VOGONS


VGA Capture Thread

Topic actions

Reply 1280 of 1403, by imi

User metadata
Rank l33t
Rank
l33t

the adsp makes it so the datapath card locks onto the signal correctly, while it's possible to shift the image on some of the extron interfaces that's not really necessary, you can just position it correctly in VCS using the interface.

Reply 1281 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member
imi wrote on 2023-03-01, 03:22:

the adsp makes it so the datapath card locks onto the signal correctly, while it's possible to shift the image on some of the extron interfaces that's not really necessary, you can just position it correctly in VCS using the interface.

Ah, alright. But can you tell me which model you use? For example the page says that the feature was introduced with 200Rxi series which "solve almost any sync related problem" and then goes on, saying that it's also implemented in RGB 109xi which seems to make no sense. RGB 109xi however is much cheaper. I mean possible it's just a "dumbed down" version (Like what the amiga 500 is to the amiga 1000)

Edit: Ordered 109xi now, hope it works 😀

Reply 1282 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member
Great Hierophant wrote on 2023-02-28, 23:40:

The Datapath has a known bug in that at 640x480 @ 59.94Hz it will not display the bottom 2-3 lines correctly. The solution that worked for me was to set the refresh rate to 75Hz in Windows. Obviously that will not work in pure DOS but I am sure there is some solution which allows you to change the refresh rate, maybe to 70Hz.

Checked in Windows now. No idea how you can force a Refresh rate on a DOS game, but even the refresh rate in Windows doesnt change anything. Ran Windows 640x480 in 70Hz and 75Hz, and the same issue occurs. So I am hoping for the adsp now imi recommended.

Reply 1283 of 1403, by imi

User metadata
Rank l33t
Rank
l33t

I also had the issue in windows and even 800x600 (though to a lesser degree)
but yeah, as I wrote in my original post I'm using a 160xi, though it doesn't really matter as long as it has ADSP
though I have others too, 109xi should work just fine.

the 200Rxi is an older series iirc but yeah I get why that naming is confusing ^^

Reply 1285 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member
imi wrote on 2023-03-01, 13:55:
I also had the issue in windows and even 800x600 (though to a lesser degree) but yeah, as I wrote in my original post I'm using […]
Show full quote

I also had the issue in windows and even 800x600 (though to a lesser degree)
but yeah, as I wrote in my original post I'm using a 160xi, though it doesn't really matter as long as it has ADSP
though I have others too, 109xi should work just fine.

the 200Rxi is an older series iirc but yeah I get why that naming is confusing ^^

I got the 109xi now but either it doesn't work, or I am doing something wrong.
I got the VGA In connected to my DOS PC. And the "Buffered Local Monitor Output" connected to my Monitor and Capture card.
The Signal looks exactly like it did before, and no matter which switches I use or which whether I use the Horizontal Shift Knob, nothing seems to change. Tested all the settings I could think of, but nothing changes, can't even screw up the signal. So to me it looks like the VGA Out is just a passthrough.

I guess I am supposed to use the BNC out connections and put them back into VGA like with this one?
https://www.amazon.com/StarTech-com-6-Feet-Co … x-Monitor-Cable

Reply 1286 of 1403, by imi

User metadata
Rank l33t
Rank
l33t

the buffered local monitor ouput is just that, it just hands through the signal from the input in case you also want to view it on a monitor, you need to use the RGB output via a BNC to VGA cable for capture yes.

Reply 1289 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member

Received the cables today and tested the 109xi, works like a charm. Unfortunately the 640x480 resolution still stays a hassle. Only get a clear picture with 800 width and that is not automatically applying due to a bug in VCS I guess (posted in the other thread).
Furthermore I think that about 2 pixels are missing from the width. If I overwrite the 640x480 resolution to 642x480 I get everything, but ofc that turns scaling into more of a problem. If I just change the screen width to adjust, I don't get a sharp picture due to phase.

As it seems like VCS will not receive anymore fixes (until someone else has the will and expertise to continue it) I basically created two compromise solutions now:
640x480 with 800 width screen size. This needs to applied manually. It's missing a few pixels in the width but it results in a clean picture (not sure how exactly as in theory one or two pixels need to be stretched)
640x480 with 801 width screen size. This is basically my "fallback" setting which automatically gets active. Left and right side arent perfectly sharp as the phase isn't fitting. But its better than nothing.

Furthermore I also realized that the signal isn't 100% stable if you touch the cables. These BNC connectors aren't the greatest. I mean usually you don't touch them again, but still (these were new ones).

So overall, the Datapath Vision RGB might be the best capturing device, but it still brings a bunch of problems and is far from perfect as well.

Reply 1290 of 1403, by imi

User metadata
Rank l33t
Rank
l33t

800 width is normal for 640x480, you gotta take into account that the "width" in that case is the sampling of the entire VGA signal line, not the output resolution of the PC itself, if it's missing pixels in the width that should be solvable just by horizontal position in VCS, if that doesn't help try the H-shift on the extron maybe to get more leeway

the automatic switching doesn't work for me all the time either, I just saved presets for each machine and access the different capture resolutions with keyboard shortcuts when needed.
most of my BNC cables are old and used, maybe they used to be better quality back then 😁

Reply 1291 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member
imi wrote on 2023-03-09, 23:30:

800 width is normal for 640x480, if it's missing pixels in the width that should be solvable just by horizontal position in VCS, if that doesn't help try the H-shift on the extron maybe to get more leeway

the automatic switching doesn't work for me all the time either, I just saved presets for each machine and access the different capture resolutions with keyboard shortcuts when needed.
most of my BNC cables are old and used, maybe they used to be better quality back then 😁

That H Shift on the Extron has exactly the same effect as the shift in VCS, doesnt make a difference. And of course it then moves the other side out of screen.
In fact that "missing pixel" is actually introduced by the Extron as it seems like it just slightly changes the phase.
So without the Extron you can have it centered. With the Extron you either have the left border out of screen, the right border out of screen (if you use horizontal adjust on VCS or the Hardware). The only way to get it centered is to change the phase shift and make it look unsharp, or to increase the resolution to 642x480 (because 641x480 doesnt work in VCS) via an alias. So in theory I guess you could also use 642x480 and then "downscale" it to 480...didnt test that. But it would also add one additional step, and no matter what I would need the 800 screen size which doesnt change automatically.
The Hotkey function also doesnt work for me. With 2 settings saved, none of them active, both set to hotkey activation (CTRL+F1, CTRL+F2), it never switches. Hotkey just doesnt work, using it version 2.6.0 on Windows.
For testing speedsys is great as it has this bars on either side.

Without the Extron:

Ohne hardware.png
Filename
Ohne hardware.png
File size
58.88 KiB
Views
1555 views
File license
Public domain

With the Extron:

WithHardware.png
Filename
WithHardware.png
File size
87.94 KiB
Views
1555 views
File license
Public domain

With the Extron changed width to 797

797.png
Filename
797.png
File size
85.79 KiB
Views
1555 views
File license
Public domain

You can see that only the first one actually has a complete pic in good quality.

Reply 1292 of 1403, by imi

User metadata
Rank l33t
Rank
l33t

you can try playing around with the H-shift on the extron and play with the phase in VCS until you get it just right
changing the width will always result in a soft image at one part as the sampling itself is off.

Reply 1293 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member

Yeah, but you suggested that in your last post however, and I already replied, that it has exactly the same effect as changing the horizontal position on the hardware. It basically jumps too far - on both options.

Reply 1294 of 1403, by imi

User metadata
Rank l33t
Rank
l33t

for me the H-shift sometimes has a slightly different effect, you need to keep in mind that the extron is doing the shift in the signal, while VCS is doing it after the capture so there may be phase differences depending on where the active part of the signal moves, so moving in VCS doesn't change anything on the signal but just the positioning in the capture window.
sometimes I have to completely invert the phase in VCS though as like you said the extron sometimes influences the phase and makes it move 1 pixel by the phase being the other way.

the way your picture looks like to me is like the phase is off, other than that idk what else to do, sorry 😒

Reply 1295 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member
imi wrote on 2023-03-11, 15:04:

for me the H-shift sometimes has a slightly different effect, you need to keep in mind that the extron is doing the shift in the signal, while VCS is doing it after the capture so there may be phase differences depending on where the active part of the signal moves, so moving in VCS doesn't change anything on the signal but just the positioning in the capture window.
sometimes I have to completely invert the phase in VCS though as like you said the extron sometimes influences the phase and makes it move 1 pixel by the phase being the other way.

the way your picture looks like to me is like the phase is off, other than that idk what else to do, sorry 😒

I made a demonstration:
https://youtu.be/M1WhsWmNGKc

The Extron is widen the Horizontal Picture by about an equivalent of about 1-2 pixels.
It's fixing the vertical size, but not completely. 1 Pixel or so is still missing.

I demonstrated what happens if you adjust the horizontal position with vcs and what happens if you use the extron (same difference, either side is always outside of the screen)
You can also see that the bottom line is never showing as its always cut off (with and without extron).
I also changed the phase setting, but the only way to get stuff visible on screen with 800 width and the extron is to make the pic extremely fuzzy. So thats not helping either.

I then showed two possible work arounds:
Setting Width to 799, with the result, that phase is not perfect and edges are fuzzy
Setting alias to add additional pixels. That does work for the width (not for the height).

In the clip you can also see that the 800 width are not automatically applied. So to avoid that software bug the 799 width with the slighty fuzzy edges might be the best solution maybe.

Either way...its a mess.

Reply 1296 of 1403, by vvbee

User metadata
Rank Oldbie
Rank
Oldbie

One way to do it might be to write custom functionality for VCS that samples two captured frames per displayed frame (halves the output rate though), changing the horizontal position by one pixel for every second frame and constructing a full frame for display from the two partial ones. But I've no idea what effect constantly changing the video mode parameters would have on capture performance (or hardware longevity or whatever). Would presumably cause some visual glitches along the pixel-thin vertical edge, but maybe not too bad with relatively static content.

Or was it the case that changing the horizontal positioning in VCS just showed the partial image either way? It's been too long since I've tried. Not much help if so, assuming an external device can't be set up to alternate the proper positioning every second frame. Though I remember adjusting the phase setting in VCS from one extreme to the other in some cases shifting the image left or right by a pixel or so, but can't remember if the image quality was otherwise good in those cases.

Reply 1297 of 1403, by Kordanor

User metadata
Rank Member
Rank
Member

You can see that in the video i posted above. I show what impact horizontal positioning has with VCS and what it has with the Extron (its the same). I also show how it looks like without the extron (at 6:28). So without the extron the Horizontal is fine. The Vertical however is missing several pixels without the Extron and is only missing 1 pixel without the extron (and this pixel isn't just gone due to "height", it's actually impossible to get it)

Reply 1298 of 1403, by vvbee

User metadata
Rank Oldbie
Rank
Oldbie

I'm not involved in it so much to be watching videos about it, but basically frame reconstruction is an option if there's a way to alternate the side that's missing. If not, out of luck on that front.

With vertical alignment, I remember the VisionRGB-E not being as good as the VisionRGB-PRO. I've recommended the PRO for DOS capture anyway, but you need a retro capture machine for it.

Reply 1299 of 1403, by THEBaratusII

User metadata
Rank Newbie
Rank
Newbie

Not sure if this is the right topic to bring this up in, but I am having some trouble outputting 720x400 resolution on my Gefen EXT-VGA-2-DVISP.

It keeps outputting it as 640x350 instead of it's intended resolution, I've tried resetting it, switching PCs with different graphics cards and hooked it up with a monitor to no avail. I am wondering if it's anything firmware related?

3hgpJoa.png

Z6rBOy0.gif
My Website
YouTube Channel