How crappy of a TV do you need for composite video artifacts?

[MajorPainTheCactus]

Here’s my first stab at NTSC - to be fair this is basically NTSC-adaptive (something both @hunterK and @HyperspaceMadness have been saying to me to do for quite sometime!) fed into my shader with a few tweaks along the way but I’m learning stuff. I’ve not got the pronounced ringing either of the photos exhibit.

Let me know what you think?

EDIT: that’s something by the way I’ve taken the LCD photo above at 1/30 to get a more representative photo of what you see because of the two alternating phases. Maybe we could get another close up photo at 1/30 to see whether that ringing softens?

[sonkun]

I’d love to see what you come up with tweaking the NTSC Resolution Scaling and NTSC Blend Mode on 2 combo, according to guest it’s possible to come out with something nice but it’s tricky. I tried messing with it but just couldn’t come up with anything that I liked

[MajorPainTheCactus]

Hi Sonkun, so sure I could play around with them (in fact I did yesterday) but what exactly is the target youre after? More fringing? More accuracy to the above image? (If so what details in particular?) Something else?

[MajorPainTheCactus]

@Jamirus just to confirm the above photos are of your AEG CTV 4800 VT? One thing I noticed is the odd resolution scaling going on in both NTSC and PAL images - note pixel doubling in the black line of the hill. This is easy to simulate but I’m wondering where this is coming from in the original setup? Are you feeding an emulator output into the CRT for instance?

[sonkun]

Should’ve mentioned earlier but that combination is just for a sharper image. I couldn’t get it to look the way I wanted on my presets so I left the resolution scaling alone but kept the blend mode on 2 then just started sharpening in other ways. Curious to see what you could come up with if you’re interested in a sharper image

[Jamirus]

It’s still from the same emulator as before running on a Playstation 2 console. Some limitations are dictated by the hardware, others because of how things were developed. There are likely going to be differences to an original NES no matter what.

If you haven’t done it yet, check out that link I posted earlier in this thread (you weren’t around here then). This features grabs from various consoles, the Neo-Geo composite output is extra special bad: https://www.chrismcovell.com/gotRGB/rgb_compare.html

[Nesguy]

That looks VERY good.

We need some more reference shots with high-contrast edges (eg., black borders around sprites) as it’s the high-contrast edges that get blurred too much by most NTSC shaders IMO.

[MajorPainTheCactus]

Ah good to know we’re in the ball park of what’s expected! The one thing I’m really noticing is the very distinct ringing effect on the CRT. No matter what I’ve tried so far I can’t really reproduce that distinct dark then light ring around Mario say.

I’ve made the halo more pronounced and added a bit of deconvergence that I think the above CRT has - it’s probably a bit more accurate but still missing that particular ringing. I’m also wondering if that ringing is visible in person as much @Jamirus? (As in is it because we’ve captured one of two phases and in person you’d see both)

[MajorPainTheCactus]

Having read that article (thanks for the link!) I’m wondering whether using an emulator on a PS2 and then into a CRT is causing even more issues than we normally would by using the consoles directly. Hmm

[Jamirus]

It’s visible, I’ve turned down Sharpness down to zero now, and taken something with 60 sec and 30 sec shutter speed.

[MajorPainTheCactus]

Bingo! That makes sense it was the sharpening. I think we’re amazingly close now actually. What do you think? I mean with noisey images you’re never going to get it exactly right but that ringing is a lot more subtle and closer to the one produced in the shader.

The colours are off and I’m wondering why that might be - even in your images all the different options display different colours. The ones above are particularly red in the brickwork though.

[MajorPainTheCactus]

Here are my latest two images, top one 1/30 and the bottom one at 1/60.

Quite why mine are orange and the CRT ones are red I’m not sure. What is actually correct red or orange?

[Nesguy]

There is no correct when it comes to NES color palettes. I’d say the bottom is closer to what I consider “correct,” the bricks should be brown without an obvious red tint, IMO.

[Syh]

NES isn’t a system you want to use for color correction purposes imho. Like NESguy stated, there’s no real accuracy to be had with NES pallets.

So as long as you get the other things down, the color correction portion should be the easiest part I’d imagine, as we have a decent amount of documentation for NTSC color stuff.

[Jamirus]

Colour is a rabbit hole, you probably want to make sure the shader handles basic stuff like maybe dithering and such first. A better example than NES emulation is probably the PS1, the (fat) PS2 can play those games via it’s own hardware emulation. I had a look at the a menu of Street Fighter Alpha 3, because I just had that at on the USB disk I’m using along with Castlevania Chronicles and Final Fantasy Origins. Here’s a screenshot taken with PCSX-Rearmed:

Here is a part in RGB:

Here in composite:

[Syh]

I mean the main section of color is pretty straightforward imho, as NTSC has a color standard, as does PAL, if I’m not mistaken.

It’s when you get into how different hardware actually handled that, is where things get murky imo.

How different consoles output that signal, how different CRTs pull in that signal, how different CRTs actually process the signal before the electron gun fires.

[MajorPainTheCactus]

So when you say dithering what exactly are you talking about with regards to a CRT shader? I know what dithering is btw just trying to understand what part you think it plays.

[Syh]

I assume he’s referring to the Genesis primarily, which made heavy use of dithering for both “adding” colors and simulating transparencies, over “dirtier” signals.

[MajorPainTheCactus]

Yes but that’s in the original artwork though or is there some piece of hardware in the megadrive’s output circuitry doing things on top of the relatively standard NTSC/PAL conversion?

[Jamirus]

In a very general sense, I would expect a CRT shader with options of RGB and composite input to display dithering differently. There is such a thing as RGB dithering obviously, but I would for example expect a shader to be flexible enough to degrade the composite signal in such a way as to allow the blending of pixels for instance. Maybe, this isn’t quite as basic as I think, lol. To me this is like “this is a good reason you should actually use composite for this content”.