MiST VGA upscaling experiments

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Re: MiST VGA upscaling experiments

Postby Newsdee » Tue Feb 17, 2015 11:07 pm

DrChaos wrote:BTW: Unrelated, but may be of interest for some people - in the German a1k forum someone has posted a simple mod to reduce the pixel noise of the GBS8200/8220 : http://www.a1k.org/forum/showthread.php?t=48076&highlight=GBS


It interests me :-) The RGBHV handling seems clean from my tests yesterday, but RGBS (which I use it with my Neogeo MVS) was always slightly noisy. Could I ask if you can send me a translation of the mod and the pictures he has?
(I can't open them, and Google translate isn't that good for technical stuff...)

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Re: MiST VGA upscaling experiments

Postby DrChaos » Tue Feb 17, 2015 11:28 pm

Well, that is very simple :D
Just tape aluminium foil at the back of the board. Some used double sided tape, others used two single layers of normal tape with Aluminium foil between the two layers. The guy who posted first used copper. I used normal tape, but realised that I did not have that issue, or did not notice, because my issues came from a 1.5a power supply and dissapeared after using 2a.
Just give it a try. Some report that they are able to reproduce the effect by removing the foil and it can't hurt, just make sure that the aluminium foil is not connected to the board.

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Re: MiST VGA upscaling experiments

Postby Newsdee » Wed Feb 18, 2015 12:01 am

How big does the strip need to be?

Fortunately RGBHV input seems solid so not so much a problem for the MiST. I have to try to upload some videos to YouTube to see how the resolution is handled.

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Re: MiST VGA upscaling experiments

Postby Gryzor » Wed Feb 18, 2015 7:39 am

Thanks so much for the reply; I've seen it in a few places, was just asking to see if you had found a better price (not that it's that expensive, but anyhow) :)

I'll get reading right away!

How exactly did you connect it?

Thanks again, much appreciated!
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Re: MiST VGA upscaling experiments

Postby DrChaos » Wed Feb 18, 2015 8:41 am

There is no exact size. It should cover the connection between the converter IC and RAM, because this connection seems to be responsible for the noise. Just try it, it's easy to remove :)

Unfortunately the GBS is not a solution for most PAL cores, because the picture of these cores are too much off center. (This, btw, is also true for the AGA Core in NTSC and PAL as far as I can see). The Geometry options do not work in GBS VGA.The NTSC Cores also work with scart2vga on my TV, although the picture is better with GBS. I'll try the scandoubler off with the RGB input (P11) soon, although I think that will not solve my issues with the C64 core, because it is not available in 15Hz...But it may be possible to use input p11 to have a more universal input for the mist, because it should handle a wider range of inputs and switching by the "SW" button could be possible.

My hope is the CFW for the GBS, one clever guy found out how to program the gbs with a raspberry - I'll try that when I get the pinheader connections:

http://shmups.system11.org/viewtopic.php?f=6&t=52172

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Re: MiST VGA upscaling experiments

Postby MasterOfGizmo » Wed Feb 18, 2015 11:47 am

I am currently rewriting major parts of the Atari ST core video system. Major goal is to have the san doubler optional.

Here's a first screenshot of the Atari core running on a regular TV using a Minimig-VGA-Scart cable.

mist_atari_tv.jpg


This still needs some tweaking as you can see the image is not centered. Also the 1280x1024 Viking mode is currently not working anymore and the OSD also has small issues. But once that's all ironed out the Atari ST can be run on a TV just like the Amiga core as well.
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Re: MiST VGA upscaling experiments

Postby Newsdee » Wed Feb 18, 2015 2:03 pm

Gryzor wrote:How exactly did you connect it?


An image is worth a thousand words :D Both cards are connected together with a VGA gender changer (warning: many cheap ones turn the connector upside down). VGA in is at the bottom, VGA out is from the SLG-3000:
Image

Both boards share the same power supply by connecting the SLG via this connector on the right.
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Re: MiST VGA upscaling experiments

Postby Newsdee » Wed Feb 18, 2015 2:43 pm

DrChaos wrote:My hope is the CFW for the GBS, one clever guy found out how to program the gbs with a raspberry - I'll try that when I get the pinheader connections:
http://shmups.system11.org/viewtopic.php?f=6&t=52172


The link on that page is a treasure trove of information... video timings, data sheets for the GBS components... anything one would need to rebuild one in HDL, if it wasn't for the massive upscaler chip that does the heavy lifting :D Judging by how complex it is, I guess we're not going to see an open-source HDL implementation of an upscaler anytime soon...

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Re: MiST VGA upscaling experiments

Postby Newsdee » Wed Feb 18, 2015 3:36 pm

MasterOfGizmo wrote:Also the 1280x1024 Viking mode is currently not working anymore


I wouldn't think that works over SCART? Doesn't it have to be 240p60 or 288p50?

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Re: MiST VGA upscaling experiments

Postby MasterOfGizmo » Wed Feb 18, 2015 7:47 pm

Newsdee wrote:
MasterOfGizmo wrote:Also the 1280x1024 Viking mode is currently not working anymore


I wouldn't think that works over SCART? Doesn't it have to be 240p60 or 288p50?


The high resolutions (incl normal st high) are not supposed to work over scart. But the changes in the video setup were pretty fundamental and also affected the viking mode. Now it's working again. I'll release a test core soon, so you can test whether something broke that used to work and of course to test the 15khz mode.
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Re: MiST VGA upscaling experiments

Postby Gryzor » Thu Feb 19, 2015 8:38 am

Newsdee wrote:
Gryzor wrote:How exactly did you connect it?


An image is worth a thousand words :D Both cards are connected together with a VGA gender changer (warning: many cheap ones turn the connector upside down). VGA in is at the bottom, VGA out is from the SLG-3000:

Thanks for the pics mate! I wonder if I can fit all that in the mod I have in mind...
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Re: MiST VGA upscaling experiments

Postby DrChaos » Thu Feb 19, 2015 8:59 am

Newsdee wrote:WOW!! The Gonbes turns out to work quite nicely!
It doesn't work with scandoubler disabled (expects 480p on RGBHV) and not all cores work (some show an image off centre)


After I read your post I soldered a vga2rgb cable to use the P11 input, that does not solve the "off center problem", but worked with the Atari core (by switching the input on the GBS to RGB) - after I tested that I noticed that 15Hz is also working via VGA input, at least it worked with the Atari 800 RGB core. I hope I can try the 15hz AGA this evening.

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Re: MiST VGA upscaling experiments

Postby DrChaos » Fri Feb 20, 2015 10:23 pm

Hey Newsdee,
I think it's time to change your first post and the WIKI again ;)
I just tested the 15kHz by disabeling the scandoubler for the AGA Core, it works as expected with the GBS when switching the input to RGBS. However, with standard setting my image is better using the VGA2Scart cable on my SyncMaster TA350. Haven't tested my LG yet.
My SyncMaster 730BF is working out of the box in all 31kHz cores, BTW.

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Re: MiST VGA upscaling experiments

Postby eeun » Fri Feb 20, 2015 11:48 pm

All I've attempted so far is to run the ST core through the 8220's VGA port at 15kHz. It works fine and looks like it does in the core's doubled mode, but with a softer focus. Picture is slightly off-centre, but only by about 1/2" on a 17" LCD.
I am still getting that ghosting around the mouse pointer that's always been an issue with my 8220 and a real ST, but the picture is much more stable than I was able to achieve with a real ST.

FYI my 8220 is ver 3.0, all settings default.

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Re: MiST VGA upscaling experiments

Postby DrChaos » Sat Feb 21, 2015 7:19 pm

Is the new Atari core with 15kHz already available? I can test that, although I am not much into Atari ST...

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Re: MiST VGA upscaling experiments

Postby eeun » Sat Feb 21, 2015 8:26 pm

Yep, r800 here.

I created the mist.ini file below in my SD root (and as mentioned elsewhere, make sure there's a carriage return after the last line), and it just works.

Code: Select all

[mist]
scandoubler_disable=1

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Re: MiST VGA upscaling experiments

Postby NML32 » Sat Feb 21, 2015 10:48 pm

Weird, I can't get it to switch to 15Khz. I'm running the latest firmware and have the mist.ini file in the root of the SD card. I even place a CR after each line even the last line. I wonder what I'm doing wrong?

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Re: MiST VGA upscaling experiments

Postby Newsdee » Sun Feb 22, 2015 12:54 am

Make sure you have the latest firmware and the latest AGA core, it won't work without that.

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Re: MiST VGA upscaling experiments

Postby ryan » Sun Feb 22, 2015 3:42 pm

This thread is long and winding and I haven't followed it fully so this might be repeated info, but just thought I'd mention I just tried the Monoprice 106191 VGA to HDMI Converter with my MiST with both the ST and Amiga core and it seems to work. I haven't tested extensively but i had ST low res EmuTOS desktop and a couple of Amiga games (Nebulus and Speedball 2) up on my big screen LCD TV a second ago.

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Re: MiST VGA upscaling experiments

Postby Newsdee » Mon Feb 23, 2015 1:33 am

(removed dupe post)
Last edited by Newsdee on Mon Feb 23, 2015 1:37 am, edited 1 time in total.

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Re: MiST VGA upscaling experiments

Postby Newsdee » Mon Feb 23, 2015 1:35 am

ryan wrote:Monoprice 106191 VGA to HDMI Converter


If you can test other cores (NES, C64) I can add it to the list of upscalers in my spreadsheet.

Would know know what upscaler chip it uses?
I have a couple of similar boxes but results weren't good with the old Amiga core (pre-AGA) or the others I've tried.

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Re: MiST VGA upscaling experiments

Postby MasterOfGizmo » Tue Mar 03, 2015 10:31 am

The latest core in the beta folder now also supports the "video adjust" feature when in 15khz TV mode. This allows to center the image nicely on a TV connected via a VGA to SCART cable. Makes playing Atari ST games on a TV really fun ...

Furthermore the system clock precision has been increased and it's now exactly 8Mhz (before it was 7.96875 MHz) resulting in a video timing slightly closer to a real ST.

One thing i'll fix asap is the main game screen of StarDust which flickers badly as the game tries to open the top and bottom borders in a slightly different way than e.g. Obsession Pinball or Pacmania STE (which both work fine).
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Re: MiST VGA upscaling experiments

Postby DrChaos » Tue Mar 03, 2015 1:18 pm

That sounds great. Would love to see this implemented in the C64 core...

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Re: MiST VGA upscaling experiments

Postby johey » Fri Jun 05, 2015 7:46 am

Just want to confirm here... Are you using the XRGB Mini with the NES core? I can't seem to get it working. I have a passive Minimig VGA-SCART cable and it works great with the Amiga core with the XRGB Mini, given that I disable the scandoubler. Otherwise the Mini says NO INPUT.

The NES core however does not seem to obey the scandoubler setting. Can I enforce it in some way or how do you make it work? Or better, can you in some way get the XRGB Mini to accept 31 kHz RGB input?

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Re: MiST VGA upscaling experiments

Postby Newsdee » Fri Jun 05, 2015 1:11 pm

Right, the NES core does not use the scandoubler setting so always outputs 31khz. It works for me but only because I have an UMSA from ArcadeForge to convert the RGBHV of VGA into more standard RGB + Sync. It is still at 31 khz but it works.

I actually have the opposite problem, I bought a VGA to SCART cable but couldn't get it to work with the Amiga core. I guess the minimig cable might be wired in a particular way.


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