Converting component YPbPr to S-Video or composite

[ZDragon]

As my Mayflash YPbPr->VGA adapter doesn't support the conversion of interlaced video, I currently can't display any Gamecube or Virtual Console games on my computer LCD screen, as they only run in interlaced video modes on my PAL Wii. Which gives me a black screen with the Mayflash adapter.
Now I don't have the great amounts of money needed to buy an XRGB to fix this problem. But instead there's another possible solution that came to me: using the Mayflash adapter for the 480p video, and using an external adapter such as the Geniatech LCD Supera Color or just my computer's TV card for the 480i/576i video. Yea, now you might be wondering: well, why don't you just do so? Well, I've tried lots of times already to make my own custom Wii cable by hacking with paperclips like described in the Wiki to make a cable that has both component AND composite outputs. I just don't manage though, it won't work for me and I'm kind of fed up with that.

So now I was thinking... okay, if I can't get the composite video out of the Wii, is there maybe any way to convert the component YPbPr output that is on the other end of the Wii cable to S-Video or Cinch? I was thinking that S-Video and YPbPr already shared the  Y line anyway, so that part could be easily done. But if I do only that, of course I only get a black and white image - what's missing is the conversion of the Pb and Pr lines to the S-Video's chroma channel... or alternatively (although that way image quality would be wasted) convert the whole YPbPr thing to a composite (FBAS) signal and get it into my TV card that way. Well, I'd rather like the S-Video solution of course



Any help here would be greatly appreciated!

[ZDragon]

Whoa, no one able to help me with this? Really, I'd appreciate any input a lot... even if it's just a link to a forum where I might just ask instead.

I kind of found out that I first have to convert PbPr of YPbPr to UV of YUV, as U+V=Chroma. If I'm wrong, tell me so by the way
I already know how to do that converting from PbPr to UV (the signal strength differs only by a constant factor, so that really isn't the hard part).

I was wondering now though: how do I combine U and V accordingly to make a chroma signal out of it? Or is it simply not possible? Would it then maybe be possible over Composite only?


PS: Why do I have to disable my firewall if I want to post here? The server gives me a 400 (Bad Request) otherwise O_o.

[Bostich]

PS: Why do I have to disable my firewall if I want to post here? The server gives me a 400 (Bad Request) otherwise O_o.

I don't have any input to offer for your main question (you're going for a DIY conversion, right?), but I had to note that I also have to disable my firewall to post here.  I've never had this problem on other forums and it has always puzzled me.  For a while I had just given up on posting because I didn't know what the problem was.

[Segasonicfan]

http://elm-chan.org/works/yuv2rgb/yuv2rgb1.png

Have fun with that....

Converting component is a bitch  :angry:

-Segasonicfan

[NFG]

PS: Why do I have to disable my firewall if I want to post here? The server gives me a 400 (Bad Request) otherwise O_o.

I've heard this complaint exactly once before.

This server doesn't do anything special.  There are no weird ports in use, it's not even using secure transmissions.  If your firewall's blocking it I'd very much like to know why.

[Segasonicfan]

wth....apparently elm-chan works just went down 1 day after my post...that sucks.  

He better fix it, that site is a very useful resource.

-Segasonicfan

[ZDragon]

Excuse me, but of what use is RGB for me? At least the URL of that link you posted kind of seems like being a YUV to RGB converter, but S-Video uses the YUV color model, doesn't it?

[kendrick]

I think SSF's argument is that converting component signals is more computationally expensive. Any encoder is likely to be generating an RGB signal internally before it produces S-video or composite from the component source. Granted, there are devices that will convert any signal if you're willing to pay for them (I can think of one $3,000 Sanyo device meant for large displays.) But for something homebrew or on the cheap, it's probably not a bad idea to conver to RGB first and then produce the signal you want from that.

-KKC, making dinner plans.

[ZDragon]

The sheet is working actually, seems like remote-linking isn't allowed or something, so just copy it over to your browser's adress bar and it should work if it previously didn't.

So there's actually an RGB to YC converter inside that sheet already, which would be just what I'd need after first converting the YUV signal to RGB. Now I'm wondering about something though: could it be that the Mayflash converter I have (http://www.mayflash.com/vgabox/vga001/vga001.htm) already does the conversion of YPbPr to RGB anyway, even for interlaced video? I know that it's not really in the feature list (there is just written "Supports 480p, 720p, 1080i, and 1080p", so no word of 480i or 576i) but as my monitor just displays a "wrong frequency" warning whenever my Wii switches to 480i or 576i, the signal coming out of that Mayflash YPbPr to VGA converter should still be an RGB signal (although the H-Sync and V-Sync can't be handled by my monitor of course). I also think that because of this line here:
"The device accepts one set of YPbPr inputs and one set of RGB/HSYNC/VSYNC (PC display card output signal) inputs. Based on the input selected, the output will be either a decoded TV or buffered PC video signal."


...well anyway, then I could just easily take the RGB from the monitor cable and work with that, no bitching around with YPbPr to RGB needed then. Right? This would very much simplify things then, as I'd only need the RGB->YC conversion then.



By the way, I really got no clue about where to find all those parts. Any idea for a (preferably European) supplier for important stuff like that "CXA1645P" IC? And are there more simple sheets for that rather "simple" conversion of RGB to S-Video (YC)?

[Segasonicfan]

RGB to S-vid conversion is FAR easier and only requires the CXA1645.  Just do a google search for the datasheet which will give you all the info you need.  It is an obsolete chip but they are sold on Ebay and you can gut them from any Saturn or PSX console.

-Segasonicfan