NTSC shaders redux

[sonkun]

@Cyber So after looking around a bit I came to find some info on how composite works on different systems, it seems nes and snes composite pretty much works the same, we both know how Genesis works from my composite presets. I read that pc engine didn’t do checkerboard dithering, not sure how true that is as I can’t find any reliable images of real hardware hooked up to a crt and then the last one I need is sega master system which I also can’t find any good pics of using real hardware.

I already put together presets for nes, snes and genesis that’s ready to go in a new update, I just need to know how pc engine and sms composite works, so if you have any pics of those two systems showing off rainbow banding/color artifacting please do share lol

[guest.r]

As a general reference you can search for 2-phase or 3-phase signal coding/decoding. And maybe for fields merging.

[sonkun]

I’ll give that a go. Maybe I should search for psx, saturn and n64 pics as well even though I’ve never seen or played those systems through composite at all.

If nothing else I’ll just use your ntsc shader and load up those systems and eyeball mimic the color banding and call it a day

[Nesguy]

@guest.r do you remember what color palette was used in the shot you posted recently? That may be the missing ingredient.

[guest.r]

It should be Sony CXA…i compared it with the screenie. I also cranked up the contrast to get more intensive artifacting, remember now.

[Cyber]

@sonkun

I read that pc engine didn’t do checkerboard dithering

Many PC Engine games employ all sorts of dithering. Not sure if they would have appeared transparent or fully blended over a composite input like the Sega Genesis though because the output was clean and many times high res. The PC Engine used high res modes a lot in games compared to the Sega Genesis and SNES.

So in many cases you might just see the dither patterns depending on the screen used, input I guess (I only used composite) and viewing distance. It wouldn’t appear as harsh as in DOS games on a VGA/SVGA monitor though because we’re using composite on a TV/Commodore Monitor but dithering was very common as far as I know on the PC-Engine/TurboGrafx-16/Turbo Duo.

My latest shader preset and video filter combination blends a lot of the dithering without sacrificing the resolution and sharpness though. This can be seen in the blue gradient behind Esty in the Gate Of Thunder intro and in other areas and games as well.

You’ll still see the dither patterns in other areas of the intro like on Hawk’s gloved index finger.

But you can’t go around using the same levels of de-dithering/softening/NTSCing for PC Engine as you do with Sega Genesis. Things like text will quickly begin to appear unbecoming of the Turbo, while the Genesis will tend to be much more forgiving.

@sonkun

off rainbow banding/color artifacting

I can’t remember ever seeing rainbow banding on a PC Engine (TurboGrafx-16/Turbo Duo) game in real life. I can’t even remember seeing it on Sega Genesis but those memories would be even more faded than my TurboGrafx-16/Turbo Duo ones. Maybe I just didn’t notice the rainbow effect on Genesis

As for PC Engine, I remember how clean it was on my Commodore 1702. That mask pattern was beautiful on such a small, high quality screen.

Checkerboard-Dedither shader

Here is one from the Lords of thunder level [Lords of Thunder (USA)-220902-165431]

Some more examples of dithering on the PC-Engine:

John Madden Duo CD Football - PC Engine Super CD-ROM² (MiSTer FPGA)

John Madden Duo CD Football (TurboGrafx CD) Playthrough - NintendoComplete

John Madden Duo CD Football Review for the TurboDuo

Some videos showing PC-Engine Games running on CRT Displays:

r/retrogaming - New CRT, makes such a huge difference with PC Engine games!

Very useful and important information about how the PC Engine produces its colours:

PC Engine palette improvements - the amazing people behind the technology

This is also a good Resource if you would like to browse the PCE Library and see which games use dithering:

http://www.pcengine.co.uk/HTML_A-Z_Pages/A.htm

Many of the posts have gameplay and longplay videos.

http://www.pcengine.co.uk/HTML_Games/Addams_Family.htm

Misc. Turbo Stuff that I found interesting:

PC ENGINE / TG16 - Awesome Imagery from turboxray PCE

Seeing some slight rainbow artifacts/fringing going on on some edges of pixels here, especially on top right right edges of round shapes or shapes with diagonal edges particularly during right to left scrolling.

Video uploaded said he just has the composite out of the Turbo Duo hooked up to the capture card.

MEGA MAN CD - TURBOGRAFX 16 / PC ENGINE

[Fab]

This one should be useful.

Regarding composite, PC Engine has the same problems Genesis has. Not that terrible, but it’s the same phase, so image quality and colours both get a blow.

[Cyber]

@Fab

PC Engine has the same problems Genesis has.

I think to suggest that the PC Engine has the same problems the Genesis has might be a bit of an oversimplification which can lead to misunderstanding.

I think that the Genesis has some problems and characteristics of its own which are unique to it and not present on the PC Engine.

If it were a case of sameness as described in your post then the two machines wouldn’t have such vast differences in Composite video quality.

The article even talks about the colourburst averaging which improves image quality.

NES

“These don’t look so bad in composite, thanks in a large part to the colour burst averaging that happens between successive frames on the NES/Famicom/SFC/PCE. Still, colours become faded and much less distinct.”

NEC PC-Engine

"We can see that the PCE’s output is pretty good as far as bold colour fidelity goes. Many of the shots below display very fine details in RGB that are even carried over in composite. The major noticeable difference, however, is the different colour balancing and component weighting which is a function of the PCE VCE’s composite encoder.

Well, enough praise. With Daimakaimura, we can see that the 320-pixel mode of the PCE produces more blurring and NTSC artifacts which degrade the image quality somewhat. Also, there’s still some unavoidable loss of colour definition in composite. For example, did you notice that in the Doraemon pic Nobita-kun has a bleeding knuckle? It’s very hard to notice this with the PCE’s composite."

Sega Master System

“Sega’s 8-bit system is pretty notorious for its poor video quality. It smudges horizontal details all to hell, and introduces colour fringing and rainbows even in areas that contain only black & white!”

SNK Neo Geo

“Anyway, the NG’s composite video is just horrible. It’s a bit dark and muddy, even greyscale graphics get significantly blurred, and there’s a horrible checkerboard interference pattern around strong colours.”

Sega Mega Drive

“The Mega Drive gets its own page because of its notoriously bad composite video. Once I set up my digitizing equipment and took snapshots of a few games, I just got carried away and took pics of many of my favourite games. Or, I took pics of especially egregious examples of just how much the MD muddles, blurs, and confounds the composite video display to the dismay of its hapless users.”

Excerpts taken from article below.

https://www.chrismcovell.com/gotRGB/rgb_compare2.html

Your post has me slightly confused.

Are you sure you don’t mean the Genesis, Sega Master System and Neo Geo suffer from the same problems? What problems are you referring to in particular?

[Fab]

" we can see that the 320-pixel mode of the PCE produces more blurring and NTSC artifacts which degrade the image quality somewhat. Also, there’s still some unavoidable loss of colour definition in composite"

Exactly this. It’s phase 2 NTSC, the same of Genesis, and it has that kind of problem. Saturn has that problem, too, same resolution. For example the same doesn’t occur (at least not with the same result) on SNES, which is phase 3 NTSC, as it has a 256 pixel output.

But there’s a catch. On PC Engine games used a variety of resolutions, and it’s undocumented which used what (like, you don’t have a list). Some say only a few used 320px, others say the majority of the library used something higher than 256, Wikipedia says most used exactly 256, so who knows.

In my experience the issue stated above is something I’ve noticed when playing PC Engine games, as I noticed it on Genesis and Saturn, and that’s why I use Sonkun’s presets on those platforms, as MAME NTSC is “agnostic”, while guest’s NSTC use the exact phase. I should check if it depends on some setting in the emu, though, maybe it forces a 320 pixel output (but I don’t tink so).

[hunterk]

Most PCE games are 256 width, but indeed some use other resolutions, but they also sometimes switch resolution mid-frame. For example, there’s some ultima-style RPG that draws the top of the screen at 256 and the bottom text area at 320(?). On a real CRT, this doesn’t matter, but it’s very difficult for us to deal with properly.

[Cyber]

@Fab

Some say only a few used 320px, others say the majority of the library used something higher than 256, Wikipedia says most used exactly 256, so who knows.

https://pcengine.proboards.com/thread/84/why-pce-games-horizontal-rare

[sonkun]

I went through all replies here, @Cyber thank you for the video links. I ended up going by what @guest.r said up above and measured these systems by the “phase” system. I went and loaded up all the main old systems even the unpopular ones then loaded up guest’s ntsc shader since it chooses the correct ntsc phase per system automatically with that adaptive ntsc shader added in and this is the list I came up:

Systems that use 2phase ntsc:

Atari 5200, Atari 7800, Atari Jaguar, Sega Megadrive, Nintendo 64, Neo Geo CD, NEC PC Engine/CD/Super Grafx, Panasonic 3DO, Philips CDi, Sony PlayStation, Sega Saturn.

Systems that use 3phase ntsc:

Atari 2600, Nintendo, Sega Master System, Super Nintendo.

My composite preset is pretty much a hybrid mix of a phase 2 ntsc shader that gives you phase 2 ntsc rainbow effects with the vibrant colors you get from phase 3 ntsc instead of the washed out colors you authentically get from phase 2 but without the correct rainbow effects you get from phase 3.

So with all that information my preset covers all the phase 2 based systems as far as rainbow banding goes, however I don’t get the same authentic rainbow banding for those 4 systems above I mentioned that use phase 3 ntsc like we see in the Ninja Gaiden pics above (my composite presets doesn’t produce those thin diagonal rainbow effects).

Now my next question I need to ask myself is it worth going out of the way to re arrange my whole preset pack to add in a “phase 3” composite preset for just 4 systems that have different rainbow effects? Perhaps. And that’s where I’m at so far in this conversation. Decisions decisions lol.

@Fab the good (or bad depending on how look at it) thing about that mame ntsc shader is that it allows you to make that same authentic washed out look you get from a phase 2 ntsc signal but who wants washed out colors? I guess that’s where I drew the line of trying to look too “authentic” that’s why my presets ended up looking the way they look.

[Cyber]

@sonkun

same authentic washed out look

I don’t think authentic means a player would have had a washed out experience by using composite or even a blurry experience. TV’s had sharpening circuitry and besides that things just ended up being sharper on a CRT TV than on our modern displays using shaders. filters and upscalers (as @Nesguy has been so painstakingly demonstrated to us).

TVs also had colour, picture, sharpness, brightness, contrast and tint controls.

I would think that if a user found their games to be looking washed out that they would just turn up the colour and adjust the brightness.

I doubt many if any of us had colorimeters or professional calibration software or even knew what calibration was in the 80s and 90s. Yet we seem to have some who are obsessed with perfect colour accuracy today. I find that a bit strange.

[sonkun]

I should’ve clarified in my last post, I meant authentic as far as ntsc phase 2 looks in the adaptive shader default settings. I know you can tweak the ntsc settings in that shader but that wasn’t my point. I don’t have a crt or real hardware to go off of so I’m kind of forced to reference pics/videos online and ntsc shaders available on RetroArch. That adaptive ntsc shader seems to be the best one available so I used that as my main source in my last post.

[Cyber]

@sonkun

I meant authentic as far as ntsc phase 2 looks in the adaptive shader default settings

I understood this. My comments were just a generalization based on my observation of the state of things over the past couple of years. Not really directed at you in particular. I just used your comment as a point of reference.

[Jamirus]

If you read this guide, the implication is that composite on the Genesis / Megadrive can be quite different depending on the model.

https://www.sega-16.com/forum/showthread.php?7796-GUIDE-Telling-apart-good-Genesis-1s-and-Genesis-2s-from-bad-ones

Using the 32x will also alter the composite output completely, because it converts from RGB. These kind of differences are probably not uncommon across hardware and signals, e.g. SNES 1 Chip vs 2 Chip RGB.

[Cyber]

This is good ol’ Blargg NTSC Composite from the Nestopia Core Options plus one of my latest CRT Shader Presets. I wish I could tweak those Blargg settings in the Core Options.

[sonkun]

You should try out the “Composite” shader pass from the “crtsim” shader, I gutted that pass out of that shader and made my new “composite ntsc 3-phase” shader preset with that that’s in my latest shader pack. Came out pretty nice and it has a good number of settings you can tweak, looks very similar to the Blargg filter here you should check it out.

[Cyber]

@sonkun

You should try out the “Composite” shader pass from the “crtsim” shader,

@sonkun

I gutted that pass out of that shader

Wow! More stuff to learn…lol. I’ve never strung together different shaders before. I’m sure I can learn how to it if necessary though. My time to do this is quite limited though so I’m not sure when I’ll be able to try it out.

I originally returned to these forums looking for a replacement bezel, shaders and shader presets for the Analog Shader Pack 3.0. I found them all in the same place with HSM Mega Bezel Reflection Shader, I really don’t want to play without those amazing reflective bezels anymore.

Maybe someday, I’ll experiment and explore other shaders.

Is this CRTSIM shader different from the MAME shader that you combined with CRT-Guest-Advanced-HD?

If so, why did you choose it over the MAME shader?

[sonkun]

Yeah I learned tricks like that from the user Syh (@Syh where the hell you dissapeared to man?? You’re missing out on all these new upgraded shaders here), he also taught me about the greatness of the grade shader too so I guess he’s kind of the reason for me even forming these presets.

@Cyber

Is this CRTSIM shader different from the MAME shader that you combined with CRT-Guest-Advance-HD?

Yeah it’s kind of different as far as customization, it does an amazing 3-phase ntsc output, I didn’t tweak it to try and make a 2-phase ntsc output so I don’t know how it does in that area though.

@Cyber

If so, why did you choose it over the MAME shader?

Good question. Quite simply because the mame ntsc wasn’t giving me satisfying results no matter which way I tweaked it. There’s a setting on the old mame ntsc version called “Signal Offset” which when it’s turned on it seems to just blend everything perfectly with a little jitter added in, it works perfect for recreating the 2-phase signal but when I turned that setting off to try and make a 3-phase signal it changes the whole picture in a way where pixels look somewhat distorted at least to me.

So I ended up ditching that and went looking at every other ntsc shader available to merge into my preset, I tried them all and just wasn’t hitting that sweet spot and then I stumbled upon that composite pass by random that was used in a whole different shader. I traced the original location of that pass back to the crtsim shader then I proceeded to perform my operation and here we are lol.