Horrible Dreamcast Quality with OSSC

[mills]

Hey all,

I recently received my OSSC and plugged my Dreamcast into it via VGA. I did not change any settings, as I don’t have the remote. On my TV, it looks horrible, there’s artifacting and vertical lines everywhere: https://imgur.com/a/nt66M

When I skip the OSSC and just plug VGA directly into a PC monitor, it looks fine: https://i.imgur.com/XfaDHZt.jpg https://i.imgur.com/q36n3Ll.jpg

What gives? I doubt this is normal, and I’m not sure what’s causing it.

[Fnnrqwin]

Have you checked your TV’s settings? Your post makes it sound like the OSSC is plugged into a different screen than if you just plug the Dreamcast in with VGA. Am I correct?

The default settings might not be ideal on the OSSC, but this looks like your TV is doing all sorts of processing, whereas your computer monitor is doing very little to the image.

[mills]

Have you checked your TV’s settings? Your post makes it sound like the OSSC is plugged into a different screen than if you just plug the Dreamcast in with VGA. Am I correct?

To clarify, I’m trying to make it work on my TV (TCL 40FS3800), which only accepts HDMI, so I can only do Dreamcast -> VGA Box -> OSSC -> TV (HDMI). I tried testing Dreamcast -> VGA Box -> PC Monitor (VGA) and the image was fine.

The OSSC’s black-and-white test screen, on my TV via HDMI, does not have any artifacting or vertical lines. It looks perfectly fine.

I adjusted my TV’s settings, and by turning “Sharpness” all the way to 0, the image did get a bit better, but the vertical lines and visual artifacting are still there, just more subtle: https://i.lensdump.com/i/8svb03.jpg https://i.lensdump.com/i/8svwB0.jpg

EDIT: So apparently according to this thread, this is normal, and what I’m seeing is just the dithering effect brought out by the high quality HDMI conversion of the OSSC, that you wouldn’t normally see? https://i.lensdump.com/i/8sLMUe.jpg is this normal?

[FBX]

I do know that there is dithering on Code Veronica for example, and it’s definitely the game itself doing it. Here’s a screenshot I took of a perfectly dialed-in optimal timing image of the title screen:

Code Veronica Title Screen

[Fnnrqwin]

Do you have another 480p console you can test with the OSSC? Your screenshot looks fine to me. Just from the small amount of evidence present, it could just be the lack of image processing (now that you lowered sharpness) is different than what your PC monitor does to the VGA signal.

You should really get a remote for the OSSC. Adjusting the settings makes a huge difference. I don’t think I have a single console that looked ideal just using defaults.

[BuckoA51]

For the Dreamcast you definitely want to dial in the correct (baseline) settings as per the wiki page here:- http://junkerhq.net/xrgb/index.php?title=Dreamcast

[Teddy Rogers]

It looks like that because you haven’t (correctly) configured the OSSC. You need to enforce the sampler to 480p and adjust active/backporch settings for H & V to suite your display…

Ted.

[mills]

Do you have another 480p console you can test with the OSSC?

Unfortunately, no, not yet.

For the Dreamcast you definitely want to dial in the correct (baseline) settings as per the wiki page here:- http://junkerhq.net/xrgb/index.php?title=Dreamcast

It looks like that because you haven’t (correctly) configured the OSSC. You need to enforce the sampler to 480p and adjust active/backporch settings for H & V to suite your display…

I have configured a remote and adjusted the settings. H.active is set to 640, as by default. “480p in sampler” cannot be set to “DTV 480p”, as it causes a black screen, so I have to use the other mode (VESA).

Not sure what other settings I could adjust.

[Anonymous]

That could be a big part of your issue there.
It seems your TV doesnt support 640×480 and wont natively display 720×480 but rather is internally scaling 720×480….which it doesn’t sound like it’s doing very well. Have your tried line2x? You might get lucky and hit a native resolution in your TV at 1280×960 or 1440×960.

The user guide and spec sheet for your TV aren’t very helpful. Just say max res of 1920×1080 and ntsc. But it is 120 hz. Anybody have any opinions in whether 120hz would create any potential for not playing nice with the ossc? I would assume no, but thought it worth asking.

[BuckoA51]

“480p in sampler” cannot be set to “DTV 480p”, as it causes a black screen, so I have to use the other mode (VESA).

That’s extremely odd. If anything, DTV 480p is the standard not VESA 640×480.

[Author]

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