GBS 8200/8220 CFW Project

[keremimo]

Enjoying this immensely so far on my CRT monitor

Rama, how possible would it be to write our own presets? I already know a modeline that I want to work with, because my capture card doesn't fancy the available resolutions on 50hz (or 60hz for that matter)

I tried looking everywhere in the code to input the modeline below:
ModeLine "1280x720" 74.25 1280 1720 1760 1980 720 725 730 750 +HSync +VSync

720p in 50hz, HDMI compliant as well ^

But no luck. I changed some stuff in the gbs-control.ino, the lines which had 1280x960 in it, calculated every variable and inputted them... Nope. Still displays a 1280x960 image that most capture cards hate

Edit: Looking back the older commits actually had 720p :O can we have those back? (CRT monitors resize them to 4:3 anyways and most capture cards play nice with the resolution)

Please, Rama (old commits give various errors trying to compile for ESP8266)

[rama]

culexus: I haven't tested with the XBOX yet but I see no reason its 720p shouldn't work

Syntax:
Not sure I understand what you want to do. The GBS has simple flags that toggle YPbPr to RGB conversion and back.
Currently it has to apply all the format conversion etc, so it is not a passthrough device with conversion.
It may be possible to do that though, using the various bypass flags and configuring the processing blocks to deal with this.
It requires a lot more reverse engineering though, and no guarantee that it even works.
Incidently, this would be similar to configuring the device for line doubling only mode, which could be pretty nice, too.

keremimo:
It wouldn't be too hard to drop the vlines to 720p.
The question then is: How do you want to access these new modes?
Should it be a web ui option? Should it be permanent for all sources, or should it somehow be smart about it?
I think I can whip up 720p 50 / 60 modes and make them available on the web ui.

[keremimo]

Rama: Yeah webui option would be fine if possible. Since this is all about compatibility with capture cards and since CRT monitors just stretch it into a nice 4:3 aspect, you can just leave it stretched I guess? I got my PAL Amiga and NTSC PS2 ready so if you want me to test anything on it let me know.

And again, thanks

[rama]

Latest commit adds the new 720p modes.
I've tried to do them on the same VDS clock as usual, but especially the PAL preset seems far out of spec on them.
This is going to take a while longer.

Anyway, the modes are there if you dare to try ;p

[keremimo]

Latest commit adds the new 720p modes.
I've tried to do them on the same VDS clock as usual, but especially the PAL preset seems far out of spec on them.
This is going to take a while longer.

Anyway, the modes are there if you dare to try ;p

I dared, and I liked these work much better, thanks! My capture card finally gets all the lines of PS2

I started to hate this Avermedia capture card though it refuses to capture 50hz even with the preset! Can you tell me where I can change the 50hz parameter for PAL outputs to 60hz? (I want it to pick up 50hz and output 60hz, not changing anything else) This is not a required use-case for anyone so I just want to change that for my own use. For now if I want to capture the Amiga I set it to NTSC 720p preset first, then yank the SCA cable and do a SCART switcheroo to the Amiga. Weird, I know

[rama]

You could override the mode detection.
On the serial monitor, hit "m" to disable the sync watcher.
Then load any preset you like, see if it kind of matches your input.
Presets are on "e" (NTSC default), "r" (PAL default), "9" and "2" for the 640x480 versions and "y" + "Y" for the new 720p presets.

I suspect your card just refuses one of the new presets parameters, and would work otherwise.
It could be the horizontal or vertical sync pulse position or duration.
Without the card to test, it's hard to tell.
The new PAL preset works horribly though. I get a very narrow image and my monitor can't auto format / stretch it out properly.
I can't scale the picture any more either, running into memory limitations.
It's probably a display clock that's too far off spec for 720 lines.

[rama]

Try the updated preset, it may work now

[keremimo]

You could override the mode detection.
On the serial monitor, hit "m" to disable the sync watcher.
Then load any preset you like, see if it kind of matches your input.
Presets are on "e" (NTSC default), "r" (PAL default), "9" and "2" for the 640x480 versions and "y" + "Y" for the new 720p presets.

I suspect your card just refuses one of the new presets parameters, and would work otherwise.
It could be the horizontal or vertical sync pulse position or duration.
Without the card to test, it's hard to tell.
The new PAL preset works horribly though. I get a very narrow image and my monitor can't auto format / stretch it out properly.
I can't scale the picture any more either, running into memory limitations.
It's probably a display clock that's too far off spec for 720 lines.

Memory limitations as in running out of ram on web ui? It happened so many times to me that I found a fix. Click just enough times under the memory limit, then save custom preset and reset arduino, load custom preset and keep going, watch the ram amount in serial monitor. That's how I'm managing it at least

PAL preset looks mighty fine on my end crt-wise, but then again I'm using actual PAL sources, it might be the case if you were trying NTSC signals there, I dunno?

Anyways the 720p NTSC preset works great, captures well too. My beef is with the PAL preset as always but this time I found the culprit. The horizontal frequency is supposed to be 37.5khz (My led monitor reports so when I force 1280x720 50hz on my PC) but my CRT monitor reports that the horizontal freq. on gbs-control's PAL preset is 49.9khz. If that is corrected I believe all issues including capture compatibility will be resolved. (I bet that is also the reason it doesn't display on my LED monitor either, not just capture)

NTSC Horizontal frequency is a correct number of 45khz on 720p 60hz so it captures without any issues.

[rama]

I meant GBS memory. It is used as a canvas for the ADC to draw on, and it easily fills up.
I use a multi format PSX when creating these presets, so the timing is correct for PAL and NTSC both.

The horizontal frequency issue is odd. My PC TFT reports 37KHz / 49.6Hz with a PAL PSX connected.
Are you forcing the preset by chance? The software adapts the output frequency to the source to avoid screen tear with the single buffer design.
If you force PAL on an NTSC source, it will happily upconvert the presets horizontal frequency to match the source.
You can turn this off by setting "rto->syncLockEnabled" to false in setup().

[keremimo]

I found the true culprit to be my vga-hdmi converter after doing every test possible... Sorry rama I apparently need a VGA to HDMI converter that supports 50hz for it to work. Mine apparently doesn't even support normal 1080p. Such a blunder!

The presets work well so thanks for doing them, I do have good uses for the 720p presets.

[rama]

I had to create HDMI mostly compliant presents eventually

To be honest, the picture quality is quite poor right now.
It is presentable but no comparison to the default presets with their maxed out clocks and full memory usage.
Still a lot of work to do here.

[keremimo]

By the way, this is not actually a line doubler yet right? Just upscaler still.

Any chance of a budget OSSC out of this? (Line double or quad) just the possibilities alone make this a great work!

[rama]

"240p" modes are using the built-in-hardware line doubler, so it does have that ;p

What I don't know is, whether or how the additional processing blocks may be bypassed.
There are flags that suggest that this is possible, but I haven't had any luck with them yet.
Basically, the ADC would digitize each scanline, the Input Formatter would line double them on some form of line buffer,
then it would go to the DAC for output, using the recovered H + V Sync from the source.

Anyway, you say "just" an upscaler, but this is a much more complex job than line doubling.
So chances are that the chip can do it!

[maxtherabbit]

"240p" modes are using the built-in-hardware line doubler, so it does have that ;p

What I don't know is, whether or how the additional processing blocks may be bypassed.
There are flags that suggest that this is possible, but I haven't had any luck with them yet.
Basically, the ADC would digitize each scanline, the Input Formatter would line double them on some form of line buffer,
then it would go to the DAC for output, using the recovered H + V Sync from the source.

Anyway, you say "just" an upscaler, but this is a much more complex job than line doubling.
So chances are that the chip can do it!

did I understand right that it still has 1 frame of lag in that mode? If it could line double with only a few scanlines buffered that would be beast

[rama]

Yeah, it does use a memory buffer.
The difference to other designs is that this keeps only one field in memory, which is always immediately overdrawn with new data.
The lag of the system should be 16.6ms for NTSC or 20ms for PAL sources (and not twice that, as in double buffered systems).
I have never tested the lag, but those values are under the perceivable mark for me, ie: It feels the same as a CRT.

If I ever get linedoubled passthrough working, then that'd be even better

[rama]

keremimo:
Does NTSC still work with the latest update? It looks a lot better now but I had to use more memory, which may or may not cause issues on some boards.
PAL is slightly improved as well. No memory changes there.

[keremimo]

keremimo:
Does NTSC still work with the latest update? It looks a lot better now but I had to use more memory, which may or may not cause issues on some boards.
PAL is slightly improved as well. No memory changes there.

Just updated, still works. I cannot scale horizontally either by the way. Also a weird thing happened, I changed my whole setup a little bit today, adding a CRT TV to the mix. It receives composite video through a breakout box before the signal reaches GBS. With the signal chain like this, 1280x960 looks fine, but the 720p image becomes crazy jumpy vertically for some reason. Just reporting in as feedback

[rama]

Great, the memory issue must be something very specific to some boards then.
Jumpy picture? Probably the SOG slicer level. It can be changed via terminal command "wsog x", where x is a value from 0 to 31 and 10 the default.
Try lowering it to maybe 6 or so.

Horizontal scaling is bypassed in that preset now. It's always best for quality to bypass the scaling engine, if the PLL divider and VDS clocks allow for it.

[keremimo]

Great, the memory issue must be something very specific to some boards then.
Jumpy picture? Probably the SOG slicer level. It can be changed via terminal command "wsog x", where x is a value from 0 to 31 and 10 the default.
Try lowering it to maybe 6 or so.

Horizontal scaling is bypassed in that preset now. It's always best for quality to bypass the scaling engine, if the PLL divider and VDS clocks allow for it.

Thanks! wsog 12 provided the best results among many that I've tried.

[rama]

Nice
It depends on the source, the cabling, the termination resistor (!) and even heat up from running a while.

[maxtherabbit]

last time I asked you about component out you mentioned a resistor mod to get 1Vpp output on the luma line for the -.3 sync pulse... assuming one wanted to setup one of these as a purely component video in/out device and did the mod, would it be feasible from a processor standpoint to "pass through" the video unaltered from component in to out without buffering an entire frame?

[rama]

Entirely depends on what the passthrough options allow.
For now, I'd say no.
Easy to build a bridge adapter though.

[keremimo]

Rama: The 480i images are kinda flicker-y. I see interlacing induced vertical vibrations. Is this intended or to be fixed with a de-interlacer or something like that?

Or is there a magic word I type to the serial monitor to enable de-interlacing of the rig maybe?

[ben.shinobi]

I would like to know if someone knows the difference between the GBS8200/8220 and the HD9800 V5.0 board ??
It is difficult to know this kind of information on the web...
Is the latest version works with difficult signal frequency pcb like Seibu or Irem games (57hz or 55hz) ??

[rama]

ben:
Fortunately, so far ALL GBS boards are clones of each other. They all work with this software.
You are asking about off spec video sources though. That is probably going to be an issue, because the Mode Detect unit will not be able to tell what they are.
To get them to work will require manual tweaking.
Get a board and a control chip (use an ESP8266 dev board, NodeMCU or Wemos D1), and report back.
I'll see what I can do to help out with the manual stuff.

keremimo:
I notice the interlace shaking as well but it hasn't been a priority for me so far.
It looks a bit like the effect should be less pronounced, especially if you compare different output resolutions.
Deinterlacing is possible with the chip but I have not investigated how to do it yet.
Early attempts hint at that it's going to be complicated again. It needs to use additional hardware (deactivated normally) and tons of adjustments..

[ben.shinobi]

ben:
Fortunately, so far ALL GBS boards are clones of each other. They all work with this software.
You are asking about off spec video sources though. That is probably going to be an issue, because the Mode Detect unit will not be able to tell what they are.
To get them to work will require manual tweaking.
Get a board and a control chip (use an ESP8266 dev board, NodeMCU or Wemos D1), and report back.
I'll see what I can do to help out with the manual stuff.
.

Thanks for the reply.
Few years ago, a friend lend me the gbs8200 and many of my pcb worked perfectly except few of them:
Irem M72 (R-Type, Ninja spirit...) (384*256 55hz)
Irem M62 (KungFu master) (256*256 55hz)
Toaplan Flying shark (240*320 54hz)
Seibu Raiden Fighters (240*320 54hz)
For a specific resolution and refresh rate, it seems difficult to get picture but I didnt spend too much time on it and maybe is possible to get result.
I am going to buy the CGA to VGA but before I wanted to know witch version would be better for this specific jamma pcb hardware ?

[rama]

All boards have the same basic capability, due to using the same all in one scaler IC.
They differ a little in the passive components, mainly for cost reduction.
If you're buying new, I'd go for a generic board that looks to be "the original".
Black push buttons, orange pots, recognizable brand on the SDRAM, power input section with 2 diodes and a "470" coil.
https://www.ebay.de/itm/SODIAL-R-GBS820 ... 2718345439
(Wow, down to 15 Euros incl. shipping!)

What it does out of the box is a bit of a gamble. The software that it ships with either likes your Jamma boards, or it doesn't.
However, if you override the software with this project, all the options of the scaler IC are possible.
It can work with all your boards just fine, but it needs someone to dial in the parameters (mostly my job ;p).

[ben.shinobi]

Ok I'm going to buy it and will get back in the next few days for feedback.
However, my project is not to use LCD but only for recording gameplay.
What kind of capture video card I need ? If you have any advices for this ?
Elgato capture box would be enough or do I need Startech PEXHDCAP ?

[rama]

I don't own any, unfortunately.
Best if you comb through this thread a bit and find people that use capture cards, then ask them for advice.
(I heard the PEXHDCAP is good, and others mostly not.)

[keremimo]

Ok I'm going to buy it and will get back in the next few days for feedback.
However, my project is not to use LCD but only for recording gameplay.
What kind of capture video card I need ? If you have any advices for this ?
Elgato capture box would be enough or do I need Startech PEXHDCAP ?

Avermedia live gamer hd user here. I definitely recommend you get pexhdcap. Elgato won't support 1280x960 that the custom firmware produces, 720p still in development.