit the backdrop. It looks like it is being recolored, ruining the colors.

[pandy71]

Originally Posted by Lanex

LnxConverter priority is quality, not speed it's Beta version.

What kind of error distribution is used in Lnx? From my perspective this is weakest part. Especially that for HAM modes different type of dithering must be used to avoid HAM fringe.
Second question - what algorithm for EHB color palette is used?

Originally Posted by pandy71

What kind of error distribution is used in Lnx? From my perspective this is weakest part. Especially that for HAM modes different type of dithering must be used to avoid HAM fringe.
Second question - what algorithm for EHB color palette is used?

for HAM mode is any dithering unusable. EHB? It is too hard to explain… in english language

[pandy71]

Originally Posted by Lanex

for HAM mode is any dithering unusable.

I disagree - HAM need special pre-analysys (similar to FXAA, MLAA or at least edge detection), color palette should be created in particular way to avoid HAM fringing (thus minimize transistion error), vertical dither have no penalties (normal dither favor horizontal direction), perhaps information about eye sensitivity (particular for green) should be also involved in this.

Originally Posted by Lanex

EHB? It is too hard to explain… in english language

English is also not my native and i make lot of mistakes so don't worry.

[pandy71]

--Retrofan contest--

24 bit source:


12 bit version:


240 colours, k-means, Riemersma error diffusion:


16 colors, scolorq:

[Retrofan]

@pandy71 I was very impressed with your "Riemersma" conversion, but as I said a thing is words and another facts. Also as I said, posting (like all of you are doing) a wallpaper isn't the same that posting the image of WB using it, like I do with your images.

This is riemersma on WinUAE. I just taked your photo from here and used it as background; if you want to send me the file, perhaps I am wrong -it can be, it happened with James' one- (don't know why, please excuse me):



If not (now just my humble opinion) I believe Lnx wins, then (and I hate this) "my" unconverted image, then yours/James, then Demolition's.

Edit: BTW Lnx converter works right with 32 bits -well... how long it takes? 3/4 hour to export the image?-. The problem seems to be only with 64.

Edit: And please -you all reading this- do not try to compare them using a Laptop. Use a large screen. I'm using my FullHD 36" Hdmi Tv.

[demolition]

That is probably because WB is recoloring the new background to your current palette, thus replacing the nice palette that was created for it.

It does indeed look very good and it can look just as good in your WB if a new palette is created taking 16 colors from your current palette for the system and then adding the new 240 colors for the background, combining it into a new 256 color palette. The background image should then also be changed to use this exact new palette, and then when the palette is changed in WB as well, everything matches.

I could probably do it, but don't have the time for it right now (bedtime), so if nobody else did it by then, I'll try tomorrow.

[Retrofan]

Thanks, ang great that you'll try that. If you do, please use the first 16 colors of Rebel's one. But perhaps (not sure, but I think so) it's just the image I've used, and pandy71's looks better.

[NovaCoder]

Here's my attempt.

This is actually the worse kind of picture to use for a classic background picture because it has such a wide range of colors.

piccy

[pandy71]

Originally Posted by NovaCoder

Here's my attempt.

This is actually the worse kind of picture to use for a classic background picture because it has such a wide range of colors.

piccy

jpg will ruin any picture - please use any non lossy format (GIF, PNG, IFF, BMP etc)

[Retrofan]

Perhaps it's just that, as it doesn't look right here. http://img824.imageshack.us/img824/7376/u3bm.png

[AnimaInCorpore]

What about this one? 240 colors:



Cheers
Sascha

[pandy71]

Originally Posted by AnimaInCorpore

What about this one? 240 colors:

I miss better error distribution on lamp, also joystick grip (red ball) suffer same problem - (visible heavy banding) - besides this OK for me.