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Old 24 January 2019, 16:01   #1
Lord Aga
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The Great RGB to Component Mystery

Oh, I'm on a roll today with the topics

But this is a rather big issue. Why don't we have ready-available RGB to component adapters/cables? Component connectors are kinda more widely available on various screens (TVs to monitors). Certainly more common than SCARTs.

Now, I know there were attempts, and I have followed several projects that tried to tackle this, but they have all mysteriously disappeared/stopped/vanished.

Some of our heavy hitters, namely Kipper and Stedy had a crack at it, with a hearty help from Zetr0 (man I miss that guy ). Several threads are full of progress, plans, tests, pics, videos, and then they just fizzle out.

Narmi had everything done with his adapter, and then just mysteriously stopped visiting the board.

Kjmann reported the completion of his adapter, posted videos, and announced the partnership with Amigakit. Amigakit confirmed this and they were looking forward to stocking the adapter. That thread also mysteriously ends without any explanation.

The only explanation I do remember is Kipper saying that adapters work on some TVs and not on others and it's making him trouble.

Is there an anti-component conspiracy going around? I would like to hear some opinions (on the technical side of the adapter more than on the conspiracy theories).
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Old 24 January 2019, 16:10   #2
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Component is sufficiently different from RGB as to require active conversion. And to be honest, I don't think it's as common as RGB SCART, at least from my own experience. If you're going to have an active conversion, you might as well just go all the way to HDMI I guess...
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Old 25 January 2019, 01:28   #3
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There was this that was on ebay for a while:
https://gglabs.us/node/983
Also the Amiga Video slot version:
https://gglabs.us/node/2014

I was going to pick one or both up but it seemed to me they were far too expensive, then after I said "screw it, it's only money" they were unavailable. Basically the same reason why I don't have a Deneb. They have schematics available though for the Video slot version and gerbers, schematics and everything to have the RGB port version built. I guess the reason they stopped making it is the same as Kipper and others, some TVs don't support 240p mode any more and probably no way of knowing whether your TV does or not. Like with monitors just buying one at random and returning it is even less practical with TVs.

Last edited by grelbfarlk; 25 January 2019 at 02:07.
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Old 27 January 2019, 15:35   #4
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Hi,

No mystery, 240p/288p video can't be used or easily 'faked' to 480p/576p video. YPbPr component video needs a tri-level sync, this could be created (as retro systems do not support this) but it will not fix the issues. I tried Amiga RGB to YPbPr using a video decoder/encoder combination, whilst it worked, the screen scrolled vertically. The chipset I used had trouble handling 288p but outputting 576p.

I did convert Y/C (S-video) to YPbPr, it also had the vertical scrolling, feeding it into a GBS-8200, which has a timebase correction facility, worked. I posted a screenshot here:
https://ianstedman.wordpress.com/gbs-82xx-experiments/
I used the Atari 7800 for this test.

The GGLabs, Kipper2K, Narmi and I think Kjmann designs, apply a simple analogue conversion to the colour signals, based on this: https://www.analog.com/en/design-cen...onversion.html

They do nothing for the sync or to correct the timebase. These circuits will work with some TVs but your mileage may vary, this key concept is why they are not generally available.

I have looked at RGB to HDMI with timebase correction, it can be done but a solution would not be cheap. Some HDMI devices need NDAs in place before I can get the full details. As I try and make all my projects openly available it is a concern.

The GBS-8200 is an Ok board, switch off the motion estimation, de-clock the SDRAM and you have a reasonable picture. I'd struggle to make a solution for RGB or Y/C to SVGA/HDMI <£100.
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Old 28 January 2019, 04:20   #5
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It’s a bummer more RGB to Component solutions are not available for Amiga.
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Old 01 February 2019, 11:15   #6
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What if instead of trying to convert RGB -> YPbPr you converted Y+BR -> YPbPr? The A500, A2000, and CD32 have native luma connections, and there are not-very-difficult hacks for other models (usually first made as a necessary part of an S-Video mod). You could do the B-Y and R-Y with just a few components, with sync already nicely baked into the Y line.

Last edited by AmigaHope; 01 February 2019 at 11:21.
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Old 02 February 2019, 14:33   #7
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Thanks for all the input guys. Especially to Stedy for some first hand experience info!

So basically the simple way is too unreliable, and the complicated way is too complicated and we might as well go for HDMI, as Daedalus said.

I would still like to get my hands on one of those hit-and-miss adapters, just to play around with my screens and see what happens. Does anyone have any idea how to get one?
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Old 02 February 2019, 15:01   #8
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As Australian TV's don't have SCART, I use a Cypress RGB to YUV converter. Can't recommend it enough, the picture quality is flawless when displayed on my 68cm flat screen Trinitron CRT.
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Old 02 February 2019, 15:08   #9
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Linky-dinky pretty please
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Old 02 February 2019, 15:19   #10
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I can't suggest a good place to buy them from as it's discontinued but the model is CSY-2100. Analog Devices manufacture RGB to YUV IC's, you may be able to get a couple of free samples from them and make a small circuit on a veroboard.




Edit: There's also a couple of RGB to YUV converters designed for arcade boards that would be suitable. Namely the JROK and NeoBitz. These devices produce an extremely high quality picture, far better than that GBS-8220 rubbish.

Last edited by Hewitson; 02 February 2019 at 15:32.
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Old 06 February 2019, 05:06   #11
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Why not just do a Sammelsthreadbestellung and build 10 or so of the gglabs design? I'm in for two.
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Old 06 February 2019, 13:27   #12
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The 'Sammelsthreadbestellung' part got me honestly laughing
We would, of course, need a Dingmachermeister. Someone who's got the skills and the time.

If we can find such a guy, I'm game.
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Old 07 February 2019, 02:08   #13
grelbfarlk
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Quote:
Originally Posted by Lord Aga View Post
The 'Sammelsthreadbestellung' part got me honestly laughing
We would, of course, need a Dingmachermeister. Someone who's got the skills and the time.

If we can find such a guy, I'm game.

Looks pretty easy to assemble. I'll try to price it out. There's still the problem of finding female DB-23s cheaply.

Something like $20 in components from Digikey per board plus a PCB and a DB-23 connector. Worst case say the PCB costs $10 per, plus another $15 for the DB-23 made of Invisibilium.

Last edited by grelbfarlk; 07 February 2019 at 02:48.
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