GBS 8200/8220 CFW Project

NoAffinity · Joined: 07 May 2018 Posts: 719 Location: Escondido, CA, USA

fernan1234 wrote:

On another subject, I'm wondering if anyone has noticed vertical line noise on the video from a source with sync strippers. I was testing a bunch of my consoles with the GBSC today and noticed this kind of noise only from my PS1 and PS2, and I believe the cables I have for those happen to have sync strippers, so I suspect that may be the cause.

The noise is much less noticeable on the 480p and 1080p output (virtually gone on the latter), but 480p looks kinda blurry on my setup at least and 1080p doesn't work well with 240p scanlines, so it is a problem given that it's very noticeable on the 1280x960 output mode which is the one I prefer for cleanest picture and scanlines. Turning on line filter also helps since it adds a bit of blur to the picture. If it turns out to be due to the sync strippers on the cables I'm going to look for some alternatives.

Did some testing this morning, with good results. I have an LM1881 sync stripper on the RGBS/audio RCA output of my 6-port Otaku scart switch.

I tested the following:
SNES Mini (the original mini, not the newfangled miniature/HDMI version) w/ RGB mod and dejitter mod, csync
PS1 SPCH-1001 w/ Xstation, luma sync
Sega Genesis Model 2 w/ 3BP, csync
N64 w/ N64RGB, csync

Everything worked flawlessly, with the exception of the SNES. It kept losing syncing, and the image was jumpy. Turning SyncWatcher off fixed it. Whenever power cycling the system, I would have to turn syncwatcher on and back off. Once this was done, it worked flawlessly as well.

Not vertical lines or noise or any other anomalies, just high quality, low-lag scaling on the cheap.

fernan1234 · Joined: 14 Aug 2017 Posts: 1193

NoAffinity wrote:

Not vertical lines or noise or any other anomalies, just high quality, low-lag scaling on the cheap.

Thanks for sharing your test results! Looks like I'm gonna have to do some troubleshooting.

I was suspecting the sync strippers that Retro Access put on my RGB cables for PS1 and PS2, not sure which ones they used. The cables are custom made for DE15 connectors, and I guess RA assumes you need sync strippers on those for compatibility with Extron gear, but it looks like that's not necessary with the VGA Ars switch I use, so maybe I would just need to remove the strippers and just pass the original luma sync to the V pin. This is again assuming that this is the root of the vertical bars noise problem, because it's only these two console and that's the only common factor I can think of.

fernan1234 · Joined: 14 Aug 2017 Posts: 1193

Don't have my GBS hooked up now so can't check, but could anyone tell me what is the best way to handle games that support 16:9 anamorphic widescreen?

NoAffinity · Joined: 07 May 2018 Posts: 719 Location: Escondido, CA, USA

If you want to display in 16:9, the 1280x720 profile is 16:9. All other profiles are 4:3, including 1920x1080 which scales to 4:3 within a 16:9 canvas.

Sent from my SM-G955U using Tapatalk

fernan1234 · Joined: 14 Aug 2017 Posts: 1193

NoAffinity wrote:

If you want to display in 16:9, the 1280x720 profile is 16:9. All other profiles are 4:3, including 1920x1080 which scales to 4:3 within a 16:9 canvas.

Sent from my SM-G955U using Tapatalk

Thanks for the info. That's kind of a shame though since the 720p mode doesn't look nearly as good as most of the others, at least on my monitor.

kitty666cats · Joined: 05 Nov 2019 Posts: 651 Location: Massachusetts, USA

As much as I love my goofy enclosure, I could theoretically sell off my input and output cables (Tektronix Sync Combiner cables are randomly worth a mint) and connect these badbois to the input and output, respectively:

https://www.retroupgrades.co.uk/product ... a-adapter/
https://www.retroupgrades.co.uk/product/vga2scart/

Would result in one hefty pile of PCB

maxtherabbit · Joined: 05 Mar 2018 Posts: 1420

that tek cable is cool but I can't imaging paying big money for it when a $5 used extron box from ebay does the same thing

Tomrulez · Joined: 18 Feb 2021 Posts: 1

Hi there,

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?

Thanks!

kitty666cats · Joined: 05 Nov 2019 Posts: 651 Location: Massachusetts, USA

maxtherabbit wrote:

that tek cable is cool but I can't imaging paying big money for it when a $5 used extron box from ebay does the same thing

I got it for ~$20, no way in hell would I pay what people out there ask lol. I like not having yet another Extron wall-wart

Lodey · Joined: 21 Feb 2021 Posts: 3

Hey guys!

Recently put one of these GBS-8200s together and wanted to check in with you guys on an issue I'm having. Basically, I installed the clockgen mod, even though I wasn't getting screen tearing before, but now I definitely get it. I hear you can dial in the settings, but going higher on the hz makes white specks appear on my screen. Any idea what's causing this?

Mods installed:
8266
Clockgen
C11 with new cap
potentiometer removal and bridges
I also soldered the usb from my HDMI adapter to the board.

I'm testing with a PS2 that's using PS3 official component cables. Any idea where I should go from here? I heard some people put copper tape on the ram traces, so maybe someone could also take a picture circling which ones those are on the back?

I also haven't done the 10uf SMD cap replacement yet, but that supposedly can help with noise, but many have reported it does nothing?

Lodey · Joined: 21 Feb 2021 Posts: 3

Anyone know why I'm getting white specks after installing the clockgen mod? Also getting screentearing now, but didn't before installing it.

TABYDACAT · Joined: 27 Dec 2020 Posts: 3

AndehX wrote:

TABYDACAT wrote:

I saw earlier in this thread that someone thought it would be nice to have physical buttons to select/load their custom presets. As a side thing I wanted to work on, I decided to give it a try. This edit is kinda messy, but through testing, I haven't noticed hiccups to the actual use of the device during gameplay. OLEDs can now be used to display which preset is being selected/loaded, boot-up messages, and various GBS data (resolution, input, etc.).

No idea if this would actually be useful, but if this sounds like something interesting, I can send around the edit. I already have a to-do list for this, but perhaps some others have good feedback for the functionality or aesthetics. The hardware needed to actually use this is straightforward, consisting of three components: SSD1306 128x64 I2C OLED and two toggle push buttons.

Some other things to note:
- SCART, VGA and Component were used to test (PS1,Dreamcast and PS2)
- I opted to use this particular OLED due to size, cost and availability. Could change in the future to use LCD screens or perhaps both that way users have an option on what they want to use.
- Different configs of this OLED don't matter, like color. Just make sure the size and comm. method is the same
- I'm still working on this so expect weird or unusual things, particularly the OLED functionality.

When taking this photo no input was connected hence the bypass and interesting refresh rate, after some time it will blink "No Signal"
Here's a some example photos:

Spoiler: show

EDIT: I've now completed this edit to a usable state and soldered to a protoboard in the mean-time. There is some minor issues software-wise, but that will fix be shortly. Here's some crappy pictures to illustrate an example of a GBS 8200 with an OLED. Using a PS1 via SCART. I forgot to picture this, but you can might able to see the two buttons that control the loading/selecting of the presets.

Spoiler: show

Do you have any updates on this? a guide to build it etc? I would love to make something like that.

I'm terribly sorry for the long duration between replies for this. I have made a quick guide to get this up and running (there's probably typos lol). Even though its pretty simple to get everything connected, I wanted the guide to be somewhat detailed. If there's anything that needs to be addressed and that isn't in the guide already, please let me know. Can't wait to see this running in others setups!

Guide:

Spoiler: show

strayan · Joined: 19 Mar 2017 Posts: 416

Chipnetics wrote:

Hi everyone - I'm the dude who currently sells the pre-assembled GBS8200 units on Tindie

Holy moly what happened to the price!? I was about to buy another one from you only to discover it went up USD$34

ldeveraux · Joined: 01 Mar 2018 Posts: 640

strayan wrote:

Chipnetics wrote:

Hi everyone - I'm the dude who currently sells the pre-assembled GBS8200 units on Tindie

Holy moly what happened to the price!? I was about to buy another one from you only to discover it went up USD$34

It's the same price as in November when I bought it...

strayan · Joined: 19 Mar 2017 Posts: 416

ldeveraux wrote:

strayan wrote:

Chipnetics wrote:

Hi everyone - I'm the dude who currently sells the pre-assembled GBS8200 units on Tindie

Holy moly what happened to the price!? I was about to buy another one from you only to discover it went up USD$34

It's the same price as in November when I bought it...

Paid 79.99 in September (incl. clock gen mod). Asking price now $113.99

fernan1234 · Joined: 14 Aug 2017 Posts: 1193

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. I did take a pic yesterday:

strayan wrote:

Paid 79.99 in September (incl. clock gen mod). Asking price now $113.99

Sounds like September was the last best time to buy one. Wish I knew back then! I got mine in November for $113.99, plus shipping.

ldeveraux · Joined: 01 Mar 2018 Posts: 640

strayan wrote:

Paid 79.99 in September (incl. clock gen mod). Asking price now $113.99

Oh you're including the clockgen mod. Right, looks like it has gone up since November even, as I paid $99.99 with CGM. I didn't even realize it was different, I looked at the site, looked at my receipt, same amount!

xeos · Joined: 20 Oct 2016 Posts: 95

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?

NoAffinity · Joined: 07 May 2018 Posts: 719 Location: Escondido, CA, USA

^check out the review on retrorgb. I believe Bob also confirmed the bad and inconsistent lag of the stock board, and the significant improvement created by the custom firmware.

Sent from my SM-G955U using Tapatalk

xeos · Joined: 20 Oct 2016 Posts: 95

NoAffinity wrote:

^check out the review on retrorgb. I believe Bob also confirmed the bad and inconsistent lag of the stock board, and the significant improvement created by the custom firmware.

Sent from my SM-G955U using Tapatalk

I think what bob is talking about is the option of using BOB deinterlacing (there's a good pun there, somewhere). But the GBS-control docs themselves say

"no synchronization loss switching 240p/480i (output runs independent from input, sync to display never drops)"

which would mean that the lag would vary by 16ms over time.

NoAffinity · Joined: 07 May 2018 Posts: 719 Location: Escondido, CA, USA

Some of us did lag testing a while back and I believe confirmed <1 frame from gbsc. Rama was surprised at the results. I'm going from memory, dig around in this thread, and you will find the results eventually.

Sent from my SM-G955U using Tapatalk

fernan1234 · Joined: 14 Aug 2017 Posts: 1193

Does anyone have recommendations for VGA to HDMI converters that output RGB 4:4:4 full? I have the previously recommended Monoprice converter and it works quite nicely with a good picture and no resolution/scan rate change dropouts with a clockgen installed, but it outputs YCbCr 4:4:4 and I suspect it has some red bias as some blues appear a bit purplish. I could try adjusting the RGB gain on the GBSControl menu but would prefer not to mess with those, and ideally want to keep the whole chain in RGB.

I'm thinking an OSSC's VA3 input in passthrough mode could be a good solution. Anyone have experience pairing these two?

xeos · Joined: 20 Oct 2016 Posts: 95

rama wrote:

Hey cryptblood1986,
Gunstar:
CRTs make this stuff look really awesome. Nice shots!
And yeah, between half and a full frame of lag is required. 8 to 16.6ms, ~12ms average.
You could have maybe 5 of these in a chain, before you notice lag

Found this from a while back in the posts.

So the 8200 CFW still has the rolling lag issue. While 12ms sounds good, keep in mind that constantly varying lag is the worst kind. You can't adapt to it; your brain never learns what the delay is between button mashing and results, so for instance you'll miss tricky jumps, etc. because you'll push the button too soon or too late.

Anybody know why the rolling lag is only half a frame though? I would expect it to be 0...16ms + some small fixed amount for signal digitization. That's what I've seen in every device that has the rolling lag issue (eg https://alantechreview.blogspot.com/202 ... -dont.html).

laikmike · Joined: 31 Jan 2020 Posts: 17 Location: Mexico

Hello guys, hope you can help me , im trying to downscale my wii to 240p, but the signals comes from a hdmi to vga (because im capturing the component on hauppage 2) but when i set it to downscale to 240p and output component i got this sync problem?
image:
https://imgur.com/xdIZWkB

NoAffinity · Joined: 07 May 2018 Posts: 719 Location: Escondido, CA, USA

^vga downsacling does not work. Use the wii component output to gbsc.

^^I spend a lot of time on various games across multiple platforms and screens/scalers/line multipliers (and various combinations of all). I dont notice any difference between ossc and gbsc. A slight adjustment for, say, arcade vs osss or arcade vs gbsc, but the adjustment is the same, comparing gbsc to ossc. YMMV

Sent from my SM-G955U using Tapatalk

awe444 · Joined: 27 Apr 2015 Posts: 123 Location: New York

NoAffinity wrote:

^vga downsacling does not work. Use the wii component output to gbsc.

Is the fact that it can only downscale from the component input a hardware limitation? Or would downscaling of RGB 480p be a possible feature at some point? Also, since his setup was using a HDMI to VGA converter, would a HDMI to component converter, fed into the GBS component input, be an option?

awe444 wrote:

NoAffinity wrote:

I believe rama said the hardware is not capable of outputting an interlaced signal

Can it at least passthrough (or transcode only without scaling) a 480i signal? I bought one of the preassembled units (the second batch, which I believe hasn’t shipped yet) under the assumption it could at least transcode a 480i RGB signal to 480i YPbPr. I’ll still have use for it if not, but still would like clarification if anyone’s tested that.

I received my unit and tested this— it seems the GBS cannot transcode RGB 480i to YPbPr 480i. I get a rolling image indicative of bad sync. I’ve confirmed that YPbPr 480i as input cannot be output as 480i either (“Passthrough” preset gives the same rolling image). However, 480i YPbPr does output as 240p YPbPr using downscale mode, which is kind of nice.

awe444 wrote:

fernan1234 wrote:

downscaling them to 240p may look neat as a novelty but you'll be missing half the fields of the picture.

If it’s downscaling to 240p by discarding every other line of the 480p input, then yes, half the signal information is indeed lost. On the other hand if it’s averaging consecutive pairs of lines, then the argument could be made that the information isn’t lost because the averaged lines would contain smoothed out details, kind of like how antialiasing works except in just one dimension. The Super Emotia units downscale via the averaging method. Easiest way to test if it’s discarding or averaging is to feed it a 480p native checkerboard test pattern: if it outputs in 240p as vertical lines, then it’s discarding, if it outputs a solid gray color then it’s averaging.

I also tested this and found that it downscales by the “discard every other line” method rather than averaging. So for a 480p native game this does indeed lose half the information.

strayan · Joined: 19 Mar 2017 Posts: 416

awe444 wrote:

Is the fact that it can only downscale from the component input a hardware limitation? Or would downscaling of RGB 480p be a possible feature at some point? Also, since his setup was using a HDMI to VGA converter, would a HDMI to component converter, fed into the GBS component input, be an option?

Downscaling from RGB is possible but only from 480p RGBs, not RGBHV.

awe444 wrote:

Also, since his setup was using a HDMI to VGA converter, would a HDMI to component converter, fed into the GBS component input, be an option?

Yes

kitty666cats · Joined: 05 Nov 2019 Posts: 651 Location: Massachusetts, USA

laikmike wrote:

Hello guys, hope you can help me , im trying to downscale my wii to 240p, but the signals comes from a hdmi to vga (because im capturing the component on hauppage 2) but when i set it to downscale to 240p and output component i got this sync problem?
image:
https://imgur.com/xdIZWkB

https://www.retroupgrades.co.uk/product/vga2scart/

^ This will change the RGBHV from VGA to RGBS, which will alleviate your problem. Alternately, you could use an Extron RGB interface to combine sync and use a BNC to VGA cable to connect to the GBS

You could also use Wii component cables, if you already have 'em (if not, some new component cables are also probably cheaper than this device - however, it is a potentially handy thing to have around!)

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