Removing RGB jail bars idea?

[TrekkiesUnite118]

You don't even know if there are jailbars in rgb for one thing. The s-video is being generated from the rgb. If disconnecting the subcarrier trace kept interference from "leaking into the rgb" you would see the different in the s-video as well. You just don't get the concept of how it works, which is fine I'm done trying to explain things. If you've got some great fix for some interference that you don't even know even exists, please go ahead and do it.

I understand how RGB gets turned into S-Video. What you seem to be failing to grasp here is that S-Video is different from RGB. For one the subcarrier is used for S-Video to get the Chrominance signal. If you disconnect the Subcarrier you're going to screw up your chrominance output for S-Video. If you disconnected the Subcarrier to get rid of the Jailbars you wouldn't be able to see a difference in S-Video because you wouldn't have any S-Video at all. Lifting the subcarrier might work for RGB, but it probably won't work for S-Video as you need to use it eventually to get S-Video. If the Subcarrier is the source of the jailbars you really can't get rid of it in S-Video as it's required as part of the encoding process. What you can do for S-Video is change the circuit or video encoder for better results that tend to filter it out, which is what you have done. However theres still residual artifacts that remain from the Jailbars which I can see in all of your shots. So as TmEE said many pages ago you aren't really filtering them out, you're just smudging them.

[lumclaw]

I do know there are jailbars in rgb. I've personally witnessed the effect, due to having recreated it entirely on my own using two separate consoles / games / RGB cables, and provided photographic evidence to support my claim.

(Minor fix for clarity.)

[omp]

Here are some pics I took from my TV RGB to component converter vs composite. I won't comment, simply upload some shitty pics.

RGB to component


composite


The text looks cut off as I had the TV on wide-full, on normal it gets the bars on the side since it is a widescreen TV.

Again not looking to argue about anything, just putting these up.

[omp]

For troll-alol-alol SMS2 (modded with RGB etc) Probably not the best, but rough idea?
RGB to component


composite

[MEGADRIVE Jeroi]

Yeah the rgb-component is ideal. Very nice image on those pictures.

[Drakon]

You can get rid of the subcarrier in s-video by driving the encoder using a crystal oscillator that's separate from the genesis. We've mentioned this many times already. I'm not "smudging" anything my screenshtos demonstrate that picture has perfect sharpness.

All these above screenshots look jailbar free. But nobody wants to listen to me....so whatever keep believing that there's jailbars in rgb and thinking that there's no possibility that you just have it wired wrong.

I've been telling people just to wait for me to get a rgb to component encoder which I already ordered. I plan on wiring it up properly to see if these jailbars even exist. And if there are jailbars I can take a look at what can be done about them. But instead of running around quoting everything I read on the internet like it's THE BIBLE I'm actually buying the hardware and testing / tinkering with things myself.

[TrekkiesUnite118]

The issue here though is that you are acting like your S-Video mod is the fix when it's not. The Jailbar issues are actually quite different here which is what you are not getting. Your S-Video jailbar issue shows up on everything, the RGB jailbars only show up in the blues. If the S-Video Jailbar issue truly came from the same RGB jailbar issue we'd see jailbars in all colors in RGB just like we do in S-Video. But we don't. This is what leads me to believe the issues are not completely related and the RGB one is interference. In S-Video all the colors get combined into one signal and they all have the subcarrier applied to them. So assuming the subcarrier is the source here it makes sense that all colors in S-video have the jailbar effect. What you've shown here is that better encoders (32X) can filter it out as can you with your own fix. I'm not quoting internet ramblings as though they are the Bible, I am simply pointing to evidence that backs up the claim that RGB has Jailbars in the blue signal and it comes from the Subcarrier.

If I had the time and equipment to test it myself I would. But I don't. That doesn't mean I can't look at the evidence and come up with an idea.

@omp, can you show a shot of the Genesis that has a more solid blue color, like a shot of the Sonic 1 or Sonic 2 title screen? From what I've seen that's where the jailbars are easiest to see.

[Drakon]

"the rgb jailbars only show up on blue" you don't even have a rgb setup you're just quoting that stupid thread from assemblergames. You just go around believing everything you read on forums. A number of people have said that there's no jailbars at all on rgb yet you refuse to believe this. I keep telling you to wait for my component encoder to show up since I'm the only person who actually buys hardware and tests things around here. I can "come up with ideas" all day based on stuff I read on forums but until you actually try something you never know.

[TrekkiesUnite118]

I'm not blindly believing everything I read on forums, I will however accept photographic evidence as fact that the issue does exist. I never said that I refuse to believe that there are no jail bars on RGB. I am simply saying that if after lumclaw gets a chance to check his RGB cables finds that the problem still persists, that it could be from the subcarrier.

[lumclaw]

"the rgb jailbars only show up on blue" you don't even have a rgb setup you're just quoting that stupid thread from assemblergames. You just go around believing everything you read on forums. A number of people have said that there's no jailbars at all on rgb yet you refuse to believe this. I keep telling you to wait for my component encoder to show up since I'm the only person who actually buys hardware and tests things around here. I can "come up with ideas" all day based on stuff I read on forums but until you actually try something you never know.

It's worth a try. Let's just not take the results too literally at first glance. rgb to component encoding may or may not be necessarily be indicative of the problem's severity. Such a conversion could filter down jailbars.

We haven't proven ALL models/revisions of Master System or Genesis are affected anyway. It could very well be minor tweaks by Sega impacted this issue. Don't forget I've never heard about jailbars on the PAL model Mega Drive 2. What I own is Genesis 2.

[Drakon]

As I've said many times just wait for my component encoder to show up....oh f#ck it this's getting retarded I'm going to wire up my jrok and see if the component video from it works.

[lumclaw]

Um. This is a serious issue, it'd take crippling eyesight problems to discredit. Normal people can't simply not notice jailbars to the severity in my upper photo.

[Drakon]

Um. This is a serious issue, it'd take crippling eyesight problems to discredit. Normal people can't simply not notice jailbars to the severity in my upper photo.

Where's your upper photo?

Anyway I wired up my jrok component converter. First I tried wiring it straight into the vdp but that didn't work because it needed to be amped. So I wired it into the av out pins after the rgb gets amped by the cxa1145.







It's a spare genesis I use for testing stuff. Anyway the results....uhm.....EXTREMELY weak jailbars. The jailbars were so weak my camera doesn't even pick them up at point blank range. And the jailbars are not just in blue they're in red, blue and green. I'd say they're about as strong as the jailbars from my revised cxa1145 s-video mod...if not weaker. I next lifted pin 50 from the vdp and the extremely weak jailbars went *poof*. Well....that was an easy fix....for something that was barely there to begin with. I'd love to see the jailbars that lumclaw and anonymouse are getting because even without pin 50 of the vdp lifted they were kind of hard to notice. Why lifting the subcarrier from the pcb works I don't know...I should have tried lifting it from the cxa1145 first but I was lazy and it was easier to get at pin 50 of the vdp.

I also noticed there seems to be no rainbow banding but I expected that. I'm 99% certain rainbow banding is caused by the subcarrier line. When I drive s-video encoders off of a crystal oscillator the rainbow banding disappears. The fix for s-video might be something as simple as driving the cxa1145 off of a crystal where you can adjust the frequency until it matches the timing of the system.

So lifting the subcarrier pin of the vdp does work credit goes to whoever came up with that idea. Unfortunately if you're not so great at soldering lifting pin 50 could be very difficult....more difficult than doing my 32x s-video mod. I bridged a bunch of vdp pins together but I have techniques to clean that up so fixing it didn't take very long.

[lumclaw]

Where's your upper photo?

My earlier post. Top photo is from a Master System. Bottom photo is from a Genesis 2 with 32X connected. Entirely separate game, console, and cable. Same encoder and TV.

This is using an LCD so jailbars are more noticeable. AFAIK by nature of how CRTs operate, they should be extremely weak on most CRT sets. Though I can't confirm this since I only own one CRT with component input.

http://www.sega-16.com/forum/showthr...l=1#post492974

[Drakon]

well lumclaw try lifting vdp pin 50 I did notice a difference. But it's very easy to bridge the pins on the vdp just to warn you. And it can be difficult un-bridging those tiny pins if you spend all your time posting on forums but never actually doing any mods like some people. Lift vdp pin 50 and lose the ability to have s-video....and fix up your rgb cable.....and that's really all I can think of.