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Forums > CSDb Discussions > colodore is the new pepto
2016-12-12 00:26
pepto
Account closed

Registered: Nov 2004
Posts: 35
colodore is the new pepto

Hey guys, I remeasured the video-signals of my VIC-II's and slightly updated my 15 year old attempt at calculating an rgb-clone. While at it, I also measured VIC & TED and made a little website about it, that allows you to adjust brightness, contrast and saturation as you like and then save your own custom palette to a png-file.

http://www.colodore.com


I took extra care to make sure, that the brightness, contrast and saturation sliders behave the same way as my 1084s.

While closely comparing my LCD to the 1084s, I found that making the transparency of scanlines dependent on YUV's Y (so they are less visible for brighter colors) looked a lot more like the real thing. I also noticed that the phase-shift on odd-lines happens for YUV's V only and there's even a name for it in video-lingua: hanover bars.

After implementing this, I'm happy to say that the images on my LCD and 1084s are remarkably close.


I will write a more detailed article about it in January, but seriously need a christmas-break first...

Cheers,
pepto
 
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2016-12-13 21:42
Mr. SID

Registered: Jan 2003
Posts: 419
With the default settings, it seems like the white on the webpage is actually #ffffff, but when I save the PNG, white is #fefefe. Any idea why? Screwed by color space, or just a rounding error?
Also, saving to ACT doesn't actually work for me, nothing happens when I click it (Safari, macOS Sierra).
2016-12-13 21:54
pepto
Account closed

Registered: Nov 2004
Posts: 35
Quote: With the default settings, it seems like the white on the webpage is actually #ffffff, but when I save the PNG, white is #fefefe. Any idea why? Screwed by color space, or just a rounding error?
Also, saving to ACT doesn't actually work for me, nothing happens when I click it (Safari, macOS Sierra).


Ah, I parseInt() it in the png-writer, maybe I should Math.round() it... i will investigate. I'm running Safari on macOS Mavericks and it works just fine, I'll have to see how I'm able to check what Sierra's problem is. Maybe a suspicious file-suffix? Is there an option to download only "safe" files or something stupid like that? As far as I can see, I'm building it the same way as the png-file -- it doesn't have it's own mime-type like png (image/png) though, it's an "octet-stream"...

Thanks for the feedback!
2016-12-13 22:03
Mr. SID

Registered: Jan 2003
Posts: 419
I have no idea, but it doesn't even try to download. Works fine in e.g. Firefox. FWIW, the .act also has #fefefe for white.
2016-12-13 22:31
pepto
Account closed

Registered: Nov 2004
Posts: 35
Quote: I have no idea, but it doesn't even try to download. Works fine in e.g. Firefox. FWIW, the .act also has #fefefe for white.

...should be #ffffff now...
2016-12-13 22:36
pepto
Account closed

Registered: Nov 2004
Posts: 35
Quote: ...should be #ffffff now...

Don't tell @saimo though, noone will notice anyway... ;)
2016-12-13 22:50
saimo

Registered: Aug 2009
Posts: 36
Quote: Don't tell @saimo though, noone will notice anyway... ;)

Too late.
I feel idiot. No, wait: superidiot. I guess that the palette download option has been up there all the time, right? Guess what? I had not even noticed there was a menu. So I had grabbed the palette manually. And I did notice that black was #000100 and white was #FCFFFB, but I thought that the measuraments had revealed that the actual output isn't perfectly pure.
OMG, if I think that I have to redo it all again (I had gone as far as redefining the colors also in webpages like https://retream.itch.io/quod-init-exit-iim)... 8o
2016-12-13 23:10
pepto
Account closed

Registered: Nov 2004
Posts: 35
Quote: Too late.
I feel idiot. No, wait: superidiot. I guess that the palette download option has been up there all the time, right? Guess what? I had not even noticed there was a menu. So I had grabbed the palette manually. And I did notice that black was #000100 and white was #FCFFFB, but I thought that the measuraments had revealed that the actual output isn't perfectly pure.
OMG, if I think that I have to redo it all again (I had gone as far as redefining the colors also in webpages like https://retream.itch.io/quod-init-exit-iim)... 8o


Dude, chillax... this whole thing is all about that there is not ONE ULTIMATE rgb-clone of the VIC II palette. The defaults you see when the page is loaded, are what I feel looks like MY Commodore 1084s. If you move one of the sliders for one pixel, you will have several colors go off in all kinds of directions while it is rounded into 8 bit rgb-values again.

colodore is about what YOU feel looks right. Set the sliders so you like the result, that's what ppl with real equipment do and EVERYONE does this differently, as it's a matter of personal taste.


There's no one-fits-all palette and I only have defaults, because you have to start with something. Please don't write the rgb-values somewhere and think "this is colodore". It should be different for everyone else. It's important that the colors are generated on the same underlying logic, so their relation fits.

Besided, the luma-values in the calculation are exactly the same as in my research from 2001. The reason they may appear a bit different now, is that there's a contrast-slider here and I scrolled it a tiny notch to the right for the defaults, as this looks more like on my 1084s. Contrast affects the luma-values of course.

Sorry if this was in any way misleading, maybe you should wait for the tech-doc in January. :-/
2016-12-13 23:18
saimo

Registered: Aug 2009
Posts: 36
Hehe... Sure, pepto ;) It's just that your study defines a (new) virtual standard, and I like the idea of sticking to something that everyone can refer to. Practical case: if I see someone playing the game on an emulator with terribly sick colors (like, red darker than brown), I can provide a respectable reference for him/her to enjoy.
The rest is only my sick perfectionism (which now just pushed me to update again also my FB profile picture) :p
2016-12-14 02:22
chatGPZ

Registered: Dec 2001
Posts: 11088
what he said is THE big problem with "the pepto palette" :) a lot of people dont understand that such thing does not exist, and that you are supposed to adjust it to your liking.

VICE btw uses the luma values from marko makälas measurements, and they will be different depending on what videochip you are emulating - just like different C64s look different too. and if you dont like it - adjust it :)
2016-12-14 07:12
Hein

Registered: Apr 2004
Posts: 933
Thanks, added the default to my PS swatches, let's see how creating mock-ups goes.
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