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Member Since 15 Apr 2006
ONLINE Last Active Today, 2:28 PM

#3897136 Images generated by RastaConverter

Posted by a8isa1 on Today, 10:00 AM

Grew tired waiting for this picture to get better. 


Moving on to the next one(s)...


Attached File  a8isa1_maine_coast.xex   21.98KB   6 downloads

Attached File  a8isa1_maine_coast_PAL.xex   22.05KB   9 downloads


#3895704 Images generated by RastaConverter

Posted by a8isa1 on Wed Nov 22, 2017 8:52 AM

Sure...I'm not sure what the command line is for though, is that for RastaConverter command line? I use the GUI front, so I don't use commands. 


Edit: Looks good on my setup! The colors all look good, bright red car. looks even better in real life than the screen shot here. The greens are more olive colored than in the emulator. There's a bit of red banding in the trees that doesn't show up on your screen shot. Of course I have been playing with my 1200XL's color pot recently and may not have reset it perfectly. 

Ugh! Banding is always a concern but the red at the edge of the shadow of the Chevy is more of an issue.  That's false color.  I didn't see it in the emulator.  Using the regular palettes.


Command was just the invocation of the emulator, Atari800, from which I get screens.  Users need my palette to get the same saturated colors in my image (if not using real hardware).



Give my palette a try for Rastaconverter.  My palette has lowered contrast. I find I always need at least " /contrast=15".  If you use "/S=1" you will get usuable test renderings almost immediately (well, in a couple of minutes).   If you get bright pink pixels where they don't belong then /dither_val is too strong.  If you get charcoal gray pixels prominent in dithers (where gray doesn't belong) try combinations of lower gamma and higher contrast.  This tip seems to work best with 'chess' and 'line' dithers.  Less so with 'jarvis'.  Not at all with 'knoll'

#3895341 Images generated by RastaConverter

Posted by a8isa1 on Tue Nov 21, 2017 7:14 PM

Gunstar, if you don't mind would you please give this PAL picture a try on real hardware?


It's still a WIP but it's close to done (I hope).





Attached File  cuba_56chevy_PAL.xex   22.13KB   18 downloads



Attached File  pal_241_15start_30sat.zip   935bytes   6 downloads


Typical command

atari800 -windowed -pal -palettep pal_241_15start_30sat.pal -run cuba_56chevy_PAL.xex

#3892007 Images generated by RastaConverter

Posted by a8isa1 on Thu Nov 16, 2017 6:18 PM

My reds are as good, but then I have a special video upgrade. Like my 'Chevy V8' pic above, compared to viewing it on my real Atari, that .png image does look drab and almost brownish. My Steam-Punk pictures with all their subdued colors are perfect for stock Atari's.

Unfortunately I don't have any PAL gear. I'll look at your pics again with one of my modified palettes.

#3891830 Images generated by RastaConverter

Posted by a8isa1 on Thu Nov 16, 2017 1:44 PM

a8isa1, That's how I remember my Atari looking on a colour TV, very vivid bright colours, not the washed out colours that emulator palettes show (especially red). If you wanted desaturated colours, you turned the colour knob leftwards!


I dragged out the old "portable TV".   Sure enough it is as colorful (but not the color red) as the screens I posted.

#3890642 Images generated by RastaConverter

Posted by a8isa1 on Tue Nov 14, 2017 9:42 PM

For a split second I thought you were showing screen shots of an Atari with a video upgrade, because that's what Rasta images look like to me on my 1200XL, but then my eyes adjusted to the blinding color, and I noticed the Atari 800 Emulator bit. Very interesting stuff, I'll definitely try your palettes and check out those images .XEX's on my 8-bit and see if I'm blinded by science. ;-)

I have and old TV I can move back to the desk.  It's default setting already has colors that are too saturated.  My eyes might fall to the floor.

#3890618 Images generated by RastaConverter

Posted by a8isa1 on Tue Nov 14, 2017 8:56 PM

Real Colors!


embroidery_screen.png bokeh_screen.png candies_screen.png european-bee-killer-screen.png billiards_screen.png happy_birthday_screen.png paperclips_screen.png nature_screen.png bouquet_screen.png pencils_screen.png salad_screen.png water_screen.png


Here's a screenshot of a conversion session, very early in the process.



OK.  Back to reality.


I did generate the above picture conversions using rastaconverter but I used palettes with vivid colors.   The pictures are displayed using the same palettes.


Here is what some of the pictures look like using the "default" palette for Atari800



paperclips_atari800_default.png nature_atari800_default.png birthday_atari800_default.png


The colors are muted but still completely present.


I stumbled on this technique which yields more saturated colors from rastaconverter by accident.  I was reading Trebor's thread regarding 7800 palettes and learned that palettes were created to make emulators present video like the real machines they emulate.  They are biased.  This made me wonder if we should be using the same biased palettes when converting pictures with rastaconverter.  Shouldn't we use a neutral palette?


I don't have Trebor's expertise and don't have any tools of my own to speak of so I used Altirra and Jakub palette (which looks fairly balanced to my untrained eyes).  I adjusted the start hue going on Analog Pocket Programmer's Guide's description of the hues. Hue 1 Light Orange. Hue 2 Orange. I arrived at Hue Start of -44 degrees.  From there I assumed colors were separated by 22.5 (360 / 16)degrees. Yes, I wondered (and still do wonder if grayscale is a special case that should be discounted but I ignored the idea). Altirra's edit colors menu has a granularity that forced me to select 22.4 degrees.  I made brightness 0.  Contrast is now 80%.  I don't remember my rationale for selecting this.  Pictures seemed to be more agreeable when running rastaconverter so I stuck with that number.  I was getting some nice color but not any completed conversions.   At some other point I decided I wanted the color red to be more vibrant.  I knew this is a weakness in Atari's rendering of color but I tried to make it just a little better.  I boosted Altirra's saturation number to 30.  I exported these changes to a palette file.


Running conversions with the new palette I noticed one thing instantly,  the source and destination pictures in Rastaconverter's progress window now had similar amount of brightness, contrast, and absolutely saturation.  Not long after that I also noticed a recognizable picture was forming within seconds (/s=1 parameter was used).  I also saw more colors and the dither pattern was not prominent.  I some pictures I can't even find the dithering.


I get pictures that are strong facsimilies of the sources in just minutes. (again '/s=1').


Now for the bad news.  The pictures stall very quickly.  In my mind when normal dist is ticking off slowly in the 5th significant digit the picture is "stalled".  They stall with quite noticible errors still in them.


I can't produce what I consider completed conversions using this technique.    I've run some conversions for up to a day.  Most of them don't even reach the quality of the ones above, using /s=1, which were all done in less than 5 minutes.  In fact I set the conversions with /max_evals=41000000, 41 million.


Anyway,  I just wanted to share what I learned.   Below I'm enclosing the two palettes with vivid colors and two ATRs containing my executables of the pictures above.   For the PAL executables I cheated.   All my original conversions were done using the NTSC palette.   For PAL conversions just grabbed the OUTPUT.PNG file, which is already a local solution, and fed that back rastaconverter but using the PAL palette.   In this run I skipped dithers, and image settings.   I assumed rastaconverter would resolve the pictures instantly.   They didn't. However, after just 4.5 million evaluations they compare favorably with the NTSC ones so I'm running with the decision



How I use these palettes in atari800 (linux build)


./atari800 -ntsc -paletten <palette path> -windowed -nosound a8isa1_set3.atr


For Atari800Win Plus I think equivalent parameters are available when the program is evoked from the Windows Command line.


I don't see an option to import palettes in Altirra but the video color adjusting tool will let you make the same changes I described above.


For PAL Everything is the same except Hue Start is -15


For either video standard start with the jakub.pal preset



These pictures work for me on my 800 XL but my CRT (VGA on a scan converter is failing).   I'm curious how (or if) they work on real Ataris for people with better equipment, preferably via a PVM.   I don't want people to mess up their preferences but if these work they would need monitors at their factory defaults (Atari likewise though I don't know how one restore an Atari to the factory setting for the color trim pot)


I don't think these will work well via VBXE which I understand has the laoo palette installed but all feedback is welcome.






Palettes & ATRs

Attached Files

#3884440 I live with idiots

Posted by a8isa1 on Sun Nov 5, 2017 5:58 PM

Some people take flame wars much too far.

#3883545 DIY SIO Hub - Is there anything I'm missing?

Posted by a8isa1 on Sat Nov 4, 2017 12:32 PM

Fair enough.  I'm looking forward to seeing your completed project. 


When you have the extra SIO ports you'll wonder how you ever managed without them.

#3883448 DIY SIO Hub - Is there anything I'm missing?

Posted by a8isa1 on Sat Nov 4, 2017 9:44 AM

I plan to build a 3 connector SIO hub using an old Axiom AT-846 case (and parts).


Is it as simple as just running all pins in parallel or is there more to it?


Seems simple enough and feel it should just be a pass-thru with no extra connectors or parts.

Have you seen Best Electronics' Apelink?  It's available in kit form. 


Take note that some plastic cutting is required if you wish to use the 3rd SIO port and if you wish to have 3 available ports you must supply your own SIO half cable.  Otherwise all the parts required are included in the full kit and yes, just straight thru wiring to each port. Just solder the SIO jacks and the SIO half cable.


I bought 3 of these long ago but have so far only assembled one and not quite for the purpose intended.   I hacked in a barebones (no buttons, no LEDs) SDrive which left room for only two available SIO ports.

#3879101 Images generated by RastaConverter

Posted by a8isa1 on Sun Oct 29, 2017 12:23 PM

You're not done till you've wrapped the evaluation counter around a couple of times 😁
Sometimes it helps going back to an earlier save and continuing. You might luck out on a better solution as it's fairly random, although some solutions are much more probable to be found.

It's still going, now at just over 1 billion evaluations and about 16 hours later.   I'm still not getting the detail I'm looking for.  One error looks like a tractor beam placed on the sting ray.  The other one is the large gray fish (a grouper?) hasn't an eye.  These are the things that most ruin the picture.


The image looks like this in Altirra (custom colors used, custom palette for rastaconverter)



NormDist had dropped by 0.5 to 40.9, not much improvement for 16 more hours of computation

#3878646 Images generated by RastaConverter

Posted by a8isa1 on Sat Oct 28, 2017 7:42 PM

I'm quite annoyed the conversion has stalled at this point




I was so close!

#3875326 Images generated by RastaConverter

Posted by a8isa1 on Tue Oct 24, 2017 10:04 AM

That has to do with the DLI's (Display List Interrupts) that are used, and what is happening is in those dark areas Rastaconverter is using the darkest luminance of a color instead of reverting to black. The only thing I have found to counter this is simply raising the contrast until all those areas become pure black. It really what I think is a problem with the Atari's built-in color palette; the darkest luminance on every color should have been darker or true black, The Atari's palette should have been set to have one lighter, almost white, luminance for each color and one darker, black or virtually black color. It's like the gray scale colors of the Atari are slightly higher contrast (one of 8/16 luminances) than the colors.  

I don't know the structure of a palette file.  Could we just substitute an absolute zero for all hues with 0 value luma in the palette file?


I have tweaked palette that essentially raises the black threshold and lowers the brightness to compensate but I use it only for processing.  The tweak is too exaggerated to use on this picture.

#3875303 Images generated by RastaConverter

Posted by a8isa1 on Tue Oct 24, 2017 9:19 AM

I was adjusting to catch more of the "misty" atmosphere, and that's what I got. I've got one with better color, and it looks a bit misty-er but too much DLI color-banding. I'm not sure if that's what you are referring too, or if the color bands you mean are what I refer to at the line-errors that are caused by Rasta's algorithm stumbling over itself while climbing up hill...

The banding are areas that would normally have dark shadows and forground colors but instead look as if someone painted stain in a complete band, horizontally.


I might have the project still on file...



Looks as though I had restarted the conversion but I can still show the banding.


Here is output.png.  Other than needing more processing it's pretty clean.



This is a screenshot with my palette color changes (i.e. palette used for the conversion).  One band is clear to see. The second one is less visible.



and here is the same screenshot using the default NTSC XL palette.  The banding gets exaggerated thus helps demonstrate what I'm talking about. It looks as if a brush dragged gray stain across the picture.


#3875267 Images generated by RastaConverter

Posted by a8isa1 on Tue Oct 24, 2017 8:15 AM

These are a few that I attempted over and over, and was never satisfied with the results, but these are the best versions, and after time away and a fresh look, I think they are still worth releasing, considering the A8's limitations. They're still brilliant graphic images to see on an Atari.

Great pics


That "emerald forest" pic has been through rastaconverter here about 3 dozen times.  Every time I get close I get bands that ruin the picture.


I still don't know how you manage your balance of colors.