Any chance for composite blend like in Genesis?

[Threepwood]

I wondered if the amazing composite blend feature of the Mega Drive / Genesis core can be added to other cores?

The Master System is among my fave systems (and it was too empty in here), thus I will raise the question here for the Master System.

[darksakul]

Does the Sega Master System use Dithering?

[Threepwood]

Does the Sega Master System use Dithering?

I could not find info that says that it does, so I doubt it. Is the composite blend (not adaptive) option in the OSD using features that are exclusive to the architecture of the Genesis?

[mic_]

Does the Sega Master System use Dithering?

Maybe not as prominently as on the Mega Drive, but there are several games that use dithering to varying degrees. For example Ghostbusters, Golden Axe Warrior, Legend of Illusion, The Smurfs, and probably many others.

[Moondandy]

Bob from retrorgb did say he was hoping this could be added to the MS core.

[Sigismond0]

Bob's a great guy and I give him mad props for all the great stuff he does for the community. But him hoping someone can add a feature to a core is absolutely no indication of whether or not it's possible.

If we're just talking full composite blending and not adaptive, then the answer is most likely yes. That's just applied across the whole picture, and shouldn't be complicated to port to other cores. I don't think it uses any genesis-specific hardware features, but I could be wrong there.

Adaptive blending is a whole different thing though. There was a thread on the old forum showing some issues with the adaptive blending not working "correctly" on some games. Turns out, adaptive only works with dithered foreground transparency elements, and not dithering on all layers. There was one game that did its shadows with a combination of dithered background tiles and foreground tiles, and the result was awful--some tiles had the blending effect applied, and some didn't. Because of this, I strongly doubt it would be possible to port over directly to the SMS in any meaningful way.

[SegaSnatcher]

I can't imagine SMS would benefit from it as much as Genesis.

[Threepwood]

I can't imagine SMS would benefit from it as much as Genesis.

From what I understand it blends pixels into each other and gives the image a look of old composite video output. It looks beautifully CRT so why would any core not benefit (or benefit less) from it? I guess because of the color palette?

EDIT: Cleaned up misunderstanding

[SegaSnatcher]

I can't imagine SMS would benefit from it as much as Genesis.

From what I understand it blends pixels into each other and gives the image a look of old composite video output. It looks beautifully CRT so why would any core not benefit (or benefit less) from it? I guess because of the color palette?

EDIT: Cleaned up misunderstanding

Well the reason it was specifically added to Genesis was for dithering effect. Transparent Waterfall effect in Sonic 1 for example.

https://www.youtube.com/watch?v=x0weL5XDpPs

[Threepwood]

Well the reason it was specifically added to Genesis was for dithering effect. Transparent Waterfall effect in Sonic 1 for example.

https://www.youtube.com/watch?v=x0weL5XDpPs

Understandable, but if the composite blend feature recreates this loss in color information, then all systems would benefit from it in regard to an authentic old look. I agree that some would benefit more than others depending on how heavily this was exploited when creating the art for the games, but back then basically everything was created for home TV and not BVM/PVM Monitors. Composite blend would give us a more authentic old image display.

I would love to have this option in SMS and other cores, because it looks much more like the image we had on standard TV sets.

I don't have time to read it all in detail now, but I got the impression that this makes a good case for it:

https://nerdlypleasures.blogspot.com/20 ... osite.html

https://nerdlypleasures.blogspot.com/20 ... ourri.html (See the warehouses in the background of the video at the bottom)

Maybe Sorgelig and the devs can shine a light on this.

[LeftEmpty]

Oh I thought that option was in the Mega Drive core only for CRTs, and that HDMI could rely on the various effects/filters to achieve a similar result. That's not the case?

[Threepwood]

Oh I thought that option was in the Mega Drive core only for CRTs, and that HDMI could rely on the various effects/filters to achieve a similar result. That's not the case?

Not at all. You especially need that option on LCDs otherwise games that rely on dithering through composite blend look wrong and can be unplayable.

There is no filter that comes even remotely close to this option and that includes some ominous Comp_Blend_HV-filters some youtubers use. I tried them and it is just a blur filter that even in the max blur version does not work well and looks quite bad (thus it should not be called "Comp_Blend" to begin with).

Same for the Master System and surely for the SNES and all other systems that were used with CRTs. Look at this link, please: https://nerdlypleasures.blogspot.com/20 ... ourri.html

At the bottom of the article you have a screenshot of a warehouse in Shinobi on the Master System, which is made up of magenta and black lines. In the video below you can see how it looks on real hardware and how it is supposed to look.

Here a collage with the footage from that source:

SMS_RGBvsComposite_NerdlyPleasures.png (145.74 KiB) Viewed 55684 times

[LeftEmpty]

I shall test this someday when I plug my MiSTer in hdmi again. I'm very excited to see how it renders now!
I'm a big supporter of blurry options: my favourite console, the PC-Engine, may be beautiful in RGB, but the Japanese games made heavy use of the r-f/composite blur for their Japanese font and make it easy on the eye.

[Threepwood]

I shall test this someday when I plug my MiSTer in hdmi again. I'm very excited to see how it renders now!
I'm a big supporter of blurry options: my favourite console, the PC-Engine, may be beautiful in RGB, but the Japanese games made heavy use of the r-f/composite blur for their Japanese font and make it easy on the eye.

It currently is only available in the Gensis core, though. That is why I ask if it can be added to the other cores.

[Kitrinx]

The cofi module I wrote is very portable, at least it was when I wrote it, however the value outside of the genesis core is very limited. For HDMI you can simply use the composite video filters by Soltan that do the same, Genesis dither was just SO bad that for some games the video was virtually broken without it. So even rgb/component CRTs needed this filter to look ok.

[Threepwood]

The cofi module I wrote is very portable, at least it was when I wrote it, however the value outside of the genesis core is very limited. For HDMI you can simply use the composite video filters by Soltan that do the same, Genesis dither was just SO bad that for some games the video was virtually broken without it. So even rgb/component CRTs needed this filter to look ok.

Where can these filters be downloaded and what are they named? I tried, but could not find them.

I have a pack of "composite blend" filters that a youtuber uploaded. They go by the name scheme of "Comp_Blend_HV_050.txt", but these do not work as well as your module. Even when using a "Comp_Blend_H_100.txt" it does not fully blend rows of pixels as it is supposed to be. Your module does that well and gives the screen a nice CRT look. However if there are other filters, I will gladly try them, but they are not downloaded via updater and I could not find them online.

In general my go to filter is "Catmull-Rom_Scanlines_010.txt" and on the Genesis I prefer to combine Composite Blend ON with it.

I would argue that the dithering effect caused by composite blend was used on all consoles to some extend, like transparency in speech boxes of rpgs on the SNEs or the warehouses in Shinobi on the Master System. I am not refering to the adaptive blend, but only to the "On"-settings.

Thanks for explaining why it was added in the first place, that is interesting to know

[vanfanel]

Master System needs the same blending as the Genesis core, I totally agree.
The TOTAL, un-selective blending that the Genesis core does is just INCREDIBLE, perfect, absolutely delicious. Games just look as intended, at long last. It has been what, decades? since I saw a Genesis game properly displayed. And thanks to that "simple" option, there it is on my HDMI screen, Genesis games looking as they were designed to look like. Most games are designed to look "blended", not only water in Sonic or lights in Streets of Rage 2: Look at Chakan, Comix Zone, Greendog, Castle of Illusion, Eternal Champions, Earhworm Jim, Tiny Toons, Lion King, Aladdin... Most of the Genesis library is designed with composite blending in mind. Those I mentioned are OBVIOUSLY using blending to get new colors, effects, etc.

Well, for the Master System its exactly the same.

To the person who was smart enough to add the un-selective, complete composite blending to the Genesis core: THANK YOU.

I have been trying for years now that something like this is implemented on the MegaSG, but of couse, no one will listen. This single option has shown me that open, public projects are always better, and to stay away from future closed-source FPGA products.

[darksakul]

I have been trying for years now that something like this is implemented on the MegaSG, but of couse, no one will listen. This single option has shown me that open, public projects are always better, and to stay away from future closed-source FPGA products.

That is an apples to oranges comparison and each project has to weigh the pros and cons of adding such a feature based on the needs and capabilities of that project.

The issue is not so much if the project is public or private (closed or open sourced) but on the individual developer and if they find such changes feasible on their current projects and workload and factoring the hardware limitations as well. That is assuming they even want to add such a change. Because of the legal nature of things Analogue can't just lift the code used by the MiSTer for composite blend, they have to write their own in a clean room approach from scratch. And the other is if you change one thing in the code does it break the rest of the code or not.

Also paraphrasing what Sorgelig said in another unrelated thread
Individual devs do what they want. Redargless if the project public or private.

[Threepwood]

@Kitrinx What filters were you suggesting earlier to get composite blend?

It would still be great if the composite blend option from the Mega Drive core could become a default feature of the framework to be used in all cores as I found no filter yet that works remotely as well as Kitrinx' "Composite Blend ON" feature.

[Kitrinx]

@Kitrinx What filters were you suggesting earlier to get composite blend?

It would still be great if the composite blend option from the Mega Drive core could become a default feature of the framework to be used in all cores as I found no filter yet that works remotely as well as Kitrinx' "Composite Blend ON" feature.

It seems Soltan never uploaded them to the repo. I have a set of composite blending filters on my local card. Maybe he will in the future.

[vanfanel]

@kitrinx: are they .txt filters? Maybe just upload them here for now? I would love to have Master System with your unselective composite blending! It must look fantastic.

[Threepwood]

@kitrinx: are they .txt filters? Maybe just upload them here for now? I would love to have Master System with your unselective composite blending! It must look fantastic.

I have a feeling it is the same set of filter files I got from this youtube video: https://www.youtube.com/watch?v=3wHSI3JbnlY (see the mega-link in the description).

The feature baked into the Genesis Core is much better, though and thus these filters are no substitute.

[Chris23235]

Thanks for the link, I really like composite HV25%, it looks great.

[Threepwood]

Thanks for the link, I really like composite HV25%, it looks great.

These filters hardly do anything except for making the image blurry. They do not result in the composite blending effect.

Let's take a look at Sonic 2 on Genesis (right click on the screenshots and open them in a new tab to see them full size, please).

Here a screenshot without Filter and no Composite Blend:

Sonic-2_No-Filter_No-Composite_Blend.png (1.12 MiB) Viewed 55439 times

In Contrast here with Composite Blend ON:

Sonic-2_No-Filter_Composite_Blend_on.png (1.32 MiB) Viewed 55439 times

This is how it is supposed to look.

To compare here without Composite Blend and with the filter "Comp_Blend_HV_025":

Sonic-2_Comp-Blend-HV25.png (1.15 MiB) Viewed 55439 times

It only makes the image somewhat blurry, but does not cause the intended blending that composite would cause. Even with "Comp_Blend_HV_075" it does not look as intended and just gets very blurry:

Sonic-2_Comp-Blend-HV75_No-Composite_Blend.png.png (1.48 MiB) Viewed 55439 times

These filters are just blur filters that do not achieve a composite blend effect. They are no substitute for what the Composite Blend ON feature does.

[Chris23235]

Doesn't change the fact, the HV25% looks great in my opinion.

[FaSMaN]

Hi guys

I know that I am fairly new here but composite blend was one of the biggest hesitations I had with the mister , as I know that it really makes a difference in some games, for instance the Wolfenstein 3D Megadrive homebrew leans heavily on it due to the way it renders walls and limited resolution.

After giving the mister a shot so I tried the Composite blend on the genesis and it absolutely blew me away, does the correct blending and smoothens out the walls properly on Wolf3d , I wanted to try this on other cores but it seems this feature isnt included so I registered here to check and tracked down Comp blend some thing something HV filters from some dodgy YT videos and I am not impressed its a standard blur no proper blending (no calculations).

If this feature can be ported to other cores it would be great especially for the demoscene that really programmed their demos to utilize composite.

So just for clarification here are some screenshots.

Filter Off Composite Blend enabled:

Filter_OFF_Composite_Blend_ON.png (703.57 KiB) Viewed 54687 times

HV 100

H_100.png (949.89 KiB) Viewed 54687 times

HV 75

HV_75.png (842.91 KiB) Viewed 54687 times

HV 25

HV_25.png (734.74 KiB) Viewed 54687 times

[msimplay]

Hi guys

I know that I am fairly new here but composite blend was one of the biggest hesitations I had with the mister , as I know that it really makes a difference in some games, for instance the Wolfenstein 3D Megadrive homebrew leans heavily on it due to the way it renders walls and limited resolution.

After giving the mister a shot so I tried the Composite blend on the genesis and it absolutely blew me away, does the correct blending and smoothens out the walls properly on Wolf3d , I wanted to try this on other cores but it seems this feature isnt included so I registered here to check and tracked down Comp blend some thing something HV filters from some dodgy YT videos and I am not impressed its a standard blur no proper blending (no calculations).

If this feature can be ported to other cores it would be great especially for the demoscene that really programmed their demos to utilize composite.

I feel the same way to be honest the filter should be available in all cores IMO.

Every console has used dithering in some way all the way upto the PS1/Sega Saturn.
I always connect my classic consoles via composite and I go out of my way to do so.
It was the biggest hurdle for me buying a MiSTer setup I am even now looking for a good way to connect via composite to a CRT.

Sega extensively used dithering even in the Arcade

I know the PS1 is not supported yet but see the fog in Silent Hill through composite vs s-video it looks smooth and foggy unlike through s-video

https://youtu.be/4tq0DKz4FrQ

The PS2 and above really benefit from RGB

[Sorgelig]

While talking how good one particular scene when screen is heavily blurred you completely disregard that wast majority of time it simply render the video as complete crap without any benefits.

[Threepwood]

While talking how good one particular scene when screen is heavily blurred you completely disregard that wast majority of time it simply render the video as complete crap without any benefits.

"Crap" is subjective. Nobody disregards that proper composite simulation degrades the image quality. It was this degraded color information that was used to achieve certain effects, like blending, in-between colors, fake transparency etc. That Wolfenstein 3D homebrew posted earlier would basically be unplayable without it.

Kitrinx' Composite Blend option looks much better and leaves the image sharper than these fake Comp Blend filters that really only blur the image and do not achieve the actual blending effect of composite.

MiSTer is the only system doing this composite blending properly, at least in the Genesis core, and it is one more feature that makes it stand apart from the rest. You already have voices here of people who prefere composite. Some want RGB perfect quality, some more original quality with composite and since Kitrinx said the module was initially made to be very portable, why not include that option in all the other cores of systems that were used with a CRT?

MiSTer is awesome and more display options won't hurt it. On the contrary, with the Composite Blend ON feature it has an option to represent the games as they were intended (they were made for standard TV sets and not PVMs or BVMs) on market available hardware. This does not only have the benefit of recreating a more original image quality with all the tricks used, but it greatly adds to MiSTer as a teaching and preservation tool, too.

We are not pointing out a flaw in MiSTer here, we are applauding you and the devs for having such a feature implemented. All we ask for is: Can we please have this option in the other cores, too, so we can choose for ourselves?

[Sorgelig]

No idea about which improvement you are talking about. If you force enable composite blend when it applied on full screen, the same Sonic looks very bad. I never used it till adaptive blend was added. Even if sonic gets some benefit from blending in very particular screens, it's not worths to enable it if it cannot detect the places where it has to be applied.

Wolf3D is originally very pixelated game. Talking about dithering on some walls in this game is meaningless. If you wouldn't show that pic i wouldn't even notice.