PAL chroma merging?

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thefox
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Re: PAL chroma merging?

Post by thefox »

lidnariq wrote:Eugene, any chance you could take a picture of thefox's or my chroma merging tests? I'm curious whether the Dendy PPU's as peculiar as the 2C07.
A word of caution about my test: it looks like I made it use MMC1 for some reason that I can't remember, but omitted doing any mapper initialization (wtf?). It was probably an accident, so I've attached the same ROM as NROM into the original post.
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Eugene.S
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Re: PAL chroma merging?

Post by Eugene.S »

Uh, Sunrise is coming, so too much glare on TV-screen
Attachments
palblend.jpg
pal-chroma-merge-test.jpg
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thefox
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Re: PAL chroma merging?

Post by thefox »

Eugene.S wrote:Uh, Sunrise is coming, so too much glare on TV-screen
Interesting, looks like Dendy PPU's color generation is indeed different than in 2C07.

Are the colors on the bottom left and bottom right the same?
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Eugene.S
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Re: PAL chroma merging?

Post by Eugene.S »

Do you mean palblend test?
Bottom-right is more violet than bottom-left.
Attachments
kinopio_nes_palette_viewer_updated.nes
(24.02 KiB) Downloaded 379 times
nes palette viewer.nes
(24.02 KiB) Downloaded 374 times
Last edited by Eugene.S on Sat Dec 22, 2018 3:03 pm, edited 2 times in total.
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Re: PAL chroma merging?

Post by Eugene.S »

Here is new, more accurate capturing via AverMedia tuner (thanks to HardWareMan):

Blarrg's Full Palette viewer:
composite: http hwm.us.to/famimusic/Capture/6538_Tests/
Blargg_test_Composite.png
s-video: http hwm.us.to/famimusic/Capture/6538_Tests/
Blargg_test_Svideo.png
Kinopio's test:
composite: http hwm.us.to/famimusic/Capture/6538_Tests/
Kinopio_test_Composite.png
s-video: http hwm.us.to/famimusic/Capture/6538_Tests/
Kinopio_test_Svideo.png
Merge test:
composite: http hwm.us.to/famimusic/Capture/6538_Tests/
Merge_test_Composite.png
svideo: http hwm.us.to/famimusic/Capture/6538_Tests/
Merge_test_Svideo.png
Palblend test:
composite: http hwm.us.to/famimusic/Capture/6538_Tests/
Palblend_test_Composite.PNG
s-video: http hwm.us.to/famimusic/Capture/6538_Tests/
Palblend_test_SVideo.PNG
[moderator: recovered images from web.archive and attached]
Last edited by Eugene.S on Sat Dec 22, 2018 3:06 pm, edited 1 time in total.
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thefox
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Re: PAL chroma merging?

Post by thefox »

Eugene.S wrote:Here is new, more accurate capturing via AverMedia tuner (thanks to HardWareMan):
Are these shots from a different version of the Dendy PPU than the ones from before? In this case the color generation seems to be the same as in 2C07.
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Re: PAL chroma merging?

Post by Eugene.S »

Yes, this is different PPUs

My PPU is:
UMC UA6538
9051-bs
813410
download/file.php?id=1949&mode=view

HWM's PPU:
UMC UA6538
9051-bs
611510
download/file.php?id=24273&mode=view
[moderator: updated URL to forum copies of images]

This is so strange. There are similar chips.
Last edited by Eugene.S on Sat Dec 22, 2018 3:07 pm, edited 1 time in total.
tepples
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Re: PAL chroma merging?

Post by tepples »

Unless different TVs are decoding the signal differently. Could you try the two revisions on the same brand of TV or tuner card?
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Eugene.S
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Re: PAL chroma merging?

Post by Eugene.S »

Yes you are right Tepples.
I've just
replaced
replaced
my PPU to
611510
611510
revision, like HardWareMan have.
And my TV shows
this picture
this picture
like 813410 revision

[moderator: recovered images from web.archive]
lidnariq
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Re: PAL chroma merging?

Post by lidnariq »

Given the Avermedia pictures, I wonder if plugging a 2C07/Dendy straight into S-video luma would give us enough information to reverse engineer what's going on?

Or maybe there's already enough image in the "Kinopio's test: s-video" picture?

It's a little unfortunate that 13.5 MHz ÷ 4.43MHz is only ≈3. Makes it a little more difficult to determine what's going on solely by inspection instead of rigorous measurement.
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HardWareMan
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Re: PAL chroma merging?

Post by HardWareMan »

I can do more (clickable):
http savepic.ru
5809338.png
http savepic.ru
5815482.png
[moderator: recovered images from web.archive.org]
I can disconnect chroma pin to get pure B&W picture with color subcarrier on it, but I think reducing saturation is more than enough. Anyway, these pictures has no most imported part of puzzle: color burst. Because PAL/NTSC decoders adjust their PLL with color burst and then compare phase shift of subcarrier in scanline. So at this pictures we see only relative phase shift between different colors.
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Re: PAL chroma merging?

Post by tepples »

I'd like to see how all $1x colors mix with a neutral gray $00 on alternating scanlines. Should I write a quick test ROM for this?
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Eugene.S
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Re: PAL chroma merging?

Post by Eugene.S »

Yes, you can write it. I and HardWareMan both have InviteNESes flashcartridges to test it.

here is updated version of Kinopio's palette viewer
It work stable on NTSC/PAL/Dendy timings:
https://forums.nesdev.com/download/file.php?id=14270
Attachments
nes palette captured.zip
(7.33 KiB) Downloaded 377 times
Last edited by Eugene.S on Sat Dec 22, 2018 3:12 pm, edited 6 times in total.
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HardWareMan
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Re: PAL chroma merging?

Post by HardWareMan »

tepples wrote:I'd like to see how all $1x colors mix with a neutral gray $00 on alternating scanlines. Should I write a quick test ROM for this?
Yes, please.
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Re: PAL chroma merging?

Post by tepples »

"Your message contains too few characters."
Attachments
palphase-0.01.zip
PAL phase test (NROM-128 binary and source)
(13.59 KiB) Downloaded 380 times
Theoretical output of the program if an RGB PAL NES existed
Theoretical output of the program if an RGB PAL NES existed
palphase_ideal_output.png (8.53 KiB) Viewed 8971 times
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