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PostPosted: Sun Sep 20, 2015 2:30 am 
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DRW wrote: Why?

Because we're all nerds, apparently, and appreciate the experiment Firebrandx is doing.

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PostPosted: Sun Sep 20, 2015 5:36 am 
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rainwarrior wrote:
This is all good information; just because there isnt "one true palette" doesn't mean we can't measure and make use of the characteristics of real world palettes.

Sure, but in this case, you would need to calculate the average of a whole bunch of TVs.

So, if your experiment consisted of getting 100 TVs from different times, brands and models, setting them all to standardized color values, measuring the NES palette and then calculating the average value for each color, then I would say this makes sense.

But if it's just hooking up a screen capture device to a TV and then somehow trying to get the most accurate value in RGB form, this is really a vain attempt. Because you would get totally different results if you used another TV, even if everything else is the same. You cannot get an "accurate" palette if you just use one TV. Because not even this TV is identical to the one of the same brand that was produced next to it in the factory.

Unlike the NES itself, TVs vary greatly among each other. So, the only way to get an accurate palette is to do the described procedure on a whole bunch of TVs and calculate the average value.

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PostPosted: Sun Sep 20, 2015 5:56 am 
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I'm a little skeptical about the existence of an ideal NES RGB palette myself, but I appreciate the effort in the attempt to find it. Having a few real world examples is nice, even if they don't match everyone's personal experiences.


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PostPosted: Sun Sep 20, 2015 6:14 am 
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It makes me wonder whether there's even an ideal palette for RGB systems such as the Genesis and Super NES, given the differences between the RGB values and the result after they've been encoded to composite by the console and decoded back to RGB by the TV.


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PostPosted: Sun Sep 20, 2015 11:30 am 
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Yeah, I wonder about that too. But since those systems have RGB palettes to begin with, people don't usually care much, and just assume the colors reach the TV intact. Some emulators don't even map the range to 0..255 properly, and just shift the smaller ranges left, leaving the list bits clear.


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PostPosted: Sun Sep 20, 2015 12:24 pm 
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DRW wrote:
Because you would get totally different results if you used another TV, even if everything else is the same.

It's not totally different from TV to TV, it's subtly different. This is a very important distinction! Most will be relatively close to the average, and even one point of data on it is immensely better than no points of data.


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PostPosted: Sun Sep 20, 2015 12:29 pm 
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tokumaru wrote:
But since those systems have RGB palettes to begin with, people don't usually care much, and just assume the colors reach the TV intact.

If we can assume as an axiom that Super NES "colors reach the TV intact", then the proper approach to derive an NES palette is to find, for each NES color, the Super NES color that produces a composite waveform with the same amplitude and phase.


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PostPosted: Sun Sep 20, 2015 7:52 pm 
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tepples wrote:
a composite waveform with the same amplitude and phase.
If my understanding of the NTSC signal is correct, I think you'd want to match the amplitude, phase, and "center height" as in this diagram. (I'm not sure what the best term for "center height" is.)


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PostPosted: Sun Sep 20, 2015 8:01 pm 
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"center height" = "luma"

Ok, fine, "mean" or "average".


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PostPosted: Tue Sep 22, 2015 2:15 am 
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tokumaru wrote:
Firebrandx wrote:
it looks like I'd need to also get their composite converter cable as their devices don't readily accept composite input.

Doesn't adding more conversion steps to the process increase the chances of the colors being modified along the way?



I worry about this too, which is why I looked at many different devices on the market. I tried the Hauppauge PVR 2 with the composite video cable you can order for it, but the picture came out scrambled like it couldn't handle 240p or something. That was very disappointing, because it would have been a direct link from the console to the device without the need of a converter.

I think I should at least give the Avermedia coverter + capture method a try though.


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PostPosted: Wed Sep 23, 2015 1:03 pm 
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The most important thing about NES palettes is the fact that several colors are out of gamut, meaning they feature R, G, or B values that are below 0 or above 255. Below 0 is usually clipped to 0, but above 255 has no "right" way of fixing. It's mostly the blues that are out of gamut, but some purples and at least one red is too. An average, run-of-the-mill NES palette will just clip those colors, which alters either the hue, the saturation, the luminance, or any combination of those three things.

The only "accurate" way to portray those colors is to darken the whole palette until those colors enter the gamut. That, above all else, will give you the most meaningfully "accurate" palette, but I'd only use one of those if I were designing graphics for an actual NES console. For just playing games, it's usually fine to have a palette with a couple of clipped colors, just as long as the hues of most other colors looks right to you, and because which hues look "right" depends on the person, having a palette generator with a hue knob helps.


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PostPosted: Wed Sep 23, 2015 1:22 pm 
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It would appear that there are as many "accurate" NES palettes as there are people with capture devices. Meanwhile, both developers and players back in the day would just tweak their TV sets to make them look "nice". At least most of these "accurate" NES palettes still look halfway decent, unlike that desaturated slop from those "accurate" Commodore 64 palettes.


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PostPosted: Thu Sep 24, 2015 9:45 am 
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Why not hook it up to a scope and analyze it that way? As in, remove as many variables as possible. Capture cards are nice, but I wouldn't rely on them to be extremely accurate; there purpose isn't accuracy relative to game console video output.

NewRisingSun wrote:
It would appear that there are as many "accurate" NES palettes as there are people with capture devices. Meanwhile, both developers and players back in the day would just tweak their TV sets to make them look "nice". At least most of these "accurate" NES palettes still look halfway decent, unlike that desaturated slop from those "accurate" Commodore 64 palettes.

^This.

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PostPosted: Thu Sep 24, 2015 10:33 am 
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tomaitheous wrote:
Why not hook it up to a scope and analyze it that way? As in, remove as many variables as possible. Capture cards are nice, but I wouldn't rely on them to be extremely accurate; there purpose isn't accuracy relative to game console video output.
HardWareMan got it: viewtopic.php?p=112191#p112191

Fact of the matter is, we already know exactly how the digital portion works, and the outside-the-IC part is so simple there's nothing variable there. And all of this is accurately simulated by Bisqwit's and Drag's palette generators.

The only possible remaining variation in colors would be if the output impedance from the NES varies significantly across the 10 different voltages the PPU can emit. And even then, that should really just come down to a little variation in net hue rotation, net brightness, or net saturation.


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PostPosted: Thu Sep 24, 2015 11:19 am 
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NewRisingSun wrote:
At least most of these "accurate" NES palettes still look halfway decent, unlike that desaturated slop from those "accurate" Commodore 64 palettes.


That's because the video generator circuitry inside the C64's VIC-II chip has been accurately modelled. If the resulting colours are unsatisfactory then one should adjust the brightness/contrast/hue settings in the emulator's CRT emulation settings... just like an actual CRT.

Oh, and lets not forget the whole PAL/NTSC thing.

Custom RGB palettes for machines whose chipsets natively generate composite/Chroma+Luma signals should be consigned to the past.

lidnariq wrote:
Fact of the matter is, we already know exactly how the digital portion works, and the outside-the-IC part is so simple there's nothing variable there. And all of this is accurately simulated by Bisqwit's and Drag's palette generators.

What more beyond this is needed? (Beyond brightness/contrast/hue controls)

Anything else is at risk of being contaminated by differences in colour decoding hardware and rose-tinted filters. :mrgreen:

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