VOGONS


Voodoo2: video is offset

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First post, by mrfusion92

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Hi, do I have a faulty Diamond Monster 3D II? As you can see in the screenshots the screen screen is offset to the right.

Right now I'm capturing the PC throught a VGA-HDMI converter, but the issue appears also with a VGA monitor connected directly. It is a LCD tho, I don't have a CRT.
It happens only with games that use the Voodoo, and I had to set the refresh rate to 75Hz otherwise the screen was offset to the top too.

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Reply 2 of 27, by konc

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Are you sure that it's not just the monitor? I mean position adjustment for that resolution/refresh rate it switches to when a glide game starts. Sorry if I'm saying the obvious.

Reply 3 of 27, by mrfusion92

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kitten.may.cry wrote on 2022-06-14, 11:46:

Did you try to move the preview around in OBS?

Seems trivial as balls.

Click on it, and drag to the left, until it snaps.

It happens also with a vga monitor, I wrote it in the OP 😉

konc wrote on 2022-06-14, 11:48:

Are you sure that it's not just the monitor? I mean position adjustment for that resolution/refresh rate it switches to when a glide game starts. Sorry if I'm saying the obvious.

Yes, I don't have the options for position adjustments in the video capture device but I tried to change them while using the VGA monitor. It's like the image that is rendered that way.

Here screenshot that shows normal desktop and the black bar is not present.

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Later I can also make a photo while outputting to the real VGA monitor, but like I said the issue is exactly the same.

Reply 4 of 27, by The Serpent Rider

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Desktop and Voodoo 2 are two completely separate video sources. Also LCD is not a real VGA monitor and even CRT requires some manual adjustments for analog signal.

It's like the image that is rendered that way.

Well, obviously. You're looking at digital conversion, which already includes black bar as a part of video source.

Last edited by The Serpent Rider on 2022-06-14, 12:16. Edited 1 time in total.

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Reply 5 of 27, by mrfusion92

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The Serpent Rider wrote on 2022-06-14, 12:10:

Desktop and Voodoo 2 are two completely separate video sources. Also LCD is not real VGA monitor and even CRT requires some manual adjustments for analog signal.

I know it was just strange that the exact issue was present in all the monitors I tried and with the video capture device too. Different resolutions, refresh rates, horizontal/vertical position adjustments. That black bar is always present.

Reply 6 of 27, by The Serpent Rider

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For troubleshooting, you need output which can adjust analog signal. It's simple as that.

I must be some kind of standard: the anonymous gangbanger of the 21st century.

Reply 8 of 27, by Tiido

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Aren't there image centering controls in Voodoo control panel or that applies only to Banshee and later cards ?

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Reply 9 of 27, by Kahenraz

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I don't understand why the image would be offset on both the 2D and the 3D card across different displays. That doesn't make any sense. Maybe one or the other, or both on one monitor that has some kind of problem.

Am I misunderstanding?

Reply 10 of 27, by The Serpent Rider

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Tiido wrote:

Aren't there image centering controls in Voodoo control panel or that applies only to Banshee and later cards ?

Only for Voodoo 2 with TV-Out, like Quantum 3D Obsidian and Canopus.

I must be some kind of standard: the anonymous gangbanger of the 21st century.

Reply 11 of 27, by mrfusion92

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Ordered on amazon an OSSC clone, it should arrive today.
Never used something like that, I don't even know if it may help. I know that it has tons of settings, and it's not so easy to configure. I will try, I can always return it after.

Reply 12 of 27, by kitten.may.cry

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Kahenraz wrote on 2022-06-15, 03:38:

I don't understand why the image would be offset on both the 2D and the 3D card across different displays. That doesn't make any sense. Maybe one or the other, or both on one monitor that has some kind of problem.

Am I misunderstanding?

It's clearly some basic thing going on, but OP made it look overly complicated, and people went for the "O.C" aspect of it instead.

Reply 13 of 27, by mrfusion92

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Basic thing or not, it's only the Voodoo output that it's giving this issue. The FX 5200 on the same PC displays fine, same the ET4000 on an IBM PC... heck even the Commodore 64 too! Picture always centered and not cropped. Everything tested with real monitors and video captured through adapters. I asked here because I already did all the basic things I could try (like I said I do not have a CRT monitor).

EDIT: I tested also various older Nvidia and Matrox graphic cards.

Reply 14 of 27, by Kahenraz

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I wonder if there is something that is affecting the timing of the clock crystal ever so slightly. Find a bright lamp or a flashlight and check the board for bent pins or a missing surface component. This is extremely common with boards off this vintage.

The crystal might be bad too. I'm pretty confident that this is a timing issue. I'm shocked that an LCD can't lock into the signal. What's going on with the front/back porch?

Are there any tools or display tabs for the Voodoo 2 where he can tweak the display timings to compensate?

Reply 15 of 27, by konc

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You said that you tried with a real monitor and you have the same issue.
My question is, why don't you adjust the image position from the real monitor when the image is not in the correct place? It will remember the setting next time for that particular output of the voodoo.
I'm sure I'm missing something here, just trying to understand.

Reply 16 of 27, by mrfusion92

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Done it, I wrote that in the earlier posts. I tried with those settings in the monitors, but the whole picture moves with the black bar too. Like @The Serpent Rider said is surely because the image is already digitalized that way.

Reply 17 of 27, by rasz_pl

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mrfusion92 wrote on 2022-06-15, 13:00:

Done it, I wrote that in the earlier posts. I tried with those settings in the monitors, but the whole picture moves with the black bar too.

The whole point of LCD position tuning is to move 'whole picture'

mrfusion92 wrote on 2022-06-15, 13:00:

Like @The Serpent Rider said is surely because the image is already digitalized that way.

thats what OSD corrections do on analog inputs in LCD monitors, they correct clock count/skew/phase
Analog capture card should also have those options, dumb vga-hdmi converters dont. Change refresh rate on the voodoo and picture position will also change. Can't set 60 Hz refresh rate at 512 x 384 Voodoo 2 SLI

Reply 18 of 27, by maxtherabbit

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This is 100% normal. The V2 has different backporch timings. It is what it is.

EDIT: I see you bought an OSSC. In order to get truly good results with the OSSC you will need to feed the syncs to AV3 and the colours to AV1 or 2. This is due to the piss poor low pass filtering on AV3. V2 very much needs LPF to look good digitised.

Additionally, you will need to make separate profiles on the OSSC for the voodoo and the primary 2d card. Otherwise you will still have the same offset issue.