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PAL chroma merging?
http://forums.nesdev.com/viewtopic.php?f=21&t=11018
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Author:  thefox [ Fri Sep 05, 2014 8:48 pm ]
Post subject:  Re: PAL chroma merging?

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.

Author:  Eugene.S [ Fri Sep 05, 2014 9:00 pm ]
Post subject:  Re: PAL chroma merging?

Uh, Sunrise is coming, so too much glare on TV-screen

Attachments:
palblend.jpg
palblend.jpg [ 693.64 KiB | Viewed 2017 times ]
pal-chroma-merge-test.jpg
pal-chroma-merge-test.jpg [ 987.64 KiB | Viewed 2017 times ]

Author:  thefox [ Fri Sep 05, 2014 9:11 pm ]
Post subject:  Re: PAL chroma merging?

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?

Author:  Eugene.S [ Fri Sep 05, 2014 9:18 pm ]
Post subject:  Re: PAL chroma merging?

Do you mean palblend test?
Bottom-right is more violet than bottom-left.

Attachments:
nes palette viewer.nes [24.02 KiB]
Downloaded 86 times

Author:  Eugene.S [ Sat Sep 06, 2014 3:56 am ]
Post subject:  Re: PAL chroma merging?

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

Blarrg's Full Palette viewer:
composite: http://hwm.us.to/famimusic/Upload/Dendy ... posite.png
s-video: http://hwm.us.to/famimusic/Upload/Dendy ... Svideo.png

Kinopio's test:
composite: http://hwm.us.to/famimusic/Upload/Dendy ... posite.png
s-video: http://hwm.us.to/famimusic/Upload/Dendy ... Svideo.png

Merge test:
composite: http://hwm.us.to/famimusic/Upload/Dendy ... posite.png
svideo: http://hwm.us.to/famimusic/Upload/Dendy ... Svideo.png

Palblend test:
composite: http://hwm.us.to/famimusic/Upload/Dendy ... posite.PNG
s-video: http://hwm.us.to/famimusic/Upload/Dendy ... SVideo.PNG

Author:  thefox [ Sat Sep 06, 2014 4:15 am ]
Post subject:  Re: PAL chroma merging?

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.

Author:  Eugene.S [ Sat Sep 06, 2014 4:18 am ]
Post subject:  Re: PAL chroma merging?

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
http://hwm.us.to/famimusic/Upload/Dendy ... posite.png

This is so strange. There are similar chips.

Author:  tepples [ Sat Sep 06, 2014 6:01 am ]
Post subject:  Re: PAL chroma merging?

Unless different TVs are decoding the signal differently. Could you try the two revisions on the same brand of TV or tuner card?

Author:  Eugene.S [ Sat Sep 06, 2014 7:05 am ]
Post subject:  Re: PAL chroma merging?

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

Author:  lidnariq [ Sun Sep 07, 2014 12:22 am ]
Post subject:  Re: PAL chroma merging?

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.

Author:  HardWareMan [ Sun Sep 07, 2014 1:37 am ]
Post subject:  Re: PAL chroma merging?

I can do more (clickable):
Image
Image
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.

Author:  tepples [ Sun Sep 07, 2014 5:59 am ]
Post subject:  Re: PAL chroma merging?

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?

Author:  Eugene.S [ Sun Sep 07, 2014 6:59 am ]
Post subject:  Re: PAL chroma merging?

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

P.S:
Unfortunately kinopio's test works very unstable on Dendy timings and often look like this:
http://savepic.su/4311124.htm
We don't have the source code of "nes palette viewer". Kinopio is offline since june 2014.

Attachments:
nes palette captured.zip [7.33 KiB]
Downloaded 82 times

Author:  HardWareMan [ Sun Sep 07, 2014 6:59 am ]
Post subject:  Re: PAL chroma merging?

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.

Author:  tepples [ Sun Sep 07, 2014 9:28 am ]
Post subject:  Re: PAL chroma merging?

"Your message contains too few characters."

Attachments:
File comment: PAL phase test (NROM-128 binary and source)
palphase-0.01.zip [13.59 KiB]
Downloaded 91 times
File comment: Theoretical output of the program if an RGB PAL NES existed
palphase_ideal_output.png
palphase_ideal_output.png [ 8.53 KiB | Viewed 1907 times ]

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