Modding GCN color encoding between NTSC/PAL

[theclaw]

It's been said that NTSC Gamecubes use PAL-M at 50hz. Then how practical is a color fix circuit to get PAL50?
I don't think I've seen much research on the malformed video signal.

DVI/HDMI mods, component cable, and stuff avoid the issue rather than tackle it.

*Topic title updated to reflect a more general goal.

[Sierron]

The brazilian version of the gamecube (DOL-002 BRA) uses the PAL-M video mode.

PAL-M signals are identical to North American NTSC signals, except for the encoding of the colour carrier. Therefore, PAL-M will display in monochrome with sound on an NTSC set and vice versa.

I don't think there is a fix or an easy fix at all for this.

edit:
Afaik only the gamecube menu use the PAL-M mode and the games are in NTSC60. Reading the article some more PAL60 and PAL-M would not be compatible - so no easy fix.

I can only guess that was an oversight and that's why they released an additional revision just for brazil?

[theclaw]

Sorry about that. I meant to say PAL50.

I don't know what 50hz games do on a brazilian gamecube.

[novenary]

I think it's a minor issue, there is no point in using 50hz mode anyway, almost all pal games support 60hz mode (some even enforce it like metroid prime 2).
I'm pretty sure s-video doesn't suffer from this issue either so considering it's a cheap and vastly superior alternative to composite, the choice is easy.

[theclaw]

Man, live a little. The journey is the fun part.
s-video doesn't look promising. It too uses a color subcarrier.

[Extrems]

The choice is either NTSC 50 Hz or PAL-M 50 Hz.

I don't know what 50hz games do on a brazilian gamecube.

The same thing as on an American one.

[novenary]

Man, live a little. The journey is the fun part.

Believe me, I'm on a journey that is much more fun.

[theclaw]

The choice is either NTSC 50 Hz or PAL-M 50 Hz.

Interesting, how do you enable that? I wasn't aware of a way of getting NTSC 50 Hz from a gamecube.

Why not humor me, and point in the right direction to encode PAL-M 50 Hz into PAL 50 Hz?
I may lack soldering ability but I can ogle at diagrams and sigh.
Or if not feasible then consider the topic closed.

It would seem the key part here is a crystal oscillator. Making the 3.58MHz subcarrier become 4.43MHz.

[novenary]

The difference is not in frequencies (these are for the entirety of the signal) but in the encoding (format) of the actual video data. Transcoding that in real time would make things even worse than the already disgusting quality of composite.

[theclaw]

The difference is not in frequencies (these are for the entirety of the signal) but in the encoding (format) of the actual video data. Transcoding that in real time would make things even worse than the already disgusting quality of composite.

I don't follow. PAL-M and PAL are both encoded in PAL.

[novenary]

An NTSC console is incapable of outputting PAL video, it's just NTSC without color, and in 50Hz. Even if you configure the video encoder in PAL or PAL-M mode, you won't get proper output because it just wasn't made for it, unlike the Wii. A PAL or PAL-M console will output the proper color signal, which is fine as long as your TV supports PAL. The Xeno menu will show up in black and white on an NTSC console, black and blue on every other console.

[theclaw]

Now I'm more curious. That's a bit different from Extrems' answer.

Anyway, how do you configure the video encoder? A useless outcome is still educational in giving the console more exhaustive documentation.
On the other hand if had access to such Gamecube technical docs, I'd have been able to learn all this on my own.

[novenary]

http://libogc.devkitpro.org/video_8h.html

[theclaw]

http://libogc.devkitpro.org/video_8h.html

Thanks. For sure heaps of enlightenment in there.
The other thing I would've needed to reach this conclusion myself, is a device to analyze the signal.

[novenary]

Correcting myself here, according to Extrems, DOL-002 is the exact same hardware as an NTSC DOL-001 unit, but with a different IPL. So PAL-M mode will work fine, as long as the decoder (your TV) supports and detects it.

[Sierron]

If I'm not mistaken, all the gamecubes are identical (except for hardware revisions) and only the IPL set things up differently for reach region.

As soon as my japanese cube boots into swiss it displays PAL in 50hz without an issue and seems to be identical to my normal PAL cubes.

[Extrems]

No, PAL consoles have a different encoder that only output PAL.

[theclaw]

Correcting myself here, according to Extrems, DOL-002 is the exact same hardware as an NTSC DOL-001 unit, but with a different IPL. So PAL-M mode will work fine, as long as the decoder (your TV) supports and detects it.

Perhaps. What TVs allow manual override of format standards, by letting you choose whether to decode video as NTSC, PAL, PAL-M, etc?
PAL-M at 50hz sounds like no problem then.

If I'm not mistaken, all the gamecubes are identical (except for hardware revisions) and only the IPL set things up differently for reach region.

As soon as my japanese cube boots into swiss it displays PAL in 50hz without an issue and seems to be identical to my normal PAL cubes.

Not a bad idea. I haven't played around in swiss much.

No, PAL consoles have a different encoder that only output PAL.

That could work too, salvage a PAL console for its encoder. I don't know if it'll just drop in.

[novenary]

Perhaps. What TVs allow manual override of format standards, by letting you choose whether to decode video as NTSC, PAL, PAL-M, etc?
PAL-M at 50hz sounds like no problem then.

How about a pal only TV ?

That could work too, salvage a PAL console for its encoder. I don't know if it'll just drop in.

It won't just drop in, there is some circuitry on the analog side that is different. Don't destroy consoles to find out, it'd be better to just use a pal unit instead.

[theclaw]

Circuitry differences, I'm all ears.
I already own a component cable to test 50hz component. While yes buying a pal unit instantly gets me pal50, my objective is research on the 50hz mode of ntsc units.

I've never used an imported pal or pal-m tv. from what I understand a pal tv is unlikely to accept pal-m, and a pal-m tv is unlikely to accept 50hz.

[novenary]

As Extrems said, a PAL TV should be mostly fine with it.

Using a component cable or gcvideo is pretty much an encoder swap too, but hooked up to the external port.

[Sierron]

PAL-M doesn't work on normal PAL TV's.

[novenary]

Ah right, it was pal-n.

[theclaw]

Ah right, it was pal-n.

It gives me hope. Nobody is going to miss one composite cable we hack an experimental pal-m to pal50 circuit into.

[theclaw]

How much of the GCvideo specifications are public knowledge? Its analog version could be used as a basis for a original new composite/svideo DAC, able to grant NTSC/PAL color switching functionality to all Gamecubes.

Although this would only work on PAL systems (so it doesn't directly solve the original question) sending the existing RGB to a separate encoder is sure to work with off-the-shelf parts.