Looking for a good comb filter

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orange808
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Re: Looking for a good comb filter

Post by orange808 »

austin532 wrote:I guess what I had imagined in my mind was something already pre-built that you just plug in RGB/Component in one end and output clean composite out the other.
The Timeharvest Supergun also accepts RGB input and outputs composite or svideo. Those units are preassembled in a nice case with a normal power supply. I think that's what you want. Plug in SCART cable, plug in a composite cable, flip the SCART IN/OUT switch to "IN", and power it on.

I briefly tried the feature out. I didn't spend much time with it, but the results were fine.

It's also a pretty good little supergun.
Last edited by orange808 on Sat Sep 07, 2019 2:39 pm, edited 1 time in total.
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FinalBaton
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Re: Looking for a good comb filter

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andykara2003 wrote: I’m wondering - I’ll use the console on a couple of my consumer CRTs - a Sony trinitron (good UK made set pre 1997).

Is it likely that a decent external comb filter would far surpass the ones in even these higher end consumer sets resulting in a much better composite image?
In my experience, the comb filters in Sony sets are pretty good - provided that there's one to fucking begin with (I say that because the PVM-2030/2530 doesn't have one - only a notch filter - and I thought the stock NES looked absolutely horrid on that set)

especially on later sets the, composite picture for games looked pretty clean I thought. I had an a later early 2000s FD Wega and the NES looked pretty damn clean on it. On my 1986 Sony XBR, the NES's dot crawl and it's shimmering can't be hidden as well without blurry the image with a low sharpness setting, but other composite sources look fantastic on it (I have a Gamecube plugged through composite on it and it looks nice). The color handling of that set for composite is pretty good.

I think what will dictate what kinda picture you get, is whether there's a 3-line liter or a digital 3-D filter in yours
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austin532
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Re: Looking for a good comb filter

Post by austin532 »

I feel like it goes both ways. Most games from that era benefit from composite blending and give that authentic and intended look but their are some non dithering games that do look better in RGB and reveal much more detail that you normally wouldn't see.

I am aware that comb filters tend to soften the image but the big trade off is a much cleaner signal.
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andykara2003
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Re: Looking for a good comb filter

Post by andykara2003 »

nmalinoski wrote:I think the main desire to use composite over RGB is because there were a number of games that relied on a combination of dithering and how the composite video encoding process treated that dithering to cause color blending and transparency effects. There's a writeup with screenshots of this effect as it relates to HD Retrovision's future HDMIzer product on RetroRGB.
Sure, the Megadrive uses lots of dithering - I'm not sure if I'm that bothered though. That unit looks amazing. Shame there'll be no version with analogue 480p out for CRTs.
Taiyaki wrote:I think S-video still turns out better personally.
I'll experiment with that, thanks :)
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Re: Looking for a good comb filter

Post by nmalinoski »

andykara2003 wrote:
nmalinoski wrote:I think the main desire to use composite over RGB is because there were a number of games that relied on a combination of dithering and how the composite video encoding process treated that dithering to cause color blending and transparency effects. There's a writeup with screenshots of this effect as it relates to HD Retrovision's future HDMIzer product on RetroRGB.
Sure, the Megadrive uses lots of dithering - I'm not sure if I'm that bothered though. That unit looks amazing. Shame there'll be no version with analogue 480p out for CRTs.
There won't? Where did you hear/read that?
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orange808
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Re: Looking for a good comb filter

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I'll put it this way. The ideas for HDMIzer are *very* ambitious.
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Guspaz
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Re: Looking for a good comb filter

Post by Guspaz »

They really aren't overly ambitious in terms of what they intend to support. The only question will be if they can deliver it at a low enough price point to keep the features in. Keep in mind that they have larger economies of scale on their products than hobbyists do: they don't do manufacturing runs of just a few dozen units.

I don't know if the plans have changed, but the concept image that was previously on their website had VGA output planned.
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Re: Looking for a good comb filter

Post by energizerfellow‌ »

If you talk to the LaserDisc guys, they'll say the Analog Devices ADV7842 is the best 3D comb filter in the land.

Interestingly, you can get the ADV7842 from Analog Devices as a demo board that has a HDMI output, a ton of analog inputs (including SCART), and a serial console where you can adjust all the options. This is available through your usual electronics suppliers like DigiKey for ~$220.

The only capture cards with a ADV7842 front-end that I'm aware of are from Magewell, but these apparently have the 3D comb feature of the ADV7842 turned off. Magewell boxes are also the only capture cards I've seen that can take sync-on-composite/luma without a sync stripper.
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orange808
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Re: Looking for a good comb filter

Post by orange808 »

energizerfellow‌ wrote:If you talk to the LaserDisc guys, they'll say the Analog Devices ADV7842 is the best 3D comb filter in the land.

Interestingly, you can get the ADV7842 from Analog Devices as a demo board that has a HDMI output, a ton of analog inputs (including SCART), and a serial console where you can adjust all the options. This is available through your usual electronics suppliers like DigiKey for ~$220.

The only capture cards with a ADV7842 front-end that I'm aware of are from Magewell, but these apparently have the 3D comb feature of the ADV7842 turned off. Magewell boxes are also the only capture cards I've seen that can take sync-on-composite/luma without a sync stripper.
I'm sure that one is nice, but is it good for video games?

Comb filter sounds so innocuous. It sounds harmless. :) After all, they have been in "zero*" processing lag displays for decades, but that comb filter is very similar to a deinterlacer.

We aren't guessing on the missing information in a field; instead, we're guessing on the information to remove. To make good guesses, we need a nice big fat frame buffer--and the frame buffer means processing lag.

The DVD recorders that LD guys appreciate also have this kind of complex processing. They work the same way. I have a couple of them. Can't game with them.

I don't believe there are any of these high performance adaptive 3d digital frame-buffered comb filters with low enough lag for gaming. I'll shut up if someone can post one that is, but I've never found one.

We might have better luck looking at the older SVHS machines for a compromise that doesn't add latency.
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Re: Looking for a good comb filter

Post by azmun »

andykara2003 wrote:I’ve been away from the site for a while and am finding it fascinating that some long time RGB people are starting to look at composite for authenticity as a possible alternative, even though they have RGB consoles. I’m interested in this too - I’ve just bought a Megadrive 1 which is supposed to have a terrible composite - I wonder if we’ll eventually get composite mods for retro consoles?

Is it likely that a decent external comb filter would far surpass the ones in even these higher end consumer sets resulting in a much better composite image?
I think our negative perceptions and memories of composite signal (and even RF) may have been a bit exaggerated, thanks in large part to Genesis / Mega Drive model one units and/or televisions that had poor filters. I doubt we'll ever see mod jobs to improve the composite out from retro consoles. Perhaps that would only make sense with Genesis model 1 units but then again you could always opt to get a Genesis 3 for a more convenient solution.
nmalinoski wrote:I think the main desire to use composite over RGB is because there were a number of games that relied on a combination of dithering and how the composite video encoding process treated that dithering (on more modern displays).to cause color blending and transparency effects.
That's definitely a factor for me. But also, sometimes I get so used to the pure and clean colors of RGB signal that I no longer notice them. So I guess it's nice to mix em up a bit. In the end, I've come to appreciate all kinds of video signals from RF to RGB and HDMI.
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Re: Looking for a good comb filter

Post by energizerfellow‌ »

orange808 wrote: I don't believe there are any of these high performance adaptive 3d digital frame-buffered comb filters with low enough lag for gaming. I'll shut up if someone can post one that is, but I've never found one.
Extron DSC 301 HD is a single frame of lag and has a 3D comb filter.
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orange808
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Re: Looking for a good comb filter

Post by orange808 »

energizerfellow‌ wrote: Extron DSC 301 HD is a single frame of lag and has a 3D comb filter.
Could maybe be good. Maybe.

I didn't do any testing with the analog input at all. Did anyone else bother to try it?

I didn't bother to try 240p input. Does it accept 240p? If so, how well does it scale?

How is the comb filter?

Is the lag the same on the analog input?

Fudoh?
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Re: Looking for a good comb filter

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didn't test. Since 480i handling is terrible, I didn't go any further. What's to expect? If 240p works at all, it's certainly treated as 480i and this means increased lag.

It really means nothing that there's a 3D CF in place, results can still be rubbish. Took my years to find a decent setup for laserdisc playback and I don't trust the "next best" video processor if it wasn't specifically aimed at analogue SD in the first place.
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Re: Looking for a good comb filter

Post by andykara2003 »

I tested composite vs RGB on a consumer trinitron and a nice still-sharp consumer shadow mask (Loewe E3001 chassis) using a 1-chip SNES and Megadrive and found that I much preferred RGB on the Loewe than composite on either. The dithering is still there, but the for me, a nice shadow mask set is soft enough while remaining clean to mitigate the dithering to a nice degree. The trinitron's aperture grille is a bit harsh for dithering, but I'll just use the Loewe for those games & have given up on the idea of composite.

I can still appreciate the idea of using composite, but it's not for me.
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Re: Looking for a good comb filter

Post by Fudoh »

for video games it's really a tough concept, but I was blown away when I first tried good comb filters on video material. Best example: when Pioneer (as a media publisher) started to transition from laserdisc to DVD and started to reissue their anime catalogue on DVD, they mostly used analogue tape masters as their source, but what's worse, they used crappy comb filters. If you throw in an early Tenchi Muyo DVD (with the old Pioneer logo with the golden tuning fork) you get rainbows and crazy dot crawl from the DVD (DVD is native component).

If you take the laserdiscs with the same content, run them through a proper comb filter and display the same opening intro, it's a night and day difference. Zero rainbows, zero dot crawl. Easily as big a difference as going composite to s-video for video game sources.

My personal test sequence ever since - just a shame that it requires a native composite source to run the test.
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Re: Looking for a good comb filter

Post by Steamflogger Boss »

Those early Pioneer anime DVDs are some of the worst I've ever seen Fudoh. Knowing all the details it makes even more sense now.

Fortunately Tenchi is on BD but many others the LD is still the best bet.

With something like Project A-ko (not Pioneer but similar situation) the only reason to get the new DVDs is price and availability. AVOID the old DVDs for sure even if they aren't as bad as some of the worst Pioneers releases.
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Re: Looking for a good comb filter

Post by andykara2003 »

Despite my previous comment, I can see what people say when they say that even on a consumer CRT, they find the modern outlook of producing an image that's as sharp and pixellated as possible to look inauthentic - not giving them that nostalgic feel as it's not how they remember their games to be back in the day. This is also why I rarely use my BVM.

I'm buying a 2-chip SNES to compare to my 1-chip on my consumer CRTs. I'd like an image that's softer than RGB+1-chip but still defined. Maybe the RGB from the 2-chip will be soft enough, but I'll try s-video and even composite on it as well to be sure.
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orange808
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Re: Looking for a good comb filter

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Went back through some comb filters over this last week. They were all disappointing. I knew that, but I figured I'd revisit them.

Also got to try a Mitsubishi S-VHS. It was definitely sharp, but there was way too much dot crawl. I've never seen that much dot crawl before.

I have an adjustable comb filter as well. Don't bother with the ones that don't have a frame buffer. This one is lag free, but it introduces artifacts that are more annoying than the original rainbows or dot crawl. Then again, the good ones add lag, so I wouldn't bother with those, either.

Just use an XRGB-1 or 2 and deal with some dot crawl and rainbows.

Also, chaining the XRGB through a video processor (DVDO or Calibre) afterwards while using OSSC linex5 helped a little. I might take a look at the Barco Athena machine and see if it has better noise reduction.
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andykara2003
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Re: Looking for a good comb filter

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What do the XRGB 1/2 units do to get rid of dot crawl?
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Re: Looking for a good comb filter

Post by orange808 »

andykara2003 wrote:What do the XRGB 1/2 units do to get rid of dot crawl?
I guarantee if you saw the output from this Mitsubishi, you'd feel a whole lot better about the XRGB machine. :)

And, if you're super concerned about it, I'd refer you back to Silicon Optix Image Anyplace (IA-100). I think that had a decent comb filter. Not very fast, but no Faroudja will be. Still not going to get rid of rainbows or dot crawl entirely.
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orange808
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Re: Looking for a good comb filter

Post by orange808 »

Since we are all starting to hook up our new Koryuu boxes, does anybody out there have any impressions or screen grabs of the Retrotink 2x composite input after the firmware update?

I've heard the changes made a difference and composite input was improved. I owned and sold a "launch" unit and the comb filter performance was a definite weak spot.

Did anyone try it out?
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Re: Looking for a good comb filter

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Been awhile so I'm curious to see if there is any updates. Using a RGB/Component to Composite encoder still seems like it will give the best results at reducing dot crawl. Are these what I need?

http://www.jrok.com/hardware/RGB.html

https://www.aliexpress.com/item/5028478 ... 6f92bmw1WR
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Re: Looking for a good comb filter

Post by austin532 »

By authentic I mean how I remember it. All of the previous tv's I've had must of had really good comb filters because I don't remember dot crawl being a major issue.
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Re: Looking for a good comb filter

Post by qjkxbmwvz »

austin532 wrote:Most games from that era benefit from composite blending and give that authentic and intended look but their are some non dithering games...
I'm not at all convinced by this argument that the use of dithering implied that composite video was intended. Plenty of arcade games used dithering, plenty of PC games used it, and both of those would involve sharp RGB signals. Plus I remember the lowercase W in Sword of Vermilion turning into a single rainbow smudge on my 3/4 Genesis 2.

Will composite make it look how you remember? Sure. Will it make it look how the developers intended? Maybe, if they had the same revision console as you, and they didn't just make the graphics look good on their PC monitors (the too-wide circles in many SNES games come to mind).
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Re: Looking for a good comb filter

Post by FinalBaton »

austin532 wrote:By authentic I mean how I remember it. All of the previous tv's I've had must of had really good comb filters because I don't remember dot crawl being a major issue.
Actually I think it would have been the opposite.

a really good TV set will give you a real good look at the dot crawl, IME.

no offense

I could be wrong though. but I've never seen a sharp crt that eliminates the NES' dot crawl.
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Re: Looking for a good comb filter

Post by austin532 »

Sony FV300 tv's do a great job hiding the dot crawl. Sure it's still there but it's far less noticeable.
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orange808
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Re: Looking for a good comb filter

Post by orange808 »

If we support the OSSC Pro platform, there will probably be an open source solution to this in the (not so) distant future--and all the processing will share the same frame buffer.
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Re: Looking for a good comb filter

Post by kitty666cats »

Extron YCS 100 isn’t too shabby - has a TBC in addition to the comb filtering.

Very rare, but the Kramer FC-10DXL looks good!

Crystal Vision VPS-1 and Faroudja VS50 also are supposed to be awesome
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orange808
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Re: Looking for a good comb filter

Post by orange808 »

I've tried a couple of those.

I was unimpressed with the Extron YCS 100 for both games and video. The CD 400 looks better with games, but it stinks for video.

The Kramer FC-10DXL doesn't handle 240p properly and the comb filter was no better than the Extron, IMHO.

Didn't like them.

Although, honestly, I can't think of any machines either Kramer or Extron engineered that had great comb filters. Kramer sells some rebranded gear (Extron engineers do everything in house), so the results with some "Kramer" stuff could vary. Although, I wouldn't expect much from the TVOne or Calibre products Kramer sells (in terms of comb filter quality).

For video, most people will want to get an old Pioneer DVD recorder. For games, the Koryuu strikes a nice balance without lag.

I'd recommend getting those or waiting for the OSSC Pro firmware to grow.
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Re: Looking for a good comb filter

Post by kitty666cats »

^ Yeah, I personally use the YCS 100 in a chain, not as a stand-alone device... probably pretty meh whilst flying solo

I’ve heard the Crystal Vision RULES - apparently kinda like the Faroudja VP100 but much better and little to no dot crawl
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