Discussion on the VGA to Composite/S-Video Adapter from RetroCastle

[momo]

I purchased this and have been using it on and off for about a week. You can find it here.

I haven't found any other information about it other than the tiny review on the product page.

Comparing Super Mario World on my real SNES with a good quality S-video output and the mister with the VGA adapter's S-video output, the adapter looks a little blown out in comparison to the real thing. There's a clear delineation between the scanlines in solid red graphics on the SNES, but the VGA adapter seems to have some bleed or looks a little blown out in comparison. I can still see the scanlines, so I wouldn't call it bad at all, but it's definitely brighter/blown out in comparison to the SNES.

I still need to do some comparisons with the composite, but the VGA adapter will output both composite and S-video at the same time. Comparing both outputs on the adapter, the composite output looks basically the same in quality except that there's a weird shimmering/wavy effect around edges or certain bright colors like red which I don't think should be there. There's also a lot of rainbowing. There's a potentiometer on the adapter that can be adjusted (very carefully) to reduce or eliminate the shimmering, but the rainbowing doesn't seem to ever go away despite some reduction. I decided to stick with S-video because of this for now.

I still need to do comparisons between the composite from the VGA adapter and composite from a really good source, like maybe the 32X playing a Genesis game or an SNES composite cable if I can find one. I've been enticed by @CRTPixels on Twitter comparing composite to RGB.

As far as actually playing with S-video, I will say that I like it more overall than component on my CRT. It does smooth out the graphics. It's like the difference between pixel art and drawings, though it seems like it could be taken further with a better adapter. I'm still not sure about that, as I've alluded to.

If anyone else has experience with this adapter and others or comparisons with the real thing, I'd like to know.

[MikeS1]

I might be a bit bias, but I do have some experience with this exact chip used in RetroCastles design. Its pretty much identical to my board I built back in 2021 https://github.com/MikeS11/MiSTerCRT. It uses an AD724 NTSC/PAL Encoder, and has a trim capacitor to vary the input clock to help reduce the dot crawl affect on composite.

Your question is a bit loaded as well, if you're talking about composite and real hardware, you can really only compare those that actually had it built into the hardware. E.g. NES/SNES/Genesis. Any of the Arcade cores, the Neogeo MVS, will all have problems with artifacts, especially with red. And if you look at something like the NES, it has a very unique way of encoding its signal and doesn't use encoders like the CXA1645 you would see on other consoles, so that would have to be built into the FPGA as well.

The main reason I dropped that design and moved into using the FPGA to encoder YC was because of the dot crawl problems I had with both S-Video and Composite using the AD724. But back to that design, its flawed for a couple of reasons, the first being it doesn't actually have a built in luma trap so the rainbowing is always going to be a problem, second its dot crawl can be adjusted with the trim capacitor but it has limitations, is annoying to change each core, and is also prone to failure in the future. I think the encoders are built to be a bit blown out for colors as well but I have not really compared them directly.

[momo]

Very interesting, thanks for the info. I'm pretty new to this and wasn't aware of encoders or the unique ways different systems output composite video. In that way, it sounds like it's a better idea to use the YC cores and have a dumb cable/output board. I purchased the RetroCastle board partly to get the effect I wanted, but also thinking that I would probably be going with a different solution in the future.

[siskavard]

I just got this very same adapter in the mail today. I'm curious how you got it to work, what ini settings, etc.? All I'm getting is a flickery blue/pink screen.

I"ve messed with a few ini settings but I can't find any combination of settings that seem to work for composite. Haven't tested S-Video yet.

Thanks,
Corey

[Longtime4321]

You have to set the jumper on the IO board. I believe it's right below the vga port.

[siskavard]

Thanks I got it working!

[lotsotech]

Any ideas why is be getting black and white only out of the retrocastle? Composite works fine but on svideo there's no color. The SOG toggle doesn't do much (basically toggles between working and inconsistent sync). I tried a variety of video settings in the INI, but not really sure what to look for. Wondering if it's a bad board, but hoping it's just something easy.

[Allejo]

In my experience, the quality won't be that good because it's a passive Y/C adapter, I have the passive Y/C adapters from Retrocastle and UltimateMister and the image quality from both of them is iffy (it's not the manufacturer's fault, it's just that passive adapters seem to be inferior than active adapters).

To get a good image quality from composite and s-video you should get an active Y/C adapter. I have the active adapters from Misteraddons and Retrocastle and the image quality is great (and there's no difference in quality between the two imo). The links for them are: https://pt.aliexpress.com/item/1005005267629034.html and https://misteraddons.com/collections/mi ... oder-board

Btw, (shameless self-promotion here lol), but if you ever decide to buy the active adapter from Retrocastle, I just released for free a 3D printable case for it, so you won't have to have an exposed circuit board lying on your shelf https://www.printables.com/model/701951 ... etrocastle