Stedy's RGB to SCART cable

[orange]

perhaps this is obvious or offtopic, sorry...
don't forget to turn off overscan in TV.

[ShK]

I have a Keene APTUS 1 RGB to component video convertor. I would like to connect it to the Amiga, but I don't get a component picture out of it.



http://www.syncblaster.com/APT1%20instructions.pdf

I have tested the cable connection, which is in the first post.

I also have tested the negative composite sync connection ( -0,7 - 0V ), like this:





I tested now also to connect the scart pins 8 and 16, but I don't think that APTUS1 needs them.



Does anyone have experience of APTUS 1 RGB to component video convertor? What kind of cable it needs with the Amiga?

[dJOS]

Try a different tv before you write off the converter as some tv's don't like the Amiga sync - some rbg-yuv converters simply don't work with Amiga rgb so that is still a possibility.

I have one that does and it was only $50 on eBay.

[ShK]

Originally Posted by dJOS

Try a different tv before you write off the converter as some tv's don't like the Amiga sync - some rbg-yuv converters simply don't work with Amiga rgb so that is still a possibility.

Converter itself works with TV. How the Amiga's video output is different from the common set-top box (RGB with composite sync)?

Originally Posted by dJOS

I have one that does and it was only $50 on eBay.

Could you still find a direct eBay link to the same device?

[Stedy]

Originally Posted by ShK

Converter itself works with TV. How the Amiga's video output is different from the common set-top box (RGB with composite sync)?

Because the Amiga outputs 240p/288p video. This si fine in RGB, Y/C or Composite modes, all TVs can handle this. In YPbPr mode, 240p/288p is not a valid mode for the majority of TVs.

I have been developing a video adapter for a while now, 240p/288p in YPbPr is a problem still to fix, if it works, the SCUTA FPGA/CPLD will fix it. I tried bi-level and tri-level syncs on the YPbPr video I made from the Amiga, it made no difference. The lowest normal resolution for YPbPr is 480p (60Hz) and 576p (50Hz), that all analogue front ends are guaranteed to support.

Regards,

Ian

[Mr B]

Originally Posted by Stedy

Because the Amiga outputs 240p/288p video. This si fine in RGB, Y/C or Composite modes, all TVs can handle this.

Um... So why is it that not all TV's work with the scart RGB cables? They don't detect the RGB mode? I mean, i get nothing reliable from my LG, but both the PSX, and the XboX works with RGB cables. The PSX output goes nuts with NTSC, but PAL looks like the designer intended it to.

[dJOS]

Originally Posted by ShK

Converter itself works with TV. How the Amiga's video output is different from the common set-top box (RGB with composite sync)?

Could you still find a direct eBay link to the same device?

The video from the Amiga is not entirely standard RGBs composite sync (bi-level) and some devices and TV's dont like it (need tri-level sync) - this converter will do the RGBs-YUV video conversion @ 576i-PAL and 480i-NTSC without friging with the picture and trying to scale it etc:

http://www.ebay.com.au/itm/NEW-SCART...dfa167b&_uhb=1

I have one and it works great with most of my displays however I do have one Samsung 22" AV monitor that it doesnt work with - I've had very good results on my Pioneer 50" Plasma and Sony 32" LCD TV tho.

[dJOS]

Originally Posted by Mr B

Um... So why is it that not all TV's work with the scart RGB cables? They don't detect the RGB mode? I mean, i get nothing reliable from my LG, but both the PSX, and the XboX works with RGB cables. The PSX output goes nuts with NTSC, but PAL looks like the designer intended it to.

Typically only TV's with a European SCART connector have supported RGB, the rest of the planet has only ever had Composite, S-Video, Component-YUV and HDMI to connectors to choose from.

[Mr B]

That still doesn't explain why my LG doesn't work with the cable. I guess i worded my question poorly, TV's without the SCART clearly doesn't work with a SCART cable, but mine has a RGB SCART, works fine with everything else, and only flashes a frame of the Amiga every now and then over the SCART. Works with a mates Sony Bravia, even if the cable does ghost a little, but my LG 42LX650N is a dud...

[dJOS]

Originally Posted by Mr B

That still doesn't explain why my LG doesn't work with the cable. I guess i worded my question poorly, TV's without the SCART clearly doesn't work with a SCART cable, but mine has a RGB SCART, works fine with everything else, and only flashes a frame of the Amiga every now and then over the SCART. Works with a mates Sony Bravia, even if the cable does ghost a little, but my LG 42LX650N is a dud...

As explained earlier, Amiga's use a bi-level sync (instead of the more common tri-level) and some displays just can't understand it, my Samsung 22" AV Monitor is one of them but my Sony and Pioneer tv's work great.

[Solo761]

Originally Posted by Mr B

That still doesn't explain why my LG doesn't work with the cable. I guess i worded my question poorly, TV's without the SCART clearly doesn't work with a SCART cable, but mine has a RGB SCART, works fine with everything else, and only flashes a frame of the Amiga every now and then over the SCART. Works with a mates Sony Bravia, even if the cable does ghost a little, but my LG 42LX650N is a dud...

I also have LG LCD (42LW579S) and picture is no go. This is how it looks with [ Show youtube player ] and this is how it looks with [ Show youtube player ]. Tried the same cable on two CRTs and no problems there. It seems it simply the way LG works (or don't work in our case).

There is one odd thing that I noticed. In these sessions when I was experimenting and despaired I left my A1200 connected and turned on for 5-10 minutes. I noticed that sometimes parts of the picture come through

http://i.imgur.com/F0YoWCQ.jpg
http://i.imgur.com/bMeI3RK.jpg

[ShK]

Originally Posted by stedy

because the amiga outputs 240p/288p video. This si fine in rgb, y/c or composite modes, all tvs can handle this. In ypbpr mode, 240p/288p is not a valid mode for the majority of tvs.

Ok, this explains why the TV shows "the wrong signal format" -text.

Originally Posted by djos

the video from the amiga is not entirely standard rgbs composite sync (bi-level) and some devices and tv's dont like it (need tri-level sync)

Does the RGB to YUV component video converters do also the bi-sync to tri-sync conversion?

http://www.hiltonmediamanagement.com...bi-level-sync/

Originally Posted by djos

this converter will do the rgbs-yuv video conversion @ 576i-pal and 480i-ntsc without friging with the picture and trying to scale it etc:

http://www.ebay.com.au/itm/new-scart...dfa167b&_uhb=1

Thank you, I bought it!

Can you say if this SCART to HDMI converter can handle Amiga's 288p video too?

http://www.ebay.com/itm/400538432467

[dJOS]

The converter I linked to and own doesn't convert the bi-level sync to tri-level, it only converts RGB to YUV and my tv's display the video in 576i mode for PAL and 480i for NTSC.

So if your tv doesn't handle bi-level sync then you are out of luck. I have a 22" Samsung AV monitor that can't handle the signal but all my others work fine.

[Mr B]

Originally Posted by Solo761

I also have LG LCD (42LW579S) and picture is no go. This is how it looks with [ Show youtube player ] and this is how it looks with [ Show youtube player ].

Mine flashes a perfect fullscreen knifesharp frame. but it does so anywhere from once every five seconds, to once a minute.

I gave up, and grabbed a Indivision MKII. At this point i got image, and i'm sure a bit more tweaking will get me to near fullscreen, for most applications, so i can start saying "it works" but i quite frankly haven't been taking the time.

[ShK]

Originally Posted by dJOS

The converter I linked to and own doesn't convert the bi-level sync to tri-level

Is all the old set-top boxes tri-level synchronized, which these RGB converters are intended work for without bi-level to tri-level sync convert?

[ShK]

Here is an another RGB to Component Video Encoder:

http://www.jrok.com/hardware/RGBv4/index.html
http://gatorcade.com/rgbconverter.html

It needs negative Standard Resolution composite sync. But the FAQ says that it's not compatible with Medium Resolution video signals. Is the Medium Resolution same as 240p/288p?

http://www.jrok.com/hardware/RGB-FAQ.html

[ShK]

I made The Ultimate Amiga SCART Cable V1.1A. thanks Stedy schematics!



Moire caused by a mobile phone camera:

[dJOS]

So you upgraded your scart cable to Stedy's specs and that's it, your LG works with Amiga's now?

[ShK]

No scart problem with the TV. I'm trying to get that APTUS1 to work with the Amiga, but no luck. We'll see if that RGB to YUV Component Video Converter works, which I ordered on ebay.

[Stedy]

Originally Posted by Mr B

That still doesn't explain why my LG doesn't work with the cable. I guess i worded my question poorly, TV's without the SCART clearly doesn't work with a SCART cable, but mine has a RGB SCART, works fine with everything else, and only flashes a frame of the Amiga every now and then over the SCART. Works with a mates Sony Bravia, even if the cable does ghost a little, but my LG 42LX650N is a dud...

Is the cable made to my specification?

The most common problem, by far is the fact that the CSYNC signal is nearly 5X larger than the TV expects, hence the 330 resistor to reduce it to <1V. The Analog Front End in the TV works off 3.3V, expects 1V and you can feed it a 5V signal, not good.

Originally Posted by SHK

I made The Ultimate Amiga SCART Cable V1.1A. thanks Stedy schematics!

They've not failed yet. Did you try the cable without the optional AC coupling capacitors?

Originally Posted by SHK

Here is an another RGB to Component Video Encoder:

http://www.jrok.com/hardware/RGBv4/index.html
http://gatorcade.com/rgbconverter.html

It needs negative Standard Resolution composite sync. But the FAQ says that it's not compatible with Medium Resolution video signals. Is the Medium Resolution same as 240p/288p?

http://www.jrok.com/hardware/RGB-FAQ.html

The JROK is probably similar to this design, http://eab.abime.net/showthread.php?t=57512, which uses some op-amps to convert RGB to YUV and the AD724/AD725

The main problem with converting Amiga (and Atari) RGB or S/Video/Composite to YPbPr are the incorrect equalising pulses in the field blank period. For any mode but YPbPr, the TV can tolerate this but not this one. My technology demo board allows me to fiddle with syncs (bi/tri-level) and timings easily. I came to the conclusion I need to re-construct the V-sync timing for this mode to work and to hopefully also get HDMI online.

This is going off-topic now, will write this all up soon in my retro video guide.

Ian