TG16/PCE/Duo Composite, S-Video, Component Comparison shots

[tomaitheous]

There was a Sega-16 thread that compared 32x composite output to the Genesis native composite output (same Genesis game). The 32x has its own composite encoder and does give the image more saturation to color than the original Genesis composite output (a little too much IMO, but you can just turn that down a bit in the TV settings). It's not just capture cards.

For capture cards, if I think if they get the Luma channel wrong (the scale from black to white, on the encoder itself - not software), it can drastically effect the chroma decoding. All my Genesis hook ups to my capture card have seriously hot and blown out saturation (actually, the luma scale of the bright colors). Chris Covell's captures look surprising good.

I noticed that particularly with your Megadrive shots that the reds turned yellow or orange in most of the shots. I have found with several capture cards that this is caused not by the composite output but the deinterlacing method used. Basically the more frames/lines are lost in the deinterlacing process, the more reds change is all I have noticed so far.

Technically, that shouldn't be (sounds more like post processing in the capture software). There's no alternating phase shift of the CB and chroma channel per line or per frame, on the Genesis. There's no chroma dot pattern either (alternating like the PCE or fixed like the SNES). Just a straight vertical mask exactly at 7.159mhz (it's what causes the unique edge transition artifacts on saturated colors). The line mask doesn't alternate from frame to frame either. I.e. there's nothing changing from frame to frame to give a build-up/temporal (30hz) difference.

electrochip: I have another request (if I'm not pushing my luck ). It's a bit of the strange request, but it involves showing how the new composite/s-video chip outputs the chroma dot pattern. Can you put the composite output of the new chip, into the Green component input of your nice TV? Then take a screen shot? Something that has both gray or desaturated pixels and also large saturated colored areas (the more saturated the better). If you can't find anything, that same place in MM3 would work. Don't worry that what's on screen will be black and white, that's perfectly fine.

Edit:

Chris, nice shot comparison Hey, that dot pattern on the Neo Geo color transition edges. Is that 60hz XOR alternating on a real SDTV?

[ccovell]

All my Genesis hook ups to my capture card have seriously hot and blown out saturation (actually, the luma scale of the bright colors). Chris Covell's captures look surprising good.

Hey, that dot pattern on the Neo Geo color transition edges. Is that 60hz XOR alternating on a real SDTV?

The dot pattern doesn't move at all on the Neo-Geo, so it's as ugly as can be for static images.

Yeah, I did notice the capture card captured reds as orange. The MD's just a bit too hot, I guess. I calibrated levels with the PCE using the colour bars cheat in Thunder Blade, and on the MD using Sword of Vermillion's CRT test. The hot oranges only became normal reds after I had turned the brightness so far down on my capture box that white became a dark grey.

I guess that's what NTSC encoding does. Whites and pastels seem to have a lower maximum brightness in composite than saturated reds, greens, etc.

[tomaitheous]

Thanks for the info Chris

Also, this:

The was some noise in the video signal (it's about a 20 foot cable with an open splice), so I had to run a noise filter on it - which is why it isn't as clear as it could be (added a tiny/slight vertical blur). But it's pretty clear as is. That's composite output of the original PCE.

I found a utility for BT 8x8 chipsets. BT tweaker which you can use with virtualdub. You can disable the notch filter, which allows you to keep the resolution of Luma in PCE mid res captures (which is normally filtered down as it's a multiple of the chroma signal frequency).

PCE has a 60hz XOR dot pattern (perfect checker board, unlike the NES/SNES) on the Luma channel only for chroma pixels, going down the screen. The dot pattern is twice the chroma signal frequency (3.579mhz), regardless of the resolution. It inverts this pattern every frame. So colored pixels get a resolution boost when viewed at 30hz. None moving pixels and pixels that move at or less than 30hz will retain this res (Blazing Lazers first level scrolling BG layer for example). My shot above just accumulates two frames since I can't show 60hz blinking stuff here. You might think it would be flickery on a real set, but remember the human eye is less responsive to both resolution and temporal changes of red and blue.

[sheath]

The dot pattern doesn't move at all on the Neo-Geo, so it's as ugly as can be for static images.

Yeah, I did notice the capture card captured reds as orange. The MD's just a bit too hot, I guess. I calibrated levels with the PCE using the colour bars cheat in Thunder Blade, and on the MD using Sword of Vermillion's CRT test. The hot oranges only became normal reds after I had turned the brightness so far down on my capture box that white became a dark grey.

I guess that's what NTSC encoding does. Whites and pastels seem to have a lower maximum brightness in composite than saturated reds, greens, etc.

I tried adjusting the color-tint-brightness setting of video captures for a long time. For my televisions I use an older A/V DVD to set the video settings perfectly for my rooms and I wanted to duplicate this for video captures. I eventually settled on leaving it at default because of the wide variety of PC monitor types that were out there at the time.

Now that virtually everybody seems to be using LCD I'm tempted to make some minor adjustments again. But then I am noticing that Laptop users all keep their monitors at different angles, which affects colors and brightness.

I'm pretty sure that Sega-16 thread about the differences between Genesis and 32X outputs was using my screenshots of SFII SCE, Revenge of Shinobi, and Shinobi III over my old Ati AiW 7500.

Actually, I was just telling Tom, my new HVR 6500 perfectly doubles the color saturation when the 32X is hooked up. I had to use Dscaler to get the color saturation down to 64 (from 128) to get the color back to normal. The last four galleries on GP's front page are from the new card, the Ninja Spirit and SFII Turbo shots are at 128 default saturation.

-edit-

I just uploaded screenshots for my Christmas gift, Splatterhouse for TG16. Here are a few choice ones that seem to have oddities:

[tomaitheous]

Here's something:


(larger view here: http://www.pcedev.net/pics/composite...are1_large.png)

RGB in emulation shots, not only makes the colors darker - but the color relative to other colors themselves, is different. Look at the above sky. In the RGB one, you can't even see the third (middle) blue color for the sky gradient.

electrochip: how does your component converter handle this fight scene back drop?

The above right pic might be a bit light (I tried to calibrate it by eye to one of my SD sets), but even if you darken it - you can still see the middle sky color. I.e. it's not a direct effect of lightness or darkness of the over all image:

[sheath]

RGB in emulation shots, not only make the colors darker - but the color relative to other colors themselves, it different. Look at the above sky. In the RGB one, you can't even see the third (middle) blue color for the sky gradient.

I can see the middle blue gradient in both shots on my laptop LCD, but they are different shades. If I angle my monitor towards me the shot of the left (emulation?) loses the middle blue. Otherwise there are three layers of blue visible on my screen in all three shots.

[tomaitheous]

I can see the middle blue gradient in both shots on my laptop LCD, but they are different shades. If I angle my monitor towards me the shot of the left (emulation?) loses the middle blue. Otherwise there are three layers of blue visible on my screen in all three shots.

Hmm, might be the gamma correction on your LCD monitor. What about this shot? http://www.pcedev.net/pics/composite...gb_lighter.png or a bigger shot: http://www.pcedev.net/pics/composite...ter_larger.png

I mean, it's there - but it should be ever so slight of a difference in the original left shot (from the top sky blue to the middle sky blue).

Edit: I can tilt my LCD 60 degrees either way (up/down) and there really isn't any noticeable difference (there's a tiny bit when I tilt it down about 60 degrees - everything is darker and so I can see it a tiny bit more).

[sheath]

Hmm, might be the gamma correction on your LCD monitor. What about this shot? http://www.pcedev.net/pics/composite...gb_lighter.png

I mean, it's there - but it should be ever so slight of a difference in the original left shot (from the top sky blue to the middle sky blue).

That shot is very hard to see the middle blue. It is only visible when my monitor is at a very odd angle. The other ones are very distinct on this screen. It's a nice LCD though, you can see the screen clearly from 80 degrees on either side.

[tomaitheous]

Ahh, ok. (I updated my post too)

Yeah, just sounds like a gamma thing (a non linear scale of RGB values). It usually has a bend to the scale near the bottom (which that color is only 1 step in RGB pce values from the one above it on the blue channel)

[electrochip]

I sold the Duo-R I had with the S-Video mod, I'll be putting another together soon though. As for the screenshot of the RPG through component, what game is it?

[tomaitheous]

The Startling Odyssey 2 (there's an english translation patch too). The very first area has that battle background.

[killersquirel]

Is there any plans or schematics that are online to do the s-video/component mod for the turboduo?

Thanks,
Mike

[electrochip]

The best I can point you to is this link http://www.pcenginefx.com/forums/index.php?topic=2788.0

I didn't use it, I have made the circuit for other systems and applied it to the PCE's.

[tomaitheous]

electrochip: Actually, I have the perfect test tool; Chris Covell's 512 color demo. I hacked it to run off CD instead of rom (sorry Chris, it was easier than modifying the source code). The download link is here: http://www.pcedev.net/pics/composite.../512colors.zip . That would be a huge help.

[electrochip]

finally got things in order and uploaded the screen shot test, and will have updates for the colors demo in component.

[sheath]

I keep forgetting to do this, too much drama going on in the real world. Anyway, here are the shots I took from Covell's Screen Test. I wasn't really clear on what we were looking for, so I just took shots of each of the horizontal resolution modes from my DUO/R.







-edit-

These are taken straight from the Win TV software from my capture card. My usual method is to use FRAPS to capture from the MPEG video capture using maximum settings. Please let me know if this is what you were looking for.