RGB output from composite PPU

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

Moderators: B00daW, Moderators

User avatar
MottZilla
Posts: 2832
Joined: Wed Dec 06, 2006 8:18 pm

Re: RGB output from composite PPU

Post by MottZilla » Tue Oct 29, 2013 10:06 am

mikejmoffitt wrote: Typically I have found most HD CRTs (all maybe?) seem to in practice be like any other digital television, and just happen to have a CRT as the output device rather than an LCD / PDP / whatever, and they won't usually change scan rate for older devices but rather scale up like any modern set.
This is what I assumed. Which if true means they should be avoided just like LCDs and other digital displays for retro use. If you have a digital display you may as well just use an emulator rather than deal with terrible video quality.

User avatar
mikejmoffitt
Posts: 1348
Joined: Sun May 27, 2012 8:43 pm

Re: RGB output from composite PPU

Post by mikejmoffitt » Tue Oct 29, 2013 4:00 pm

MottZilla wrote:
mikejmoffitt wrote: Typically I have found most HD CRTs (all maybe?) seem to in practice be like any other digital television, and just happen to have a CRT as the output device rather than an LCD / PDP / whatever, and they won't usually change scan rate for older devices but rather scale up like any modern set.
This is what I assumed. Which if true means they should be avoided just like LCDs and other digital displays for retro use. If you have a digital display you may as well just use an emulator rather than deal with terrible video quality.
Exactly.

User avatar
mikejmoffitt
Posts: 1348
Joined: Sun May 27, 2012 8:43 pm

Re: RGB output from composite PPU

Post by mikejmoffitt » Wed Oct 30, 2013 10:39 am

Has anyone received an NESRGB board yet? I ordered one when it was available and really have no idea what to expect for shipping times.

User avatar
yxkalle
Posts: 61
Joined: Sun Jan 27, 2013 7:30 pm

Re: RGB output from composite PPU

Post by yxkalle » Fri Nov 01, 2013 7:00 am

I just got an e-mail from Tim, telling me that he has posted my two kits. Expected arrival: 1-2 weeks.

Wohoo! :D

User avatar
mikejmoffitt
Posts: 1348
Joined: Sun May 27, 2012 8:43 pm

Re: RGB output from composite PPU

Post by mikejmoffitt » Fri Nov 01, 2013 8:00 am

yxkalle wrote:I just got an e-mail from Tim, telling me that he has posted my two kits. Expected arrival: 1-2 weeks.

Wohoo! :D
I just did as well. I am excited!

User avatar
yxkalle
Posts: 61
Joined: Sun Jan 27, 2013 7:30 pm

Re: RGB output from composite PPU

Post by yxkalle » Wed Nov 06, 2013 4:28 pm

As the NESRGB board is not really designed to fit inside a Twin Famicom I manufactured this displacement cable to move the PPU a bit. I used an old IDE cable and two IDC-DIP flat cable connectors. I have yet to receive my boards but it seems to work fine with just the PPU in place (maybe a tad bit more jailbars).
20131106_235951.jpg
Isn't it a thing of beauty? ;)
20131107_000333.jpg
EDIT:
I had to shorten this cable quite a bit, for various reasons. New pictures when I receive my NESRGB boards. ;)

User avatar
Drakon
Posts: 183
Joined: Mon Aug 16, 2010 4:48 am
Contact:

Re: RGB output from composite PPU

Post by Drakon » Thu Nov 07, 2013 9:39 pm

Some av famicom pics:

Image

Image

Image

Image

Image

The audio circuit got changed around a little, adjusted the gain and filtering so it can be fed straight into famicom pin 45.

hyarion
Posts: 164
Joined: Tue May 05, 2009 6:12 pm
Contact:

Re: RGB output from composite PPU

Post by hyarion » Thu Nov 07, 2013 11:12 pm

Nice Drakon! But why do you use hot glue on that cable (by the contact)? Wouldn't it be better to use heat shrink tubing instead?
You can buy it dirty cheap at: http://dx.com/p/1m-black-heat-shrink-tu ... -5mm-23450

3gengames
Formerly 65024U
Posts: 2269
Joined: Sat Mar 27, 2010 12:57 pm

Re: RGB output from composite PPU

Post by 3gengames » Thu Nov 07, 2013 11:46 pm

He glues everything, don't even say anything, that's very conservative from his norm. :P

User avatar
yxkalle
Posts: 61
Joined: Sun Jan 27, 2013 7:30 pm

Re: RGB output from composite PPU

Post by yxkalle » Thu Nov 07, 2013 11:56 pm

I just inspected how Nintendulator generates it's RGB palette (this is the one used in NESRGB when you choose the "composite" palette) and it worries me a bit that many colors fall outside of the RGB matrix (i.e. clipping).

Here's the list, clipped values in red:
  • 00 = RGB(102, 102, 102)
    01 = RGB(-24, 43, 155)
    02 = RGB(17, 15, 193)
    03 = RGB(64, -8, 188)
    04 = RGB(103, -19, 143)
    05 = RGB(124, -15, 69)
    06 = RGB(121, 2, -14)
    07 = RGB(96, 28, -83)
    08 = RGB(55, 57, -121)
    09 = RGB(8, 80, -117)
    0A = RGB(-31, 91, -71)
    0B = RGB(-52, 87, 3)
    0C = RGB(-50, 70, 85)
    0D = RGB(-30, -30, -30)
    0E = RGB(0, 0, 0)
    0F = RGB(0, 0, 0)
    10 = RGB(174, 174, 174)
    11 = RGB(7, 97, 245)
    12 = RGB(62, 59, 295)
    13 = RGB(124, 29, 290)
    14 = RGB(176, 14, 230)
    15 = RGB(204, 19, 131)
    16 = RGB(201, 42, 21)
    17 = RGB(167, 77, -71)
    18 = RGB(112, 115, -121)
    19 = RGB(50, 145, -115)
    1A = RGB(-2, 160, -55)
    1B = RGB(-30, 155, 43)
    1C = RGB(-26, 132, 153)
    1D = RGB(0, 0, 0)
    1E = RGB(0, 0, 0)
    1F = RGB(0, 0, 0)
    20 = RGB(256, 256, 256)
    21 = RGB(86, 178, 328)
    22 = RGB(142, 139, 379)
    23 = RGB(205, 108, 373)
    24 = RGB(258, 93, 312)
    25 = RGB(286, 98, 212)
    26 = RGB(283, 122, 101)
    27 = RGB(249, 157, 7)
    28 = RGB(193, 196, -44)
    29 = RGB(130, 226, -38)
    2A = RGB(77, 241, 23)
    2B = RGB(49, 237, 122)
    2C = RGB(52, 213, 234)
    2D = RGB(79, 79, 79)
    2E = RGB(0, 0, 0)
    2F = RGB(0, 0, 0)
    30 = RGB(256, 256, 256)
    31 = RGB(186, 224, 286)
    32 = RGB(209, 208, 307)
    33 = RGB(235, 195, 304)
    34 = RGB(257, 189, 279)
    35 = RGB(268, 191, 238)
    36 = RGB(267, 201, 192)
    37 = RGB(253, 215, 154)
    38 = RGB(230, 231, 133)
    39 = RGB(204, 244, 135)
    3A = RGB(183, 250, 160)
    3B = RGB(171, 248, 201)
    3C = RGB(172, 238, 247)
    3D = RGB(183, 183, 183)
    3E = RGB(0, 0, 0)
    3F = RGB(0, 0, 0)
And now when I think of it, isn't black supposed to be at RGB(16, 16, 16) and white at RGB(235, 235, 235) on a TV?

Skips
Posts: 1
Joined: Sat Nov 09, 2013 5:52 pm

Re: RGB output from composite PPU

Post by Skips » Sat Nov 09, 2013 6:05 pm

hyarion wrote:Nice Drakon! But why do you use hot glue on that cable (by the contact)? Wouldn't it be better to use heat shrink tubing instead?
You can buy it dirty cheap at: http://dx.com/p/1m-black-heat-shrink-tu ... -5mm-23450

Because why buy this

Image

and do it right...

When you can buy this and add some "flare" to your work!

Image

User avatar
mikejmoffitt
Posts: 1348
Joined: Sun May 27, 2012 8:43 pm

Re: RGB output from composite PPU

Post by mikejmoffitt » Thu Nov 14, 2013 11:25 am

yxkalle wrote: And now when I think of it, isn't black supposed to be at RGB(16, 16, 16) and white at RGB(235, 235, 235) on a TV?
I don't see why we wouldn't want to map black to 0,0,0 and white to 255,255,255, though.

User avatar
blargg
Posts: 3715
Joined: Mon Sep 27, 2004 8:33 am
Location: Central Texas, USA
Contact:

Re: RGB output from composite PPU

Post by blargg » Thu Nov 14, 2013 11:32 am

You know, I could have easily gone down the path of using lots of hot melt glue in my electronic projects. That the stuff turns into spider webs and gets caught up in everything is probably the biggest reason I avoid it most of the time. I can't stand those little strings stretching out. I think the high-temperature glue sticks might be better, but it's not common or cheap.

User avatar
mikejmoffitt
Posts: 1348
Joined: Sun May 27, 2012 8:43 pm

Re: RGB output from composite PPU

Post by mikejmoffitt » Fri Nov 15, 2013 10:50 am

blargg wrote:You know, I could have easily gone down the path of using lots of hot melt glue in my electronic projects. That the stuff turns into spider webs and gets caught up in everything is probably the biggest reason I avoid it most of the time. I can't stand those little strings stretching out. I think the high-temperature glue sticks might be better, but it's not common or cheap.
Unfortunately for mounting the NESRGB in an original Famicom using glue is mostly unavoidable. I've gotten pretty good at not making glue webs, though.

User avatar
yxkalle
Posts: 61
Joined: Sun Jan 27, 2013 7:30 pm

Re: RGB output from composite PPU

Post by yxkalle » Fri Nov 15, 2013 2:00 pm

mikejmoffitt wrote:
yxkalle wrote: And now when I think of it, isn't black supposed to be at RGB(16, 16, 16) and white at RGB(235, 235, 235) on a TV?
I don't see why we wouldn't want to map black to 0,0,0 and white to 255,255,255, though.
Because a well calibrated TV can't show colors darker than #101010 or lighter than #EBEBEB so you won't see any difference between red, green and blue or red, green and blue. There's other reasons too.

Modern TV's and computer monitors on the other hand can use the whole range and often have a higher bit depth too. (i.e. if you can't tell the difference of colors in the words above your screen is not correctly calibrated (or maybe you're color blind, sorry about that).

Post Reply