PAL Gamecube c-sync

[Bad_Ad84]

Digital output uses a DAC. Its in the cable and converts to YPbPr so your tv can actually "understand" what its being sent (i.e. component video)

[LocalH]

Hence why I'm such an advocate in favor of putting GC's digital output to use. For 480p games there would no longer be any DAC, ADC, composite video, or YPbPr involved. Purely digital (YCbCr) all through to the TV.

I'm not sure how many TVs accept interlaced digital however...

You would need something to convert the digital output (which, AFAIK, is proprietary in the sense that it doesn't use any known standard signaling) to whichever input you wish to use (DVI/HDMI, analog YPbPr, RGB, etc). Doubtful that you'll have any use out of "YCbCr" directly which AFAIK is mostly used with Firewire or SDI, the latter of which is not found on any consumer set and the former is not as widely found as in the past.

GCN Digital A/V -> DVI/HDMI would be very handy and should output the best possible quality. Wonder if the video chip can be forced to higher scanrates in a similar way to the PS2's? Would be interesting if it were possible to make "mode promotion" homebrew similar to GS Mode Selector on the PS2.

[Lum]

Digital output uses a DAC. Its in the cable and converts to YPbPr so your tv can actually "understand" what its being sent (i.e. component video)

Using a DAC for that purpose means the resulting output is no longer digital. Its source video has waited years for someone to sufficiently document and harness in digital form. My idea isn't without precedent. The audio portion (which Nintendo never released a cable for) is already known how to convert into optical.

[fathertime]

Is the checkerboard static or does it roll or shimmer like composite video artifacts?

On N64, the checkboard is static
On the GameCube though the checkerboard rolls to the left

Using luma instead of composite video gets rid of the checkerboard on GC as well?

The PAL gamecube doesn't have either CSYNC or LUMA from the multiout so there is nothing you can use to fix it by replacing composite video for sync.

Dithering can be tested by putting a low value capacitor in parallel with the TV input.

Last weekend I ordered one of these and one of these. I'll post some pics when they arrive. You never know, maybe it's just the cable... If the official cable doesn't fix it I'd be happy to try out this suggestion. What value cap should I use?

[Lum]

To think the Megadrive vertical bars are less annoying than a checkerboard.

[Bad_Ad84]

Using a DAC for that purpose means the resulting output is no longer digital. Its source video has waited years for someone to sufficiently document and harness in digital form. My idea isn't without precedent. The audio portion (which Nintendo never released a cable for) is already known how to convert into optical.

The cable uses a DAC and converts its to component. The raw digital output wont work "as is" on anything. After all, YPbPr is analog =/

No one seems to know how the signal works to use it for anything else unfortunately :(

[gorgyrip]

On N64, the checkboard is static
On the GameCube though the checkerboard rolls to the left

Same for me.

[fathertime]

I think this thread has wasted everybody's time :) An official sealed Gamecube RGB cable arrived today and guess what? It looks fantastic! No checkerboard crosshatch and it rivals the component cable display through the wii. The 3rd party RGB cables may have worked on CRT but for Samsung, go official only! I ordered my official cable from this guy on ebay - cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=170824048231

Case closed!

[Bad_Ad84]

Not entirely....

I want to know WHY it works.. Maybe different values on the resistors in the cable?

[fathertime]

I'll open the 3rd party and official cables over the weekend and take some pictures - that's assuming all the parts are in the scart end and not the multiout end...

I can tell you though, the official cable is a lot thicker and heavier. The 3rd party one even feels cheap in comparison.

[Bad_Ad84]

But why does the 3rd party cable work fine on all other tvs and works fine with csync on a samsung?

You have only caused more questions :)

[link83]

Wish I had seen this thread earlier, as I looked into this topic years ago so perhaps I can help a little :)

Of course NTSC cubes having it can help... you can see which chip C-SYNC is coming from, by tracing from the AV connector and see if the same exists on the PAL console...

If it does, he can just cut Composite video at the AV connector and rewire C-Sync to it.

I'm afraid it wont help to compare PAL and NTSC GameCube motherboards, since they actually use different custom ROHM combined Audio+Video DAC/Encoder chips.

PAL GameCube uses 'AVE P-DOL' which outputs RGB and Composite Video:-

NTSC GameCube uses 'AVE N-DOL' which outputs S-Video and Composite Video (Unsure if it does actually output C-Sync?):-


So unless there are some unused pins on the 'AVE P-DOL' which output C-Sync or S-Video then i'm afraid your out of luck :(
(I also made a partial pinout of the DAC's which I will try and dig out and tidy up if anybody is interested?)

I'll open the 3rd party and official cables over the weekend and take some pictures - that's assuming all the parts are in the scart end and not the multiout end...

I can tell you though, the official cable is a lot thicker and heavier. The 3rd party one even feels cheap in comparison.

I already dissassembled all the official Nintendo GameCube cables years ago:-
http://nfggames.com/forum2/index.php?topic=3203.0

The PAL GameCube and PAL N64 both need a 75ohm resistor to ground and 220uF capacitor in series (Positive leg always towards console, negative leg towards TV/Display) on the Composite Video line, otherwise you can expect video quality problems like those shown in the above pictures. I even added this information in the gamesx wiki:-
http://www.gamesx.com/wiki/doku.php?...intendomultiav
Most third party Nintendo MULTI OUT cables are missing these components, since they are mainly designed for the NTSC market, not PAL. The official PAL GameCube Composite cable and official PAL GameCube SCART cable have both these components on Composite video (Just to be awkward the official SCART cable has one component located in each end of the cable - 75ohm resistor hidden inside MULTI-OUT plug, 220uF capacitor on SCART plug PCB)

Of course cable quality and adequate shielding can also play a part ;)

The cable uses a DAC and converts its to component. The raw digital output wont work "as is" on anything. After all, YPbPr is analog =/

No one seems to know how the signal works to use it for anything else unfortunately :(

Actually the signal format has been understood for a long time, since its well documented in Nintendo's patent:-
http://www.google.com/patents?id=Rk0...page&q&f=false
Page 42/Sheet 38 shows the pinout of the Digital AV Port:-

Which I helped update on the gamesx wiki:-
http://www.gamesx.com/wiki/doku.php?...tendodigitalav

Page 22/Sheet 18 shows the digital signal format.

Theres plenty more information in the patent as well.

All it would take is someone with the right technical knowledge to use an FPGA to create a proper HDMI cable for the GameCube, much like how marshallh is adding VGA to the N64:-
http://forums.benheck.com/viewtopic.php?f=58&t=43034
Only the GameCube wouldnt even require any soldering if we could find a company willing to make the custom Digital AV plugs.

[Lum]

Hmm, doesn't appear it'd be a complicated FPGA. YCbCr is acceptable under the HDMI standard.

[Calpis]

Not a "complicated FPGA"?? Have you worked with FPGA? Designed a PCB for one? Using high-speed transceivers? Done transmission line analysis? Designed any termination circuit? Designed controlled impedance traces? Written a TMDS or any 8b/10b encoder? A SDRAM controller? Deinterlacer/upscanner? Designed DC-DC converters? Soldered VQFP? Soldered FBGA?

Everything is complicated. Even without upscanning 480p requires 270 MHz serialization = 810 MHz minimum analog bandwidth to get anything resembling a square wave.

[gorgyrip]

My cable is made like this:
http://members.optushome.com.au/evil...t/gamecube.png

[Bad_Ad84]

As is mine.

[fathertime]

Last weekend I ordered one of these and one of these.

The second RGB PAL Cube cable, this time from retro-access.com, arrived yesterday and unfortunately it is also no good. There is no checkerboard pattern (which is great) but the screen is way too dark. I opened it up and it only has one capacitor in it (on the composite line, none on the RGB lines). So once again a failure for a 3rd party cable. It seems nobody but Nintendo can get it right.. So glad I picked up the official one now

[Calpis]

Termination is very important in video. There will always be a 75 ohm parallel terminator in the TV, but video sources can have series, parallel or no source termination. It sounds like without the right PAL cable there is no source termination which means that any signal reflected will interfere with the source.