Wii; multiple video chips?

[zedrein]

I was readin' about the Gamecube and Wii's analog component video capabilities and noticed that they both use an additional chip for the component video output mode (CMPV-DOL Chip) with the only difference being the chip lives inside the Wii while it exists inside of a cable for the GCN. Is this an entirely new chip separate from the main video chip, or does it exist just so those consoles can output progressive scan? I ask this because I have had a little trouble with the output of video on my Wii from the two NTSC standards (composite and S-video) there is some slight breakup in the picture when playing Virtual Console titles (could be emulation discrepancies) and it occurred to me that having a more direct or different signal source to draw from could reduce my problem.

[l_oliveira]

GCN has a CVBS/S-Video only encoder.  The Wii one does everything  hence why it's bigger.

The external one on the GCN is connected in parallel to the one installed internally. When a 31khz mode is selected (progressive scan) the internal one is disabled and only the external one is used.

I suppose they did that on the GCN for cost saving. On the wii they just put all functions on the same chip.

[zedrein]

Interesting, so the chip actually simply enables progressive resolutions? It's not an entirely different GPU?

[l_oliveira]

It's just a Digital to Analog converter with some fancy functions (like composite video encoding, YCbPr output and RAW RGB).
The Wii system software is programmed to disable RGB support if the console is setup for NTSC video output.
The wii mother boards are identical in all regions.  Progressive (The Wii can't handle anything more than 480p due to that chip being not compatible with faster raster) 480P is supported.

[zedrein]

Hey thanks! But why can't the main video chip do all of that? It's just interesting that the Wii requires an additional chip for those functions.

[Link83]

The external one on the GCN is connected in parallel to the one installed internally. When a 31khz mode is selected (progressive scan) the internal one is disabled and only the external one is used.

[EDIT - Please disregard the next paragraph, I was wrong   Please see below replies]
Actually, I am pretty sure the the GameCube's internal DAC is not disabled at all when both DAC's are connected, as the Composite video signal from the 'ANALOG AV OUT' port was still used when building GameCube RGB Scart cables for NTSC GameCube consoles by modifying GameCube Component/D-Terminal cables:-
http://web.archive.org/web/20080523201404/http://www.mmmonkey.co.uk/console/nintendo/gc-rgb.htm
The Composite video signal from the analog out was still needed for the C-Sync. Please feel free to correct me if i'm wrong though

Zedrein, if your interested I posted a picture of the Wii's internal DAC in this thread:-
http://nfggames.com/forum2/index.php?topic=3578.0
Its worth noting that the Wii's DAC also handles audio as well as video.

[l_oliveira]

The internal one is disabled only when progressive scan is enabled. As I said on my previous post. It's required to not cause damage to television sets.
Well, what I say can be only applied top NTSC machines. I know nothing about PAL machines.

[Link83]

The internal one is disabled only when progressive scan is enabled. As I said on my previous post. It's required to not cause damage to television sets.
Well, what I say can be only applied top NTSC machines. I know nothing about PAL machines.

Ah apologies, I should have read your sentence more carefully I am sure you are correct, since disabling the internal DAC when progressive scan is enabled would make sense (Although unfortunatly I have no way to test it)

...Although the GameCube's internal DAC chip also handles the audio, so I guess only the video part of the DAC chip is disabled when enabling progressive scan?