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 Post subject: Re: 240p test suite
PostPosted: Wed Jan 31, 2018 11:29 am 
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Shade $0D is unfortunately significantly darker than 0 IRE. The NES was designed for NTSC-J , so there was no design for different black and blanking levels.

This wiki page contains the measurements I did some years ago: color $0D is approximately -12IRE.

With full color emphasis on, shades $01-$0C average to approximately 4 IRE.


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 1:25 pm 
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Even with -12 IRE, I'd still rather have that (and a light grey on the right bar) for some limited functionality, rather than zero functionally with everything the exact same color.

Also the grid on the linearity screen (pressing A) is BY FAR the best and most useful test pattern, (I believe it's 7x7 black pixel squares with 1 pixel thick lines, which are very good parameters) could be EVEN BETTER if pressing A again could cycle to remove the 5 circles, as these circles often get in the way, much like an OSM does when trying to scrutinize a white line for calibration.


Last edited by SpiderWaffle on Thu Feb 01, 2018 4:14 pm, edited 1 time in total.

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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 2:04 pm 
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Location: DIGDUG
You'd rather have this?

https://youtu.be/3fhyX3HdVcg

(the immortal uses color $0d for black here...)

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nesdoug.com -- blog/tutorial on programming for the NES


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 4:20 pm 
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"The game uses a non-standard "blacker than black" color value for black pixels and then further exacerbates the problem by using "emphasis bits" to darken the whole screen. This pushes things even further out of spec so that the TV sees a sync pulse where there shouldn't be one."

Well if that's the case no, but I assume that was with composite, and maybe RF only. I'd be interested in using it for RGBS which would have the sync line separated and couldn't happen. Further, I wonder how much the emphasis bits play a part in that vs -12 IRE instead of the 0 which every CRT is more than designed to handle.

Regardless, a light grey on the right bar would be better.


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 4:52 pm 
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If you're using RGBS from a NESRGB, HDNES, or 2C03, it's already completely synthetic and only vaguely related to the composite generated by the 2C02... I doubt any of those devices emit something useful for shade $0D.

The "SMTPE color bars" test does and "IRE" test can already display shade $0D.


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 8:36 pm 
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"The "SMTPE color bars" test does and "IRE" test can already display shade $0D"

Are you saying they use $0D currently? O.o


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 9:01 pm 
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That is, in fact, exactly what I am saying.
Attachment:
240pee-NES-SMTPE-color-bars-with-shade-0D-indicated.png
240pee-NES-SMTPE-color-bars-with-shade-0D-indicated.png [ 304 Bytes | Viewed 2602 times ]


Attachments:
240pee-NES-IRE-test-with-shade-0D-indicated.png
240pee-NES-IRE-test-with-shade-0D-indicated.png [ 196 Bytes | Viewed 2602 times ]
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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 01, 2018 11:53 pm 
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Location: Canada
From what I recall, the small deep-black region in this ROM's test is not nearly as problematic as with The Immortal. Sometimes how much of it there is onscreen can matter a lot. E.g. my capture card wobbles with The Immortal but didn't seem to be bothered with this test. Loss of picture is theoretically possible, but it really varies from hardware to hardware quite a bit.

Incidentally, this has actually been discussed twice in this thread previously:
https://forums.nesdev.com/viewtopic.php?p=159374#p159374
https://forums.nesdev.com/viewtopic.php?p=178503#p178503


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 08, 2018 12:44 am 
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lidnariq, that's neat they're in there, (though the IRE pattern is somewhat dubious because also has much lower values); unfortunately, it doesn't seem to work at all like others have said, at least with RGBS and S-video through the RGBNES, could it maybe somewhat work through composite/RF unmodded?

I think a better idea, that could still include the marginal useful if any -12 IRE $0D, would be to use all of the NES darkest colors alternating with a black bar, so a pluge pattern like this:

| $0D | $0E | $08 | $0E | $09 | $0E | $00 |

which could be actually pretty useful, I know when turning down the brightness a bit too low you can't distinguish a black from that dark brown, like at the start of Castlevania 3 (dark brown hair on black background and later in level the whole big house background)


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 08, 2018 12:58 am 
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Sorry for double post but this maybe got missed:

The grid on the linearity screen (pressing A again) is BY FAR the best and most useful test pattern. (I believe it's 7x7 black pixel squares with 1 pixel thick lines, which are very good, if not ideal parameters) It could be EVEN BETTER if pressing A again could cycle to remove the 5 circles, as these circles often get in the way, much like an OSM does when trying to scrutinize a white line for calibration, particularly convergence.
(If you wanted to get really fancy, a way to change between just horizontal lines or just vertical lines could be just slightly helpful)

The solid color screen is also awesome for checking purity.
Those two are about the only patterns I use 240p test suite for.
And I guess with higher end consoles, the SMTPE pattern can actually be accurate enough auto-calibrate BVMs and the like.

The sound check, system clock checks, lag test and some others are pretty neat too.

The "Grid" is so over used, the linearity's grid is so much better, grrr.


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 Post subject: Re: 240p test suite
PostPosted: Thu Feb 08, 2018 7:05 am 
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Location: NE Indiana, USA (NTSC)
Thank you for the feature requests.

SpiderWaffle wrote:
I think a better idea, that could still include the marginal useful if any -12 IRE $0D, would be to use all of the NES darkest colors alternating with a black bar, so a pluge pattern like this:

| $0D | $0E | $08 | $0E | $09 | $0E | $00 |

So something like this I take it, where hot pink represents the $0D.
Attachment:
dark_color_bars_proposal.png
dark_color_bars_proposal.png [ 1.62 KiB | Viewed 2443 times ]

How would that test be translated for the RGB consoles (TG16, Genesis, and Super NES)? Mostly I try to track the functionality of the Super NES test, and I might include a corresponding screen in the NES version. I'll pass on your request to the topic on Shmups Forum to see if they can come up with a corresponding test.

SpiderWaffle wrote:
[The Linearity test] could be EVEN BETTER if pressing A again could cycle to remove the 5 circles, as these circles often get in the way, much like an OSM does when trying to scrutinize a white line for calibration, particularly convergence.

The grid in Linearity is 7 pixels wide and 8 pixels tall on NTSC or 8 pixels wide and 11 pixels tall on PAL. This gives it as close as I can get to a square aspect ratio for the grid squares. But loading two images (circles only and circles with grid) takes up all of video memory on the board I'm using. In order to cycle among more than two screens (circles only, circles with grid, grid only, horizontal lines with same spacing as Linearity grid, and vertical lines with same spacing as Linearity grid), I'd need to load screens into video memory in response to a button press. I could do this one of two ways:

  1. Cut to a black screen
  2. Fit the updates into vertical blanking time, which incurs a lag of 40 frames (two-thirds of a second) to load the 5K of data that make up a screen at 128 bytes per frame

As I get time, I'll let Shmups Forum know about the limits of Grid and Linearity when setting convergence to see if there's demand for a fine grid test as you describe.


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 Post subject: Re: 240p test suite
PostPosted: Tue Feb 20, 2018 2:57 pm 
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"So something like this I take it, where hot pink represents the $0D."

Yes, that pattern for the NES would be nice! Since it doesn't have very much in terms of greys, really dark greys, the darkest other colors work better, like the dark brown. Further, half being on white background with lightest colors (maybe the light grey here is good) could be good too, see example link below. *NOTE the continuous gradient stuff in the middle not necessary or especially helpful or applicable for limited color palettes.

"How would that test be translated for the RGB consoles (TG16, Genesis, and Super NES)?"

A pattern like this below is kind of ideal, color/shade labels if not the way can help too, those consoles might have SOME good greys that are actually close to black or close to white, those greys would be good to have, blacker than black, but then the very lightest and very darkest colors also could good to mix in there:
http://spearsandmunsil.com/wp-content/uploads/2013/02/1920x1080p24_Contrast_Main.png

Another good example of effective pluge pattern:
Image


Last edited by SpiderWaffle on Wed Feb 21, 2018 3:15 pm, edited 2 times in total.

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 Post subject: Re: 240p test suite
PostPosted: Tue Feb 20, 2018 3:13 pm 
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"As I get time, I'll let Shmups Forum know about the limits of Grid and Linearity when setting convergence to see if there's demand for a fine grid test as you describe."

The main thing is really just getting that same fine grid patterns, but with the circles removed.

For more capable consoles, getting the white lines as thin as possible is always helpful.
The Parameters are great, 29-30 squares high.


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 Post subject: Re: 240p test suite
PostPosted: Tue Feb 20, 2018 9:01 pm 
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Location: NE Indiana, USA (NTSC)
Would you be happy with a black screen transition between the circles-and-grid screen and the grid-only screen? Or do you require the ability to enable and disable the circles instantly the way the current ROM enables and disables the grid instantly?


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 Post subject: Re: 240p test suite
PostPosted: Tue Feb 20, 2018 11:27 pm 
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"a black screen transition"
You mean like a few frames of black before the just the fine grid comes up?

that wouldn't really be a problem, faster is always better, but a few frames isn't much.

One thing that's nice to switch between quickly is the solid color screens, (mostly just all white and all red) and the fine grid. When doing geometry/convergence adjustments(with fine grid since it's best) some can effect purity (which is best to check with all white and all red) and purity adjustments can effect geometry and convergence. So often I find myself checking fine grid, then B, down, down, A to check purity, then B, up, up A, A back to fine grid, make minor adjustment, repeat.


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