MiST VGA upscaling experiments

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Re: MiST VGA upscaling experiments

Postby SuperBabyHix » Mon Feb 27, 2017 5:08 pm

Sorgelig wrote:SuperBabyHix,
It's true that many (if not all) cores output slightly out of TV standard freqs. Real PAL resolution is 312.5lines per field. I don't remember any core providing exactly 312.5lines(may be only Minimig - but i didn't check its code as it's too complicated). So if core provides only 312lines or even 320lines - the vertical frequency is already doesn't match to standard PAL. So, you will have stutter issue if you will output to PAL. I suggest to set scaler output to 60Hz(NTSC). Stutter will be less noticeable.


I will give that a shot. Thanks for the info.

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Re: MiST VGA upscaling experiments

Postby mambrino » Wed Mar 08, 2017 5:14 pm

Sorgelig wrote:LKV353 accepts scandoubled RGBHV (48Hz/50Hz) video through VGA input. Although sometimes it's not well centered.

But can you see the whole picture? I have the GBS8200 scandoubler and (at least in my TV) the image is shifted down aprox. 20-30px (plus border) and GBS8200 has no position adjustment for VGA input.

Thanks ;)

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Re: MiST VGA upscaling experiments

Postby Sorgelig » Wed Mar 08, 2017 10:28 pm

Yes, i can see the whole pic. But i didn't test all cores. Only those on my repository.

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Re: MiST VGA upscaling experiments

Postby DrOG » Sun Sep 24, 2017 3:02 pm

Hi!

My cheap chinese upscaler arrived at friday, here are my first impressions, and some screenshots (taken from my Samsung LE40B650 TV's framebuffer using ScreenCap SamyGo application, as usually).

Didn't test all the cores so far, perhaps never will (there are more than 60 if we count the arcades also, and some of them has 6 video output modes: PAL and NTSC systems, all with VGA, SCART and Component).

If you are interested in something sepcific question not discussed below, I'll try it in 1-2 days and share my results in this topic, don't hesitate to ask!

First of all, it's not an "original" Gonbes product, it seems to be a GBS-8220 without the second VGA output. Perhaps it's a clone of a clone, but paying attention it's price (18$ with shipping), it was a bargain.

The panel says it's a "HC-V3.5", whatever it means.
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It came in an antistatic bag, with a power cable, and nothing more. It has a VGA and an YPbPr input, no SCART - but we don't need it! If you want to built a SCART female->VGA male adapter, you can solder one using the schematic as follows:

VGA_SCART_function
1-------15-------RED
2-------11------GREEN
3--------7-------BLUE
5-------17-------GND
6-------13------R GND
7--------9------G GND
8--------5------B GND
10------18-------GND
13------20-----C SYNC

Or if you want to use a sync separator/stripper (i.e. LM1881 IC), here is a decription how to do that:

http://www.theisozone.com/forum/viewtop ... 20&t=47226

For us, who use this with an FPGA (i.e. MiST), there's no reason to do so: we have a pure CSYNC in scandoubler disabled mode on VGA pin 13, so a regular VGA cable is fine for the job.

On the board the S (composite sync) and the HS (horizontal sync) pins are joint, I verified it with a multimeter.

You can cycle between RGBHV-RGBS-YPbPr pressing the 'left' button.

In the scaler's 'Picture' menu I didn't adjust the Brightness, Contrast, Saturation or the R, G, B potentiometers on the board. I adjusted the Geometry in RGBS mode, and the 'Sharpness' in case of RGBS and YPbPr input. On the TV I used the same setting for every input, and adjusted geometry to bring out the best possible result.

So here are my experiences:

1.) I used a noname MOLEX PSU, shipped with my Logilink USB to IDE/SATA adapter to feed the board.
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It was powerful enough, the panel says all voltages between 5-18V should be fine.

2.) The Menu's language was chinese by default, but it's not too difficult to change to english. You can adjust a couple of things, but not the geometry if you have an RGBHV or YPbPr input (only in case of RGBS signal is the 'Geometry' submenu active).
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I have chosen the 1024x768 resolution from the 'Display' submenu (it's still lower than the physical panel size of my LCD TV/monitors).

3.)/A.) The Atari ST core works in both RGBHV and RGBS mode using US TOS (NTSC standard), and in RGBHV mode with UK TOS (PAL standard).
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/B.) In RGBS and YPbPr mode you can set the 'Sharpness' parameter found in the 'Picture' submenu. In RGBHS mode this does not have any effect on the picture quality.
It's in the range of 0 to 10, I recommend to use a value near 3 (see 3.)/A.)).
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/C.) In PAL RGBS mode the picture is unusable, it scrolls, freezes or the result is a black screen:
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/D.) In 'Mono' mode the picture was corrupted also.
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4.) Most PAL cores' RGBHV video is distorted, and the bottom 20% of the picture is missing (compared to my TV's SCART input in scandoubler disabled mode).
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This is a big problem because in this mode the Geometry menu is unavailable.
Unfortunately in most cases the PAL RGBS mode is not a working solution either (see 3./C.)).

5.) In some cores' RGBS (scandoubler disabled) mode there's a glitch at the top of the screen (C64 PAL mode and NES (NTSC) core):
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6.) If the given core supports YPbPr out (see Amiga AGA/minimig), it's a good alternative, as the picture is usually not distorted, and the sharpness can be set manually.
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7.) The board's scaler gives a bit blurry, but much smoother and less distorted picture compared to my TV: looks like it uses a more sophisticated resize algorithm (i.e. bilinear filtering instead of nearest neighbor). See the MSX core:
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8.) If you find an input signal compatible with the upscaler, you can connect it's VGA output to the Mini VGA to HDMI converter, and use it via your TV's/Monitors HDMI input.
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9.) So far I didn't found any serious artifacts (waves or 'snow'), although tried only still images so far. Will test later the smoothness of scrolling and the latency during games.

10.) If you have a very non-standard core, the upscaler wont't work with it (tried i.e. the Bashkiria-2M beta from Gehstock, the result was black screen).

CONCLUSIONS:
1.) The efficiency of this scaler depends wholesale on the given core: If it's a PAL-only core without YPbPr output option, there's only a little chance that it will work.
2.) Compared to the low price, it can be a cost-effective solution.
3.) This device would be much more useful if the 'Geometry' option could be activated in RGBHV mode. Another solution would be the transplantation of Atari ST core's 'Video adjust' menu to the firmware, but I think it's not so easy.

To be continued (perhaps)...

Gábor

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Re: MiST VGA upscaling experiments

Postby ericgus » Mon Sep 25, 2017 5:21 am

DrOG wrote:Hi!
CONCLUSIONS:
1.) The efficiency of this scaler depends wholesale on the given core: If it's a PAL-only core without YPbPr output option, there's only a little chance that it will work.
2.) Compared to the low price, it can be a cost-effective solution.
3.) This device would be much more useful if the 'Geometry' option could be activated in RGBHV mode. Another solution would be the transplantation of Atari ST core's 'Video adjust' menu to the firmware, but I think it's not so easy.

To be continued (perhaps)...

Gábor


Would be interesting to see your results under NTSC..

I use one of these on one of my Amigas and it works fine .. the trick with these generic GBS boards is to get one with Samsung ram .. they seem less prone to "sparkles" on the output .. That said I have not tried mine directly connected to the MiST .. additionally these boards seem very sensitive to the power supply quality and how noisy it is.. (I think the psu you used for your tests is probably one of the better options)..

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Re: MiST VGA upscaling experiments

Postby DrOG » Mon Sep 25, 2017 12:40 pm

In general NTSC cores are less problematic compared to PAL.
The NTSC standard contains 480 lines, same as the VGA vertical resolution, and the frame rate (59/60Hz) is near the same as well.

Here are some screenshot taken from cores with NTSC mode:

Minimig (from Turbo Chameleon 64):
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NES:
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C64:
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I didn't notice any noise on the video, so I think my PSU is OK.

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Re: MiST VGA upscaling experiments

Postby eeun » Tue Sep 26, 2017 3:59 pm

DrOG, have you come across this? It seems on par with the work you're doing with the GBS board and MiST, but replacing the GBS on-screen controller with a Raspberry Pi for better control:

https://shmups.system11.org/viewtopic.php?f=6&t=52172
https://github.com/dooklink/gbs-control

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Re: MiST VGA upscaling experiments

Postby DrOG » Tue Sep 26, 2017 4:42 pm

Yes, I saw it, but didn't try so far. I decided to test all the cores during the next days, and share my experiences, perhaps will make a 'compatibility list'. After that perhaps will try the above linked method.

At least one PAL core, the Apogee BK-01 is perfect over RGBHV and RGBS, and has the opportunity to set the video's position on the screen pressing 'Alt' + arrow keys. I don't know how difficult it would be to implement the same feature on firmware level instead of core, but it would be very useful! Some cores' video output is badly centered, but most PAL core has borders, so moving upwards the picture the whole game area would fit into the screen, and maybe even the distortion could be compensated switching the monitor's AR from 4:3 to 16:9.

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Re: MiST VGA upscaling experiments

Postby DrOG » Sat Sep 30, 2017 7:21 am

Hi All!

Here are the results of my experiences, a 'compatibility list'. I made some new screenshots also. See attachment.
Image

legend:
OK=works without major issues
0=not working
g=graphic glitches
c=badly centered (left side of the picture is missing)
t=trunctated (the bottom of the picture is missing)
f=feculent
b=black/blank screen
-=n/a
*=notes/comments, as follows:

1. The Acorn Electron has a menu option to switch between PAL and NTSC, but it seems that does not work.

2. Apogee BK-01 is a special core: not trunctated over RGBHV despite the PAL video standard, fine over RGBS and positionable with Alt+arrow key combos.
Image
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3. Atari ST is another user-friendly core: works over RGBHV in PAL mode, and positionable using the menu.

4. The C16/Plus4, Videopac/Odyssey2 and Apple ][+'s picture is badly centered/trunctated over RGBHV in NTSC mode:
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5. The C64 core in PAL standard outputs a glitchy picture over RGBS, the NTSC-only NES core shows the same phenomenon. After pressing the 'down' (Auto) button on the scaler, in the first case the picture goes black, int the second case the glitch disappears.

6. A few PAL cores are fine over YPbPr: Amiga and Elektronika BK0011M.
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7. Gameboy core is trunctated over RGBHV.
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8. Hungarian home computers are fine over RGBHV despite the PAL standard, as they are not scandoubled cores, because joco, the developer applied a trick to make them VGA-compatible:
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Here's how he did it, perhaps it's useful for other core developers as well:
http://www.joco.homeserver.hu/fpga/mist_primo_en.html
http://www.joco.homeserver.hu/fpga/mist_ht1080z_en.html
http://www.joco.homeserver.hu/fpga/mist_tvc_en.html

9. The known-to-be-problematic PC Engine core is just fine for this scaler:
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10. The ZX-81 core is OK in PAL and NTSC modes despite the small graphic glitch not only in RGBHV, but in RGBS mode also.
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Arcade cores:
Most 640x480@60Hz cores are working fine in RGBHV mode, no YPbPr or RGBS:
Asteroids, Cosmic Avenger, Donkey Kong, Dorodon, Frogger, Ladybug.

Some of them are badly centered or trunctated:
Galaxian, Scramble.
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800x600 cores' video is mostly trunctated over RGBHV, no YPbPr or RGBS:
Crazy Kong, Moon Patrol, Pengo, Space Attack, Space Invaders, Space Laser, Super Earth Invasion.
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Some exception (no trunctated over RGBHS):
Galaxy Wars, Invaders pt.2, Lunar Rescue, Pacman.

Sorgelig's 640x480 cores are universal, and work in RGBHV, YPbPr and RGBS as well:
Galaga HQ2X, Phoenix.
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The newest beta, Gehstock's River Raid is incompatible with the upscaler.

My board has a Micron Technology RAM: MT 48LC2M32B2, no Samsung or Hynix.

If anyone has a specific question, let me know!

Have a nice weekend: Gábor
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Last edited by DrOG on Sun Oct 01, 2017 4:14 am, edited 1 time in total.

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Re: MiST VGA upscaling experiments

Postby Gehstock » Sat Sep 30, 2017 11:43 am

Thank You
Not only my Cores for Mist : https://github.com/Gehstock/Mist_Cores
My Cores for Mister : https://github.com/Gehstock/Mister

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Re: MiST VGA upscaling experiments

Postby ericgus » Sat Sep 30, 2017 9:33 pm

I see you dont have the PlusTOO core in that matrix.. its also notoriously fussy. Right up there with the AtariST core.

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Re: MiST VGA upscaling experiments

Postby DrOG » Sun Oct 01, 2017 4:56 am

ericgus wrote:I see you dont have the PlusTOO core in that matrix.. its also notoriously fussy. Right up there with the AtariST core.

PlusTOO is on the list as 'Apple Macintosh'.

I found some inaccuracy, but corrected them:

1.) The Sharp MZ-80K is NTSC core of course, and not PAL.

2.) Apple ][+'s picture is trunctated over RGBHV.

3.) Left out the River Raid beta, which is uncompatible with the scaler.

Found some issues also, would be nice if someone else could try them and report back, if they are real bugs, or the fault is in my device:

1.) Was unable to load .BINs with the Videopac/Odissey2 core. As I remeber, it worked earlyer, but not sure (was a long time ago I tested it).

2.) Tried to switch my minimig core from PAL to NTSC, but after reset it still booted in PAL mode (I use the last, 1.2.2 beta version). That's why is missing the NTSC system's YPbPr rubric: could not test it, as my MiST minimig core stuck in PAL. Made the trials with the Turbo Chameleon's minimig core, which does not have YPbPr option.

3.) I cheated a bit with the Videoton core: the public VGA version has a 800x600 RGBHV output, which is trunctated if used with the upscaler. I have an earlier beta, which's VGA resolution is 640x480@60Hz, but the menu is buggy by me (the author says it's fine on his MiST). I used this version to make the screenshot. If anyone is interested and the developer agrees I can upload this version of the core to the forum.

CONCLUSIONS (again):

1.) The lower the resolution, the greater chance of success! Made some statistics, and I fount if you are using 640x480@60Hz, approx. 75% of the cases will work. Using 720x576 or 800x600, you have approx. 25% chance that the board will accept the signal. Over it (1024x768 or above) none of the cores worked (there are only 2 candidates, the PlusTOO and the River Raid beta).

2.) Don't forget, that this is an UPSCALER, designed to process CGA/EGA arcade signals! We shouldn't expect to handle non-computer standards, i.e. PAL sources flawlessly.

3.) If you have an already VGA-compatible output (in most cases 640x480 or 800x600), why use another box? I think the best is the direct connection between devices (VGA or SCART).

4.) I'm now studying thoroughly the option to use a Raspberry Pi to control the board:
https://shmups.system11.org/viewtopic.php?f=6&t=52172
https://github.com/dooklink/gbs-control
As I see it now, it doesn't worth the hassle, one more gadget on the table is absolutely unnecessary. I have a Pi, and use it with RetroPie. It has a HDMI output, which is compatible with the newer TVs/monitors already, so I can run on it that I want, and connect to the screen using only 1 cable.

5.) I think the potential of the device is not fully utilized, a custom firmware would be welcomed, to be able to set the geometry in case of RGBHV input at least.

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Re: MiST VGA upscaling experiments

Postby ericgus » Sun Oct 01, 2017 5:16 am

DrOG wrote:
ericgus wrote:I see you dont have the PlusTOO core in that matrix.. its also notoriously fussy. Right up there with the AtariST core.

PlusTOO is on the list as 'Apple Macintosh'.
.


Oh indeed it is! ..

Thank you for doing this exhaustive research .. I actually have a second board here and was going to try it out with a few cores but have never been able to get the time to do it.. your work goes well beyond that!! ,, Amazing ..

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Re: MiST VGA upscaling experiments

Postby DrOG » Mon Oct 02, 2017 4:35 am

Hi!

This board doesn't like framerates over 60Hz, and separated Hsync and Vsync in case of interlaced (15 kHz) signals. In this case only RGBS (Csync) works.

Some further results, but this is off-topic, as it has nothing to do with MiST:

Tried the board with my old Yamada DVX-6700 standalone DVD-player & LM1881 sync stripper in RGBS mode. It was fine using NTSC system:
Image

For reference, the same over SCART, without sync stripper:
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Using PAL standard the same garbage on screen as in case of some cores in PAL mode (minimig, Atari 2600, Atari ST, Elektronika BK0011M and Videoton TVC):
Image

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Re: MiST VGA upscaling experiments

Postby SuperBabyHix » Mon Oct 02, 2017 2:10 pm

Thanks a bunch for testing all that. I really appreciate it.

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Re: MiST VGA upscaling experiments

Postby DrOG » Mon Oct 02, 2017 2:34 pm

SuperBabyHix wrote:Thanks a bunch for testing all that. I really appreciate it.

You're welcome! It was a bit boring and monotone to test all the cores, but the results may help to decide if you are hesitating to buy this (or similar cheap chinese) upscaler board.


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