Different Sync technologies

[TheDrifter363]

Hello everyone,

I just recently purchased a xrgb mini, though it hasn't arrived yet, and I have a few questions about all these different sync technologies. So here is what i know:

(By the way, I live in the United States so I will be using NTSC consoles at all times)

All nintendo consoles, pre gamecube, have a dedicated csync on the av multiout. This csync is a dedicated sync pin that can be used with rgb that consoles like the snes and n64 are capable of.

Sync on composite video, as is used by scart standards, can introduce interference so its best to be avoided if possible. This can be avoided by using a dedicated sync pin, like csync, or using sync on luma (Y). The av multi out has both of these pins, however since the dedicated sync pin is there, might as well use that.

Now then, I bought two different rgb cables from retro console accessories for the snes and playstation. I will be talking about the snes for now. The cables are wired for japanese rgb 21, which is similar to scart but has a different pin out. I have verified this by using a multimeter to figure out what all the pins are connected to (or not connected to). This information was provided by these two websites:

http://www.gamesx.com/wiki/doku.php?id= ... ese_rgb-21

http://pinouts.ru/Game/n64video_pinout.shtml

The snes cable obtains its sync from compsite video. I have heard that this can cause interference and since the snes has the csync pin, I might as well take sync from that. I'm going to try to contact the woman that runs retro console accessories and ask her if it would be possible to change the sync pin. It should be a matter of desoldering the wire and changing the pin it connects to.

I also know that there are rgb n64 mods out there going up to cpu version 4. North American N64s began manufacturing at version 3, with version 4 being the most populous of the rgb capable mods. I have heard that the version 4 has its csync disconnected in some way. What does this mean? If it's disconnected, as in traces do not exist, can't I hook up a wire to reactivate csync? Though I have also read that other components were removed from version 4 that went along with the csync. So a simple wire would not be enough. I do not know the full details of re adding csync on version 4, but I believe one such method would disable composite video. I want to have that in the unlikely situation I would hook up the n64 with composite video, a backup. Also composite video sync causes a strange X shaped or some other anomaly on the n64 so its undesirable in any circumstance. Either obtain a version 3 or obtain a version 4 and find some way to restore csync without destroying composite video.

Then there is another option, an alternative to csync, this is sync on luma. What makes sync on luma different than sync on composite video? Both carry video data along with sync information, so wouldn't both be susceptible to interference? In the case of nintendo consoles, wouldn't it be better to use csync as it is a pin dedicated to sync and nothing else? That seems to be the case but I am willing to research alternatives as long as interference is minimized. If sync on luma would allow this, then it would be a viable alternative to sync on composite video. I do not know much about sync, so that is why these questions are being asked. As of right now, I see sync on luma and composite video as the same, video signals which carry sync information. Both in my mind have the potential for the same interference which is undesirable. Then again I must be missing some information, otherwise why would sync on luma be considered a viable alternative by others?

This follows into the second cable I bought, for the playstation. The playstation av multi out doesn't have a dedicated sync pin, so it must obtain sync from composite video. The cable I bought however, contains sync on luma, which according to the description is better as it doesn't contribute to interference. I've heard that there is also sync on green which is similar to sync on composite video, as it also contributes to interference. So both sync on green and sync on composite video are undesirable. This is the website where I obtained the playstation av pin out:

http://pinouts.ru/Game/PlayStationAV_pinout.shtml

I hope someone will be able to help me out and fill in the missing information about these sync signals. Why is sync on luma better than sync on composite video and sync on green? Wouldn't it also contribute to the same interference as the other two signals? Since nintendo consoles have a dedicated csync pin, then why not use that for all sync related endeavors? I thank you everyone in advance for any assistance you may be able to provide.

(In this whole post, I am referring to NTSC consoles and RGB. I know that scart uses sync on composite video as a standard and that european nintendo consoles are wired differently without a dedicated sync pin, like csync. The exception to this is the PAL Nintendo 64. I thought I should post this disclaimer once again.)

[Fudoh]

What makes sync on luma different than sync on composite video?

less interfering information. If luma is used the whole NTSC or PAL color subcarrier is already missing.

My advice: don't bother unless you have real visbile interference (more likely with PAL than NTSC systems) or if you have a processor or display that requires clean sync.

The only two systems where it makes sense to use clean sync right away are the MD/Genesis and the Neo Geo AES.

[Thomago]

more likely with PAL than NTSC systems

Is that because the PAL signal tends to introduce extra interference?

[spaceape]

Does it make any difference if you get pure sync directly from the console or clean up composite video sync later on in the chain using a sync stripper/sync strike?

[Fudoh]

@Thomago: don't know, I guess it has something do with the 4.43MHz of the PAL color carrier vs. 3.58Mh of the NTSC one.....

@spaceape: no, doesn't matter.

[TheDrifter363]

Ah that makes sense. So there's less interference with luma? From what I know luma carries black and white where as chroma would carry the color. Does chroma also carry all that other information like pal or ntsc?

So for my nintendo jp21 cables I'm going to get the sync replaced from composite video to csync. Mainly for consistency's sake and the fact that all nintendo consoles have that csync pin. I am curious though, I know on the sns-101, the super nintendo mini, you have to restore rgb as the traces are gone but do you also have to restore csync? Or is csync already active on the motherboard? The pin is there, but is it carrying a signal?

I still don't understand the n64 dilemna. For revision 4 why is csync missing? If so can't you just tap the origin of csync, which I think is the rgb encoder chip, and put a wire from that to the av multi out since the csync pin is already there?

[RGB32E]

I still don't understand the n64 dilemna. For revision 4 why is csync missing? If so can't you just tap the origin of csync, which I think is the rgb encoder chip, and put a wire from that to the av multi out since the csync pin is already there?

The traces on the rev 4 N64 PCB exist for CSYNC exist, but the parts to make proper CSYNC output are missing. The missing parts are identified with silk screen. As I understand it the CSYNC output from the encoder isn't suitable for direct use. Using luma for sync works fine for most configurations including the XRGB-mini. You can even bridge pins 3 and 7 on the multi AV out connector to feed luma to CSYNC if you're using RGB cables wired for CSYNC.

[BuckoA51]

Over in the Mini thread somewhere I did some comparisons of pure sync vs composite video for sync for the SNES and there was no discernible difference between the two. This isn't true on for XRGB3 in my experience but on the Mini it doesn't seem to make that big a difference.

[Nealist]

Hello there. I am new to this forum and this is my first forum post. I browsed the forum for some time looking for a discussion pertaining to my situation so as not to bog things down with a new and possibly redundant post. This topic seems most related to my situation.

I very recently got into upscaling and related technologies. I purchased a Silicon Image iScan Pro and a VGA to Component breakout cable to go with it. The iScan works great, however there seems to be an issue with the sync. I am using a PlayStation 2 with Component cables (which I use to play both PS2 and PS1 games thanks to the iScan) and there is a noticeable stutter with moving images. It is most noticeable on older side scrolling PlayStation 1 games (I tested Megaman 8 and Castlevania: Symphony of the Night.) The TV in question is a Westinghouse 46" LCD CW46T9FW. I am in the United States so all of my equipment is NTSC.

I am essentially looking for a plug and play solution to my stutter/sync problem. I'm not looking for the most accurate image, but rather the best working image that has no stutter or input lag. If I could find a device that doesn't need it's own power source that would be great as well. I see that there are a lot of different sync devices, but I am a bit overwhelmed by my options. I was hoping someone could point me in the right direction so I can find a device that best suits my needs. In the future I would like to get a scan line device as well, so any recommendations for an appropriate scan line device would also be appreciated.

[Sixfortyfive]

It probably goes without saying, but if you're getting cables wired for csync, make sure the csync pin on the AV port of your console is wired appropriately. Not everyone who mods N64s or SNES minis goes to that length unless you specify it.

Anyway, the only time I've personally seen this make a difference is on the NESRGB. You can see diagonal jailbars on the cvideo output. On the csync output, the colors are more uniform.

cvideo, cvideo w/ equalize filter
csync, csync w/ equalize filter

On the Genesis, I don't really notice a difference. I checked to see if there was any difference in jailbars between the two signals. My console is a model 1 VA6, which has considerably less distinct jailbars than earlier revisions in the first place:

cvideo, cvideo w/ equalize filter
csync, csync w/ equalize filter

[BuckoA51]

It makes a pretty big difference on the Genesis in my experience, have a look here:- http://www.videogameperfection.com/2014 ... ve-stereo/

Particularly on the second screenshot with the colour bleed test see how the csync cable performs so much better.

While it's not as important as it was with the XRGB3, from what we've been seeing lately in the Mini thread, it seems clean sync is often desirable there too. I'd say if you were going for new cables for a XRGB Mini and you can easily get clean sync, go for it. If you already have composite video for sync cables and they perform well, don't worry about it as clean sync isn't likely to make any difference.

XRGB3 users should ALWAYS use clean sync cables wherever possible. In my experience using clean sync IS better than using a sync stripper too (at least where XRGB3 is concerned).

[Fudoh]

@Nealist: you emailed me before, didn't you ?

Iirc the stutter isn't caused by the iScan. The iScan's output is framelocked to it's input, so it's more likely that your TV's input just doesn't like the exact refresh rate with which you're games are being output. On the iScan you got the choice between component and RGBHV output, so you can try both on your TV (if available). You also also convert both to HDMI (component is to be prefered) and give that a try.

[Nealist]

@Fudoh: Yes, I did email you before.

I've used both the VGA and VGA to Component cable with the iScan. I feel that the image is better with the VGA to Component. I will try converting the Component to HDMI and see if that helps. Would I be looking for an actual converter box or just a set of cables?

Thanks to all for the help and information. I'm excited about reviving my old games.

[Fudoh]

yes, you need a converter and not just cables. The one you linked to should be fine.

Still weird that you get judder through the iScan with component. It's *exactly* the same refresh rate as the PS2 delivers without the iScan (just 31khz instead of 15khz).

[nyder]

yes, you need a converter and not just cables. The one you linked to should be fine.

Still weird that you get judder through the iScan with component. It's *exactly* the same refresh rate as the PS2 delivers without the iScan (just 31khz instead of 15khz).

Sorry to jump in with this but I've been struggling with some sync issuues.

I have both composite sync cables for my SNES and Genesis 1. They both make my PVM-20l5 judder.

Is it possible my 20l5 wants clean sync not composite sync? the l5 likes my ps2 and saturn rgb scart cables just fine, no judder.

I get the same judder when I use the Hanzo VGA box on my l5, but not when I use my old blaze vga box.

This is drivin me nuts

Thanks,

Nyd

[Nealist]

I got the HDMI converter box and did some more playing around with my hardware and these are the results I've found.

I decided to unplug all my video peripherals and plug my PlayStation 2 directly into my TV with my aftermarket component cable. The resolution is 480i/60Hz. What I noticed is a slight "hiccup" as well as a sort of shaky or noisy image, both of which are barely noticeable when you're paying attention to the game. My current component cable replaced a different after market component cable on account of there being strange white horizontal lines that seemed to flicker in place, which I don't recall being there when I first bought the cable. I found the noisy component cable to be far less annoying than the horizontal lines component cable when all was said and done. I have not tried using my older cable in any of these scenarios, though I suspect the same, if not worse results.

When I run my PlayStation 2 through the upscaler the noisy image is removed, but there is significant screen tearing rather than the slight "hiccup." The upscaler output to 480p/60Hz.

When I run the video to the converter box, the converter box outputs to 480i/60Hz. The noise is removed, and while there is no screen tearing, there is still the slight "hiccup." There is also a dark brown or red tint that appears in place of true black or white and there are dark brown/red bars on either side of the displayed image. I didn't mind how that affected the rest of the color palette as the colors looked richer and warmer, but it was annoying not to see black or white when I should have been seeing black or white.

When I run the video to the upscaler and then to the converter box the noise is removed and the output is 480p/60Hz. There is still the same issues with the "hiccup" and with the dark brown/red tint and the bars on the side.

This suggests to me that there is something fundamentally incompatible with my TV, my aftermarket component cables, or both.

[Fudoh]

I really can't tell. Most likely it's the TV.

Do you have any means to give the PS2/iScan combo a try on a different display - just to verify that everything's fine there ? The iScan's output is always 100% tearing-free, so your TV doesn't like the refresh rate at all.

[Nealist]

My next course of action would be to test things on another TV, though the ones I have access too are much smaller. Other than that perhaps the previous owner of the iscan changed some sync jumpers on the processing board, but I'm sure that would have resulted in a corrupted image or none at all.

[panzeroceania]

Does anyone have a setup with a ps1 or ps2 using separate hsync and vsync signals to a monitor that supports it. I don't yet but was looking into it and was wondering if there is anything I should keep in mind.