Removing RGB jail bars idea?

[Drakon]

You are bypassing it for Composite and S-Video. And if you're Genesis has a CXA1645 (Like many late Model 2s) you will see no improvement at all from using the 32X as that's the same encoder the 32X uses.

You are so wrong it hurts. The 32x doesn't use a cxa1645. Here's the encoder found in the 32x:



cxa1645 pinout:



notice how the cxa1645 has 24 pins but the 32x encoder has 32 pins...

Also the fact that the 32x encoder is wired completely different from how you would wire a cxa1645.

The rgb that comes out of the cxa1145 is not "bypassing" the cxa1145.

My genesis 3 consoles that use the built in cxa1645 have jailbars in the s-video picture. I've bypassed the cxa1145 in my model 1 with a cxa1645, even a cxa2075, and they all get the jailbars. The jailbars come from the vdp chip.

[TrekkiesUnite118]

My bad on that one. My point still stands though. The 32X isn't filtering anything, it's just using it's own video encoder which just happens to be better than the one in your Genesis. If it was truly filtering the video signal we'd see it in the RGB signal, but we don't. It just has a better video encoder in it, that's all.

[Drakon]

My bad on that one. My point still stands though. The 32X isn't filtering anything, it's just using it's own video encoder which just happens to be better than the one in your Genesis.

Yes I agree the video encoder in the 32x is wicked. It's too bad it's a custom made chip that you can't buy, but it is acting as a filter. The video distortion is coming right out of the vdp in the genesis. Something in the 32x, either the encoder or the video circuit, is filtering out the jailbars in s-video. The jailbars don't disappear from "better encoding". Better encoding a rgb picture that's full of vertical bars will just give you a sharper image with crystal clear bars! If you ever s-video mod a genesis 3 you'll see what I mean, It's a nice clear picture with bars! I don't quite know enough about video circuits to determine what's fixing the s-video in the 32x but I'm glad that a fix exists that's better than my system of branching off 12 feet of video cable. And the 32x is filtering, it's just doing the filtering at the s-video level but not at the rgb level if you still get bars in rgb.

For rgb users....try installing a rgb + sync splitter and attach it to 12-20 feet of branching off cable that plugs into nothing and see if that helps. It's a ghetto filter that fixes bars and other distortion in both s-video as well as rgb that's being fed into an encoder. So I don't see why it wouldn't also work with just straight rgb.

[Genesis Knight]

I say bad RGB cable in such a case.

What RGB cables do you use? You don't have any jailbars on yours?

[Drakon]

Here I drew a quick diagram of my jailbar fix.



rgb users everywhere give this a try! If this helps....great! If it doesn't work....not big loss.

Unless you just have your rgb cable wired wrong like tiido suggests.

[TrekkiesUnite118]

Yes I agree the video encoder in the 32x is wicked. It's too bad it's a custom made chip that you can't buy, but it is acting as a filter. The video distortion is coming right out of the vdp in the genesis. Something in the 32x, either the encoder or the video circuit, is filtering out the jailbars in s-video. The jailbars don't disappear from "better encoding". Better encoding a rgb picture that's full of vertical bars will just give you a sharper image with crystal clear bars! If you ever s-video mod a genesis 3 you'll see what I mean, It's a nice clear picture with bars! I don't quite know enough about video circuits to determine what's fixing the s-video in the 32x but I'm glad that a fix exists that's better than my system of branching off 12 feet of video cable. And the 32x is filtering, it's just doing the filtering at the s-video level but not at the rgb level if you still get bars in rgb.

For rgb users....try installing a rgb + sync splitter and attach it to 12-20 feet of branching off cable that plugs into nothing and see if that helps. It's a ghetto filter that fixes bars and other distortion in both s-video as well as rgb that's being fed into an encoder. So I don't see why it wouldn't also work with just straight rgb.

The 32X doesn't do any kind of image manipulation that could possibly be considered image filtering when playing a Genesis game. The Genesis RGB Signal comes in, and it gets sent straight out to the 32X video encoder. So it's the way the 32X is encoding S-Video that does this, not any kind of filtering system. Considering the shots Ace showed of his Genesis using a different encoder to get Component Out didn't appear to have any Jail bars it doesn't seem that crazy to think a better video encoder could remove that problem.

[Drakon]

*sigh* something tells me we're both talking about the same thing just using different terms. Something in the process of encoding the rgb into s-video is filtering out the jailbars. I'm pretty sure a cxa2075 isn't a terrible encoder but it gets jailbars too. Anytime the jailbars disappear they're being filtered out. The jailbars are present in the source of the image which is the vdp, so you're not actually getting rid of jailbars you're filtering them away with a hardware filter. Removing the problem would be having a vdp / ppu that outputs rgb without the jailbars....like what a super nintendo does. If people are getting jailbars on their rgb tvs I think it's safe to say that the jailbars are present in the source of the image and any removal of these jailbars is them being somehow filtered away.

[TrekkiesUnite118]

It's entirely possible. The point is the 32X doesn't filter anything, it just does a better job encoding video than the Genesis does. For example my VA0 Model 2 has horrible vertical bars, through composite, but the 32X encoder doesn't have this issue and gives a very clean and sharp looking picture in composite. It's not filtering out those vertical bars, it's just doing a better job encoding the image.

EDIT: Here's a question, do 32X games have Jailbars when played through RGB? Or is it only Genesis games?

[Drakon]

like I said it's just different terms technically the 32x doing a better job encoding is acting as a filter. I managed to re-create the effect of this "better encoding" by adding 12 feet of s-video cable branching off from my cxa2075 s-video output. I could literally plug in / unplug the s-video cord and watch the jailbars go away and come back on my tv. I wasn't using a "better video encoder" I was just plugging in / unplugging my really ghetto video filter. For all we know there could be something in the 32x circuit that's filtering out the jailbars it might not even be the encoder.

*edit* here's some screenshots to demonstrate.

S-video from my cxa2075 circuit straight into the capture device:



S-video from the same ca2075 circuit with 12 feet of s-video cable branching off and connecting to nothing:



These two screenshots were taken from the same system with the same video encoder circuit. The fix of these jailbars is not by "better encoding" it's because I made some sort of a filter. I'm not saying that the 32x encoder itself isn't doing the filtering it's very possible that's where the image gets filtered. But whatever fixes the jailbars in the 32x is working like a filter. If I can re-create the fix using 12 feet of s-video cable and a splitter then obviously the fix isn't because you're using a "better encoder". You're probably just using a circuit that's better tuned for encoding the mess we know as sega genesis rgb.

Regarding your question about 32x games I don't know I'm still waiting for my mega everdrive to show up

[TrekkiesUnite118]

Or it could be by splitting it off like that you are weakening the signal or something along those lines. Plus you're filtered shot doesn't seem to be as clear as the unfiltered shot. It looks like by splitting the video signal like you did you weakened it just enough to slightly blur out the vertical lines. You can still see them faintly in your filtered shot.

[TmEE]

What RGB cables do you use? You don't have any jailbars on yours?

That's my cable:


you tell me if you see any jailbars (don't confuse with moiré):
http://www.fileden.com/files/2008/4/...Scanlines2.jpg
http://www.fileden.com/files/2008/4/...Scanlines1.jpg
http://www.fileden.com/files/2008/4/...Scanlines0.jpg
http://www.fileden.com/files/2008/4/...5/RGBSCART.jpg
http://www.fileden.com/files/2008/4/...elyRGBshot.jpg
http://www.fileden.com/files/2008/4/.../RistarRGB.jpg
http://www.fileden.com/files/2008/4/...Sonic3RGB0.jpg
http://www.fileden.com/files/2008/4/...Sonic3RGB1.jpg


Regarding 32X :

RGB from MD is over/underlaid with RGB from 32X, and then output and also transcoded into s-vid and composhit. RGB from MD is buffered by CXA or equivalent and it might induce crosstalk and such.

@Drakon : that long wire is as sood as a capacitor to ground on the signal. Except capacitor is more effective. What it would do is smudge up video signal in the composhit line and the jailbars along with it, and your TV is then extracting the slightly distorted but still recognizable sync info and you get image. Too much filtering and the sync info is too smudged up too.

[Genesis Knight]

Crap! You would have a custom cable; I was hoping you would have one I could just buy.

Edit: http://www.fileden.com/files/2008/4/...Sonic3RGB0.jpg

This one looks like it has jailbars in the whitespace between the two save files?

[TrekkiesUnite118]

I think that has to do with the way the shot is taken of the TV. If you follow those lines you see they curve and bend towards the top. There's no jailbars in any other parts of the shot like there are in the other shots posted of this issue.

[TmEE]

That is moiré there, jailbars do not bend around.

My cable is nothing but a good SHIELDED cable with RGB and composhit signal + 5V for RGB switch (the lone wire).

[TrekkiesUnite118]

So if I understand this correctly the Jailbars come from the Composite sync signal?