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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sat Feb 27, 2021 2:49 am 


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^^anything is possible, but the short answer is no

^eliminates screen tearing

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sat Feb 27, 2021 8:38 am 


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Does anyone know if it's possible to get 1280x960 mode working with an OSSC? 640x480 works (but horizontal detail is blurry), 1280x720 works (but vertical scaling is uneven), but 1280x960 just causes the OSSC to continuously lose sync. It works if I plug it directly into my monitor, but I need to pass it through the OSSC so I can convert it to HDMI for my capture card.

(Also, why does the GBS Control presets page say "720x480" if it's actually outputting 640x480...?)


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Feb 28, 2021 4:42 pm 


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How's compatibility with modern TVs? I'm thinking of buying a Q60T from Samsung but I worry about signal compatibility. The TV I currently use (a really, really old samsung) whines if I put resoultion in other than 640x480, 1920x1080, and one of those mid tier resolutions (not the NTSC/PAL default ones). I honestly did not want to move on as I'm oddly attached to it but it's giving me problem after problem due to age (it's certainly nice to have VGA + Component + Composite + Optical Out but again, all that analog stuff on it behaves weirdly today).

Also, and forgive me if I'm asking something widely known, but does the HDMI GBS work at all? If there's direct HDMI encoding with the same lag as the VGA GBS I might just assemble another one as I have a spare ESP32 board. I'm having very poor experiences with many VGA to HDMI converters (especially if something other than 1920x1080 is used).


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Feb 28, 2021 5:18 pm 



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The HDMI GBS works with GBSC, few things to consider :

-on board HDMI converter is pretty much lagless like a dongle, but no sound, so depending on your setup it might make things worse
-HDMI output is limited range I believe so set up accordingly
-if you plan to use games with refresh lower than 59.94 you will probably need to play with "lock to 50/60hz" and "htotal ++/--" for your display to sync (even more than with VGA displays), so you might also run into sync line. AFAIK the optional clock board doesn't allow "lock to 50/60hz" nor htotal adjustments.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 01, 2021 4:39 am 


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RoboArmy wrote:
How's compatibility with modern TVs?


I've used my gbs's with various pc crt's, sony trinitron (downscaling), a tcl 49" with various hdmi converters, multiple pc led's/lcd's. Lots of scenarios across those screens, including various adapters and transcoders. The only device I've found that has an issue with any of the resolutions that the gbsc outputs is a dvdo vp30. It will only accept the 720x480 and 1280x720 profiles. All other devices and configurations - zero compatibility issues. YMMV

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 01, 2021 8:01 pm 



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fernan1234 wrote:
Tomrulez wrote:
any idea how to change timing phase / pixel clock? When using the GBS with gbs-control on a Amiga, i get vertical banding / lines. They
are also "normal" when using an Amiga on any LCD that supports 15khz due to timing issues. But on most screens it can be corrected by
adjusting the "pixel clock->PHASE" option of the monitor. So surely it should somehow also be possible on the gbs to adjust it until the
banding disappears?


So this is what this problem comes down to? It would be great if we can do this. Earlier I mentioned having this same kind of vertical noise on PS1 and PS2. I was also able to confirm it's not related necessarily to sync strippers on the cables.


Hi! Yes, seems that way. You have exactly the same problem and on my 15khz displays, I can get rid of it by manual adjusting the phase ... so if we could somehow manual adjust phase sync via gbs-control, it should solve that banding. But we would need some support for this, I have no idea how to accomplish that task.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Wed Mar 03, 2021 8:20 pm 


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Whats the current consensus on the best way to connect an RGB modified console (using SCART cables) to the input of the GBS? Does the GBS input require H and V sync or can I get away with just feeding C Sync to it from the console?

SCART2VGA, custom cable, or just cut a male to female scart cable in half and wire wrap the appropriate wires to the the CGA input pins?

The end game is trying to get my consoles to display on an SVGA CRT with the GBS controls faux scanlines.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 12:14 am 


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Josh128 wrote:
Whats the current consensus on the best way to connect an RGB modified console (using SCART cables) to the input of the GBS? Does the GBS input require H and V sync or can I get away with just feeding C Sync to it from the console?

SCART2VGA, custom cable, or just cut a male to female scart cable in half and wire wrap the appropriate wires to the the CGA input pins?

The end game is trying to get my consoles to display on an SVGA CRT with the GBS controls faux scanlines.


Csync is far more compatible across the board, particularly if you ever want to downscale to 240p. Your own SCART to VGA cable is most likely the cheapest option, but for some consoles (such as PS1 PS2) you’d want to either mod your console for csync or put a LM1881 in the DIY cable. I have heard the GBS will accept sync on luma but I forget if it’s confirmed that it is as issue-free as csync.

The SCART2VGA is nice, if you have a console+cable that are already csync (like NTSC Saturn with a Insurrection Industries cable for instance) then you can disable the LM1881 on it with a switch
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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 4:46 am 


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It works with sync on luma, no problem. Confirmed with ps1 and Saturn model 2.

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 5:18 am 


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NoAffinity wrote:
It works with sync on luma, no problem. Confirmed with ps1 and Saturn model 2.

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And luma sync works fine with 480i -> 240p, right?
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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 9:18 am 



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Hi, new user! Two questions, hope you guys can help.

1) Anyone have issues with white specks appearing? And even more so if you adjust the clockgen to a higher hz rating?

2)
https://github.com/ramapcsx2/gbs-contro ... capacitors

For this mod, how many of these are necessary? I did the 3 on the bottom in the second picture, what do those connect to? Are they redundant if you did C23 C41 C48?


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 1:35 pm 


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Yes, sync-on-luma works great here too. Tested on PS1, PS One and Saturn model 1.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 8:54 pm 


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Modding my Neo Geo CD to hook pin 7 to Luma made my sync issues considerably better, I still have to keep forcing a sync detect reset until the gbs takes the hint and stops with the "heatwaves" and desyncing, but it's nowhere as annoying as it was before. PS1 seems good too and I only had issues where the GBS couldn't establish proper sync levels once (random desyncs on bright screens).

I'd use CSync if at all possible but luma seems a solid second option.

-----

My new TV arrived and the GBS plays nice with it, but it makes the trailing shadow effect I was having very noticeable. I guess it shows up less on my capture?

https://www.youtube.com/watch?v=peVfIr2TORw

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I really need to dig into the thread to see the fixes you guys have made for this kind of stuff.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 10:55 pm 


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Anyone in here messed around with chaining this before some random cheaper-than-$100 processors/scalers (Kramer, Extron, brands like that)?

Daydreaming of using GBSC with a secondary scaler that outputs either 1600x1200 or, ideally, 1920x1440 (I know, quite a niche resolution for processors/scalers) @ 60 Hz via RGBHV/“VGA” to be used on a high-end PC CRT monitor. A Mitsubishi Diamond Pro 930SB-BK to be exact :)

I suppose a scaler with HDMI out would be alright too, as my Portta HDMI to VGA should “top out” at 1920x1440 60Hz range. I know, “just get a OSSC” but you can get some of these older scalers for around $20 or maybe even less if you’re patient/know where to look
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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 04, 2021 11:53 pm 


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kitty666cats wrote:
Anyone in here messed around with chaining this before some random cheaper-than-$100 processors/scalers (Kramer, Extron, brands like that)?

Daydreaming of using GBSC with a secondary scaler that outputs either 1600x1200 or, ideally, 1920x1440 (I know, quite a niche resolution for processors/scalers) @ 60 Hz via RGBHV/“VGA” to be used on a high-end PC CRT monitor. A Mitsubishi Diamond Pro 930SB-BK to be exact :)

I suppose a scaler with HDMI out would be alright too, as my Portta HDMI to VGA should “top out” at 1920x1440 60Hz range. I know, “just get a OSSC” but you can get some of these older scalers for around $20 or maybe even less if you’re patient/know where to look


1440p probably isn't going to happen for you. I can't think of anything inexpensive that does 1440p.

Don't worry about 4:2:2 sampling from a second processor. I looked over the docs for the Gonbes video chip. The "oversampling" seems to be poorly named and it's purely a noise reduction feature. It appears to be "redundant sampling" or "multisampling". If I understand correctly, 4:4:4 samples are taken multiple times, but it's not taken in smaller increments, so that won't offset the 4:2:2 compression step (that always happens before processing).

A DVDO is the fastest option. The signal has already lost color information, so 4:2:2 won't matter. The HD+, VP20, 30, 50, and 50 pro are all programmable. They might do UXGA. That's not much more work than 1080p.

I don't know of any "sub 1 frame" Kramer or Extron machines.
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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 05, 2021 1:41 am 


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I’m not overly-concerned when it comes to lag - I ain’t a speedrunner, heh.

I noticed that the Kramer VM-425 supports 1600x1200 out and that thing is dirt cheap (though that would need a HDMI to VGA / the unit even LOOKS cheap) - however, I still need to pore over specs on many of the Extron offerings, and also double check on some obscure stuff too (Dido Jr / Dido LT and their programmable resolutions come to mind, though I forget if they are really ANY good aside from the Jr’s decent TATE/240p downscaling capability). SI Optix Anyplace units have been pretty abundant on eBay lately, too.

Come to think of it, going back to my “not caring about some lag” - this little foray I am pondering, I’m really just aiming for image quality over fast processing. Any standouts flashing back to your mind from all your years trying out many of these devices?

EDIT: Ahh, the Dido LT can handle 90kHz... 1920x1440 @ 60Hz could be entirely feasible, as aforementioned res is just under 90 (but lord knows if the software has some forced limits for user-made resolutions, despite being technically ‘within spec’)
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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 05, 2021 1:47 am 



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I really wanted an Optix Anyplace last year until I realized that the RGB input is only for PC inputs and doesn't take SDTV signals (let alone 240p 15khz). It only takes them via the YPbPr, but who uses that!? :lol:

Seems to be a general limitation of most of these video processors. I want that that I can just drop into my RGB setup seamlessly. There's really nothing other than to wait for the OSSC Pro.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 05, 2021 4:44 am 


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Lodey wrote:
Hi, new user! Two questions, hope you guys can help.

1) Anyone have issues with white specks appearing? And even more so if you adjust the clockgen to a higher hz rating?

2)
https://github.com/ramapcsx2/gbs-contro ... capacitors

For this mod, how many of these are necessary? I did the 3 on the bottom in the second picture, what do those connect to? Are they redundant if you did C23 C41 C48?
Cant speak to #1. How are you increasing clock gen frequency?

2) the pictures show the same solution in different soldered locations. As you said, they would be redundant if you soldered caps in both locations.

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 05, 2021 7:13 am 



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xeos wrote:
rama wrote:
Many thanks for both of your reports :)

I'm currently trying to nail down some image positioning and geometry issues that seem to plague PAL video modes / using the 50Hz output settings.
Once that is done, I can investigate those hiccups and start thinking about some user controls.
Also, the YPbPr and HDMI output methods need some work.
(HDMI, as used on the blue new GBS boards, has wrong colors. YPbPr most likely needs the hardware resistor modification for proper colors.)

I don't think I can reduce the lag any more. It already is somewhere close to just 16ms, which is half of a "low lag" device.
The line double mode in the Scaler IC is interesting nevertheless, because it might allow me to bypass some processing.

Last but not least, I want to try to get the ADC sampling phase correct. Right now, it is randomly aligning or not aligning.
If I get this right, I can disable many filters and deliver absolutely razor sharp pixels ;)


So the lag is less than a stock GBS 8200? I measured a board with what appears to be same chip and found it had 16ms of lag + drifting lag of 0...16ms (ie lag varied from 16ms to 32ms) over the period of about a minute. You figured out how to make it constant?


Getting the ADC sampling phase correct goes some way in the same direction as the "phase" settings on TFTs? :) So if, then we could get rid of that
banding - would it be possible to ask for an option for manual correction from the automatic sensed values?

On old home computers it seems to be worse than on most consoles, because they seem to not have perfect constant pixel draw timings - a CRT does not care, as it has no real pixels behind the mask, so getting a slightly stretched "pixel" and than a slightly shorter one during drawing the line doesn't hurt as it just draws a constant line behind the screen mask... but when "collecting" the drawn line before the sync signal and putting a pixel raster over it can sometimes result in banding. Interesting, when correcting phase on some TFTs, you find a spot where the banding disappears because alignment is improved - so a option for manual override/correction can be benificial?!


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 05, 2021 6:29 pm 


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Got all my parts in for the project except for a SCART>DE-15 adapter. I do have the frankenstein VGA+1/8" audio >SCART cable I built to play with GroovyMAME on my Trinitron Wega set, I may be able to use that.

Question though-- I ordered a WeMos CH D40 Arduino board and a smaller mini NodeMCU board for the project. I have the larger WeMos board in hand but am still waiting on the NodeMCU. Is there any appreciable difference in quality / functionality between the two other than size? I'd like to maybe work on the project this weekend, is there any reason I should hold off and use the NodeMCU instead?


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 2:27 am 


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Got the electronics build finished, but have no idea if it works. Getting the following error when trying to verify/compile the gbs-control.ino. Tried this on two different PCs and get the same error. Followed the instructions at https://github.com/ramapcsx2/gbs-contro ... ware-Setup just as they are written. Im dead in the water. Anybody have a clue whats going on here? Rama?

Last few lines:
Code:
C:\Users\Josh\Downloads\gbs-control-master\gbs-control-master\gbs-control/gbs-control.ino:8156: undefined reference to `WebSocketsServer::~WebSocketsServer()'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board LOLIN(WEMOS) D1 R2 & mini.



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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 5:33 am 


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I believe you have to remove the "-master" from the folder name. Also, sometimes when downloading from github and unzipping, the files will be in a subfolder. They should not be in a sub folder.

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 1:51 pm 


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Fantastic, thanks a million. The Github wiki is really quite unclear at certain points, that one in particular for example. It could use a tune up in the walk-through for folks not familiar with Arduino software usage.

Anyways, once it compiled, I uploaded it and it worked right off the bat. I used a pretty frankenstein setup of Genesis 2>AV Specialties SCART to YUV Converter>Atlona Component Cable In to GBS-8200>DE-15/VGA out to Compaq FS-7600 SVGA monitor. Even with all the things that could go wrong from throwing in that component converter (I didnt have the cabling to go directly from SCART to DE-15 in), the results are still awesome. To think the image might actually improve with direct RGBS in is pretty mind blowing. I notice zero ringing, bleeding, tearing, or lag. The image is not as bright as the mythical 240p120 Im so fond of but aside from that its pretty fucking fantastic.

The WiFi interface is fantastic, and instantaneous. You click an adjustment parameter on the web interface controls, you see the change on screen the instant you click the button. For those looking to feed a VGA CRT like this, I find the best config is full scanlines (0%), line filter off, peaking on, step response on.

I made a gallery of screenshots taken with my phone, they dont quite do it justice as it looks even better in person. For a setup that literally cost me about $30-$35 USD, this is absolutely untouchable in terms of bang for the buck, and it was very fun to put together as well. All it needs is a nice shell/case

https://imgur.com/gallery/5xESX9W

Sneak peek:
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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 2:32 pm 



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Good to see you got it working. Looks great. I'm guessing that's using 640x480, which should be good on PC CRTs.

Josh128 wrote:
For those looking to feed a VGA CRT like this, I find the best config is full scanlines (0%), line filter off, peaking on, step response on.


I wonder why the web interface says scanlines look best with line filter enabled. I find that even on flat panels all they do is make the picture less sharp (one advantage is to reduce video noise, such as from phase issues mentioned earlier). Don't think I noticed what difference step response makes though.

Looking at those pictures I'm also reminded of one of the limitations of the GBS, which is that even with full scanlines some colors cannot be struck out completely, blue being the most obvious. It's a bit unfortunate that scanlines cannot be "perfect".


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 2:59 pm 


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Glad to hear my advice helped. I remember running into a similar or maybe the same problem and having to figure that one out. :)

Looks great!

I personally get pretty decent scanlines at 480p, on my 21" sun trinitron crt vga monitor. They are pretty good on a viewsonic 19" as well. Turning on scanlines in gbs doesnt seem to do anything when there are native visible scanlines.

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 3:32 pm 


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Josh128 wrote:
Fantastic, thanks a million. The Github wiki is really quite unclear at certain points, that one in particular for example. It could use a tune up in the walk-through for folks not familiar with Arduino software usage.

Anyways, once it compiled, I uploaded it and it worked right off the bat. I used a pretty frankenstein setup of Genesis 2>AV Specialties SCART to YUV Converter>Atlona Component Cable In to GBS-8200>DE-15/VGA out to Compaq FS-7600 SVGA monitor. Even with all the things that could go wrong from throwing in that component converter (I didnt have the cabling to go directly from SCART to DE-15 in), the results are still awesome. To think the image might actually improve with direct RGBS in is pretty mind blowing. I notice zero ringing, bleeding, tearing, or lag. The image is not as bright as the mythical 240p120 Im so fond of but aside from that its pretty fucking fantastic.

The WiFi interface is fantastic, and instantaneous. You click an adjustment parameter on the web interface controls, you see the change on screen the instant you click the button. For those looking to feed a VGA CRT like this, I find the best config is full scanlines (0%), line filter off, peaking on, step response on.

I made a gallery of screenshots taken with my phone, they dont quite do it justice as it looks even better in person. For a setup that literally cost me about $30-$35 USD, this is absolutely untouchable in terms of bang for the buck, and it was very fun to put together as well. All it needs is a nice shell/case


You might want to keep the YPbPr converter in line, as long as your colors look good. Straight RGB might give you a slightly sharper image or more accurate colors, but you are not missing much. YPbPr component video is every bit as good as RGBs, at least at these resolutions it is. Also, I noticed the last time that I took my GBS-C setup out that it seemed to be more reliable over component. It was the only way I could get a stable image from my Dreamcast. It's sort of a no-bullshit option, especially if you do not already have a good way to get RGB from your Genesis in to the Gonbes.

I input 15KHz RGB in to the board via a SyncStrike using the Strike's screw terminal outputs connected to the big pin RGB input on the Gonbes. If I didn't have a SyncStrike already, I would use the custom VGA cable I made where I lifted the H sync pin to go from my VGA switcher to the DE15 input on the Gonbes. I have a mostly DE15 based setup, but some of my cables output C and H sync simultaneously and it gives the GBS-C a seizure. It looks like you can solder, so you should just install a female SCART connector on the 5-pin jumbo connector if you want compatibility with cheap RGB cables. People do that.

Get a copy of Artemios 240p Test Suite for your Genesis (or, ideally, any other system if you can) and tune that Compaq. It should be capable of a brighter image, and if not, replace it! Those things are all over around here. Anyway, that is the first thing that I do with a new CRT setup. If you do not have a flashcart, there are websites that sell the test suite on its own cartridge for not too much money.

At what resolution are you running your monitor? It should be capable of 1024x768.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 4:06 pm 


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fernan1234 wrote:
Good to see you got it working. Looks great. I'm guessing that's using 640x480, which should be good on PC CRTs.

Josh128 wrote:
For those looking to feed a VGA CRT like this, I find the best config is full scanlines (0%), line filter off, peaking on, step response on.


I wonder why the web interface says scanlines look best with line filter enabled. I find that even on flat panels all they do is make the picture less sharp (one advantage is to reduce video noise, such as from phase issues mentioned earlier). Don't think I noticed what difference step response makes though.

Looking at those pictures I'm also reminded of one of the limitations of the GBS, which is that even with full scanlines some colors cannot be struck out completely, blue being the most obvious. It's a bit unfortunate that scanlines cannot be "perfect".


Yes, to clarify, the setup above is using the 640x480 output with full (0%) artificial scanlines. Im guessing the suggestion for the line filter with artificial scanlines is when using a 1080p or higher LCD panel. Due to the sharp edges of pixels in such a display, it may produce a more pleasing CRT-like image, but on an actual CRT, it completely blurs the image and the scanlines themselves. Its not even a question, you definitely will want it off.

Looking at the picture of Arthur vs my previous 240p120 testing pics, I see what you mean about the color bleed (blue in particular) in between the scanlines. I need to double check and make sure thats actually present on the monitor and not just from the picture taken by my phone. Are you sure that its a limitation of the GBS-8200 and not my SCART>YUV converter though? I would like to remove the converter from the chain and verify that for sure.

**EDIT-- It is indeed present in the actual image. However, I will say that its very subtle and I didnt even notice it until you said something and I still think it looks really great in person. That minor bleed might actually help the entire image brightness a bit. Still not sure though if its from the GBS or my component converter though. Need further testing.


NoAffinity wrote:
Looks great!

I personally get pretty decent scanlines at 480p, on my 21" sun trinitron crt vga monitor. They are pretty good on a viewsonic 19" as well. Turning on scanlines in gbs doesnt seem to do anything when there are native visible scanlines.


Yes, thank so much again, I much appreciate it. So when you run 240p content @ 480p, you dont use the GBS scanline function? I find it looks good either way but you dont get that true SD CRT 240p look (my preference) without them. Without them it looks much like an emulator would with no scanlines, just line doubled to 480p.


SCARTicus wrote:
You might want to keep the YPbPr converter in line, as long as your colors look good. Straight RGB might give you a slightly sharper image or more accurate colors, but you are not missing much. YPbPr component video is every bit as good as RGBs, at least at these resolutions it is. Also, I noticed the last time that I took my GBS-C setup out that it seemed to be more reliable over component. It was the only way I could get a stable image from my Dreamcast. It's sort of a no-bullshit option, especially if you do not already have a good way to get RGB from your Genesis in to the Gonbes.

I input 15KHz RGB in to the board via a SyncStrike using the Strike's screw terminal outputs connected to the big pin RGB input on the Gonbes. If I didn't have a SyncStrike already, I would use the custom VGA cable I made where I lifted the H sync pin to go from my VGA switcher to the DE15 input on the Gonbes. I have a mostly DE15 based setup, but some of my cables output C and H sync simultaneously and it gives the GBS-C a seizure.

Get a copy of Artemios 240p Test Suite for your Genesis (or, ideally, any other system if you can) and tune that Compaq. It should be capable of a brighter image, and if not, replace it! Those things are all over around here. Anyway, that is the first thing that I do with a new CRT setup. If you do not have a flashcart, there are websites that sell the test suite on its own cartridge for not too much money.


I agree component is basically equal, but this converter I am using is probably not tuned to the correct colors and may perhaps not be quite as sharp as an untouched RGB signal, but that remains to be seen. My top reason for wanting to remove it would be mostly to simplify the signal chain and have less cabling and boxes, lol.

Im running a Mega ED Pro but for some reason I dont have the 240p suite on it. I intend to get it. I do have it for my SNES Everdrive though, was damned useful in tuning my 36" Wega. I just threw this together this morning and was tinkering once NoAffinity helped me out on the compiling issue. I have 6 SVGA monitors (!) but theres nothing wrong with this one. Its bright enough, I was just referencing the brightness vs the RetroArch 240p120 testing I had done (on the same monitor). The 240p120 brightness is always going to be unobtainable at 480p60 w/ faux scanlines, regardless of the settings.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Sun Mar 07, 2021 5:40 pm 



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Posts: 1316
Josh128 wrote:
**EDIT-- It is indeed present in the actual image. However, I will say that its very subtle and I didnt even notice it until you said something and I still think it looks really great in person. That minor bleed might actually help the entire image brightness a bit. Still not sure though if its from the GBS or my component converter though. Need further testing.


It's not your converter. It's a limitation on the chip used on the GBS. This is one of rama's comments on it:

Quote:
The scanline "strength" is a neat side effect of abusing one of the chip features.
I know that it barely blends blue, for example. It is an overall pleasing effect this way (to me at least), but yeah, it can't really produce entirely black scanlines.


https://github.com/ramapcsx2/gbs-contro ... -628380956

He also makes a suggestion there about the possibility of using an external scanline circuit. You do make a good point that these not being fully empty scanlines for some colors will help a little bit with brightness, at least when those colors are present.


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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 12:57 pm 


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Its interesting. Not all colors are impacted by the issue, several are but some less than others. The primary color blue is definitely the worst. When looking a solid patch of true blue, its almost as if there are no scanlines at all! Light /sky blue is fine, with nice defined lines, but the closer to primary you get, the worse the issue. Primary red is next. There are still visible scanlines, but they are quite attenuated. Magenta is also affected but oddly enough, seems to be a bit better than pure red. Primary green seems to be the least affected, but the scanlines in it are definitely less pronounced than in pure whites , yellows, sky blues, and grays, which are the least affected.

Its interesting, but I do tend to agree with Rama that this may actually be a positive as far as image quality, because it produces a nice overall image with good looking scanlines that are not too intrusive, with the benefit of additional brightness over what you would see with pure black scanlines from an emulator, for example. Below are some screenshots I took of the 240p suite with my phone of color bars that show the different scanline intensities on different colors.

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 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 1:16 pm 



Joined: 14 Aug 2017
Posts: 1316
It's not bad looking, but it's also kind of backward because on a CRT something like white would precisely have less space between the scanlines (or put in other words, the blank "scanlines" would be thinner). Whereas blue lines would definitely be thinner (or thicker blank "scanlines" in between blue).

So if the goal is to emulate how a CRT looks, what hybrid scanlines can do on an OSSC is way better. But if the goal is simply a pleasing image, then this can be more than fine, and based on taste and circumstances it may even be preferable to some.


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