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Author Topic: RGB out of an Amiga into the composite inputs on a HDTV?  (Read 3507 times)

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Offline grover45Topic starter

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RGB out of an Amiga into the composite inputs on a HDTV?
« on: September 25, 2004, 06:03:24 PM »
Is this as simple as getting redmonds cable to make one for me
or will this just not work?
 

Offline Ilwrath

Re: RGB out of an Amiga into the composite inputs on a HDTV?
« Reply #1 on: September 25, 2004, 07:57:57 PM »
COMPOSITE inputs?  You don't even need a custom cable.  Just use a standard RCA cable from the composite video out on your Amiga, if it's an A600/1200.  If it's any other Amiga model, just use an A520 adaptor to give you a composite out port.

Are you meaning COMPONENT video inputs (Y-Cr-Cb)?  If so, then there are generic adaptor boxes out there that should work with a little cable splicing, but they run around $80.  Seems a bit expensive to me.  I've thought about making my own, but just haven't had the time or ambition, yet.  It should be a simple task, as you wouldn't have to touch sync.
 

Offline leirbag28

Re: RGB out of an Amiga into the composite inputs on a HDTV?
« Reply #2 on: September 25, 2004, 09:28:08 PM »
@Ilwrath


hmmmm............can you really connect those Y-Cr-Cb cables on the Amiga to be able to connect it to a Projector or HDTV?  why hasnt anyone done this?  I have been wanting to do it to get an even crisper picture than S-Video...........I once used those Toaster RGB spliut cables with the RGB and SYNC BNC connectors thinking it would work.............it didnt :-)

Also tried a VGA version of that Cable and it didnt work...........why the heck does it work on a PC?  when I try on the Amiga it wont work.
CD32 is actually the best Amiga ever made by Commodore!...
 

Offline Ilwrath

Re: RGB out of an Amiga into the composite inputs on a HDTV?
« Reply #3 on: September 25, 2004, 10:29:12 PM »
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hmmmm............can you really connect those Y-Cr-Cb cables on the Amiga to be able to connect it to a Projector or HDTV?


I would think.  You can make a Y-Cr-Cb signal out of Analog seperated RGB signals (basically what the Amiga outputs).  There are devices that'll do it that are currently for sale.  And heck, google being my friend, here's the schematics for one.  http://elm-chan.org/works/yuv2rgb/report.html
You actually want the bottom link from that page - RGB->YUV adaptor (Diagram 4).

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why hasnt anyone done this?


I don't know... Maybe they have, and they're just keeping quiet.  Or maybe they're all like me and too lazy to build the thing and try it.  ;-)

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I once used those Toaster RGB spliut cables with the RGB and SYNC BNC connectors thinking it would work.............it didnt


No, that's all the information you need, but Y-Cr-Cb uses different balancing of it.  Instead of straight-up analog Red, Green, and Blue information, you need a Luminance (Y), along with Chroma information for Red (Cr) and Blue (Cb).

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Also tried a VGA version of that Cable and it didnt work...........why the heck does it work on a PC?  when I try on the Amiga it wont work.


??? I'm not following what you're saying here...

You can't use a HD-15 -> 4BNC cable to go from a VGA PC Signal to a component video.  Both the Sync and the encoding would be wrong.  The old HD-15 -> 4BNC cables were for connecting newer PCs to older Sun/SGI monitors, which used seperated RGB.  

If you used a VGA -> Component video converter box, it would, indeed, work on a PC, but not an Amiga.  This would be because the converter box would be expecting a 31khz VGA signal, while the Amiga would be producing a 15khz one.... The same reason a stock Amiga won't work on a PC/VGA monitor with just the little silver box.
 

Offline grover45Topic starter

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Re: RGB out of an Amiga into the composite inputs on a HDTV?
« Reply #4 on: September 26, 2004, 01:06:28 AM »
I was actually talking I guess about the 1000, 2000 and 3000 rgb outs (maybe the 500, 1200 too).  I realize that the 4000 and 3000 (which had both) had a vga output.
 

Offline Ilwrath

Re: RGB out of an Amiga into the composite inputs on a HDTV?
« Reply #5 on: September 26, 2004, 02:41:12 AM »
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I was actually talking I guess about the 1000, 2000 and 3000 rgb outs


Actually, all stock Amigas use the same 23-pin RGB output with 15khz analog RGB sync signal.  (With the exception of the A3000 which also has a HD-15 port and can be switched between 15khz and 31khz analog RGB sync.)

The A520 adaptor option I linked to will work to give composite video output on any Amiga.  (You don't need it on the A600/1200, as they already have a color composite video output built-in)

The schematic I linked to should be fairly easy to build into a component video output on any Amiga. (though I haven't tried it.)

So, to recap, these informations are true for ALL Amigas, including the 500, 1000, 2000, 2500, etc...