Gamecube 480p over component: colors worse than 480i?

[Kadano]

Hello, I use official japanese Gamecube component cables to feed YPbPr to my Avermedia H727 (PCIe capture card).
Still images look better in 480i than in 480p.
480i (Melee’s Smooth Display is set to OFF):

480p (Smooth Display OFF):


Note that the colors are shifted horizontally by 2 or 3 px. This effect is much more pronounced on 480p than on 480i, although it’s present there as well.

Here is a zoomed in comparison:


It’s highly unlikely my video card is at fault as my reference monitor (Sony PVM20M7MDE) shows the exact same artifacts.

What I want to find out is whether the Wii component cables have the same color problems and whether my Gamecube component cables might be damaged.
So if you have component cables, Melee and a component recording device, please upload a similar image so I can compare it!

If my component cables work just as well as any other, I suspect that YPbPr just isn’t as color perfect as RGB. Or the Macronix chip inside does a worse job at encoding in YPbPr than in RGB – when I plug my Gamecube cable modded for DSUB / VGA into my LCD monitor, there are no artifacts at all and the picture looks almost like the Dolphin emulation reference.

[tueidj]

The actual framebuffer in the gamecube uses YUV data. For that reason alone Dolphin should not be used as a reference.
A lot of capture cards give worse results capturing in 480p rather than 480i, they're meant to sample the signal twice as fast (a 480p scanline has half the period of a 480i scanline) but I think most of them just sample at the regular rate and interpolate every second sample which gives a blurrier picture. Haven't seen a chroma shift like that before but it would be caused by the card rather than the cables.

[Kadano]

Thanks for the reply. Still, I’m not quite convinced it’s just my card because the problem also persists on the reference monitor. I doubt Sony would be able to sell reference monitor that can’t display YPbPr properly.

[novenary]

YUV isn't as color perfect as VGA because you are carrying 5 signals (three color space specific signals + hsync and vsync) in 3 vs 5 conductors resulting in interference . Also the former has to be processed in order to be usable by the display since all of these have an RGB panel. The more you mess with the signal the more you damage it.

[Kadano]

Thank you, so basically the YPbPr color model is the limiting factor?

I guess then the only way to improve my setup is to go for the Micomsoft SC-512 card and use its VGA recording + passthrough capatability.

[tueidj]

The cube's YUV framebuffer is YUY2, so chroma samples are shared between each pair of pixels... that would account for a small amount of chroma blurring (especially with reds or blues) but not a large shift like your screenshots show.

[Kadano]

Maybe the YCbCr → YPbPr conversion in the MX chip adds to the color problem?

I looked at videos of streamers who use component in, for example Team Sp00ky who uses elgato Game Capture HD, and the blurring looks very similar there.

[Extrems]

Taken with the Blackmagic Intensity Shuttle USB 3.0

Wii 480i


Wii 480p


GameCube 480i


GameCube 480p

[Kadano]

Thank you very much! Those look amazing. It should be my component cables that cause the problem then, I guess? I ordered a D-Terminal to component adapter from Solaris Japan, hopefully I’ll get better colors this way.

Oh, by the way: For the Gamecube ones, did you use the standard official component cable?

[Kadano]

It was painfully obvious, but of course it’s the H727’s fault. I should have gone for Micomsoft’s XCAPTURE-1 from the start.

Also, the adapter I ordered from Solaris Japan is this one: http://www.solarisjapan.com/d-terminal- ... able-male/
It works like a charm. No difference to my official Nintendo Gamecube component cable.

[Kadano]

The actual framebuffer in the gamecube uses YUV data. For that reason alone Dolphin should not be used as a reference.

Does that affect PAL RGB output over SCART as well?