Wii - YPbPr through SCART

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shawly
Posts: 20
Joined: Sun Nov 27, 2016 5:27 pm

Wii - YPbPr through SCART

Post by shawly »

Hi,

so I've been wanting to use my RGB SCART cable from RGC with my OSSC and my CRT without switching between SCART and Component cables. I've read that the OSSC also accepts YPbPr through SCART, so I've tested this with my Playstation 2 where I could switch between YPbPr and RGB in the system menu.

The Wii doesn't have an option to switch between YPbPr and RGB though software, technically the BootMii config does but I don't want to switch SD cards either to edit the config every time.
Therefore the easiest way is to bridge pin 8 and 10 so it outputs YPbPr as it says here: https://gamesx.com/wiki/doku.php?id=av: ... _av_pinout

Then I pulled out a cheap RGB SCART cable for the Wii, disassembled the AV plug and bridged said pins and the Wii indeed put out YPbPr through SCART which the OSSC recognized.
Now I wanted to do the same thing with my RGC cable and integrate a small dip-switch so I can switch between RGB and YPbPr easily.
But the issue here is, that the AV plug is molded plastic so I can't pull it apart to get to the pins, hence I disassembled my Wii and integrated the switch into the console itself (soldering it to pin 8 and 10).

Even though theoretically this should work, it doesn't.. Wenn the switch is flipped to ON it bridges both pins, forcing the Wii to YPbPr, but the OSSC doesn't get any signal whatsoever!
Switching it back off, the Wii properly outputs RGB without any issues. I've ruled out the switch, the issue can be reproduced by directly bridging the pins.

The strange thing is, the cheap cable kinda works, I've unsoldered the bridged pins in the cheap cable and tried it and it produces proper YPbPr which is recognized by the OSSC.
BUT if I switch to RGB with the cheap cable, it does output RGBS but the image is pink/violet, so it seems like Green is missing.

I'm really confused as to what is causing this strange behavior.. Especially why the RGC cable isn't producing any YPbPr while the PS2 one is working fine!
Both the Wii and the PS2 cable have the exact same sync strippers from RGC and they are wired exactly the same.

Anybody has an idea what could be causing this?

Edit: OK so I found the reason why my PS2 cable works but the Wii cable doesn't, I haven't read the diagrams properly..
The PS2's mapping is as follows R(Pr) G(Y) B(Pb), but the Wii's mapping is actually R(Y) G(Pb) B(Pr) which I found out when looking and the cheap cables wiring and see that RGB is completely wrongly wired, which explains the missing green when I'm using the cable with RGB. And the person who changed the wiring was probably ME because I wanted to use the cable with YPbPr so I rewired it at the beginning of the year or so, but I don't a single memory of doing it, I thought I just bridged the pins... This means the hardmod I did on my Wii is pretty useless. Unless I get the cable also modded by switching around the pin layout on the scart plug.
Last edited by shawly on Sun Oct 06, 2019 3:30 pm, edited 1 time in total.
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Link83
Posts: 342
Joined: Tue May 21, 2013 2:39 am

Re: Wii - YPbPr through SCART

Post by Link83 »

Whilst i'm not sure why your getting different results with each cable, i do know that this unfortunately isn't likely to work out :(

Unlike the PS2, PS3, OG Xbox and Xbox 360 which all have the pinouts between RGB and YPbPr color matching, e.g:-
R=Pr
G=Y
B=Pb

The Wii (and by extension the Wii U) uses a completely different pinout:-
R=Y
G=Pb
B=Pr

Its likely the OSSC is expecting the signals to match the plug colors like all the other systems, but that's just not how the stock Wii's output is setup unfortunately.

I guess you could fit a switch in the cable to swap the signal order, or you could also install a WiiDual which uses the same matching signals as other systems (Thats one of the reasons why the WiiDual requires a custom RGB SCART cable)
Last edited by Link83 on Sun Oct 06, 2019 3:49 pm, edited 1 time in total.
shawly
Posts: 20
Joined: Sun Nov 27, 2016 5:27 pm

Re: Wii - YPbPr through SCART

Post by shawly »

Link83 wrote: The Wii uses a completely different pinout:-
R=Y
G=Pb
B=Pr
Yeah, I just found this out 10 minutes ago. :lol: Wasted my whole day with this, where as I should've just compared the pinouts of the PS2 and Wii AV plug and I would've found this out immediately.
Since I already modded the SCART plug with a small switch to toggle C-Sync on the cable, I guess I'm going to add three additional switches to the SCART plug.

Edit: FINALLY
Image

Just finished adding these switches and tried it out, both RGB and YPbPr work perfectly fine and the image quality is notably better with the RGC cables over the cheap cable, so this was a full success!
Since I was able to integrate the switches into the SCART plug so neatly, there is also no problem with neighbor SCART plugs on my Hydra2. Really happy I finally got this working, though a software solution would've been preferrable IMO.
Classicgamer
Posts: 873
Joined: Thu Sep 11, 2014 3:37 pm

Re: Wii - YPbPr through SCART

Post by Classicgamer »

I'm not familiar with the EU wii (the American one doesn't output RGB at all) but, if I understand the issue properly, couldn't you use a cheap adapter like this?

https://www.ebay.com/itm/RGB-SCART-ADAP ... SwhQhY7G1t


These dump adapters don't do any transcoding. They are just dumb plug adapters but you could switch the colors from a regular component video cable to match what you need potentially.
shawly
Posts: 20
Joined: Sun Nov 27, 2016 5:27 pm

Re: Wii - YPbPr through SCART

Post by shawly »

Nope the adapter isn't what I needed, since I wanted to be able to switch between RGB and YPbPr with a SCART cable, since my CRT doesn't support YPbPr. But when I'm playing via the OSSC on my monitor or tv, I want to be able to use 480p which isn't possible via RGB since the Wii will always output 480i when not connected via component.

The modification I made on my Wii and SCART cable allows me to switch between RGB and YPbPr without having to switch cables at all.

As Link83 mentioned, the WiiDual would also be capable of this, even though I'm not sure if you can switch between YPbPr and RGB via WiiDuals menu, if not it would still required the switch for bridging pins.
But my Wii revision (RVL-CPU-01) is not compatible with the WiiDual, which would mean I'd need to spend money on a new Wii apart from the price of the WiiDual itself. I also wouldn't have any need for HDMI since I already got my OSSC and I don't record gameplay nor do I stream, so for me it's not really worth the money for my purpose.

If there was a less expensive analog only variant of the WiiDual with digital audio like the GCVideo Lite I'd be all in, getting digital audio from all my retro and 5th gen consoles would be really nice.
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