October 1, 2017 at 6:03 PM #15577
I’m getting a strong dithering and checkerbox pattern across my screen when I use my Dreamcast witg my VGA box through the OSSC. When I plug the VGA box straight into the TV, however, I get a completely clean image. I have tried and tested with the same results on two televisions and two different VGA cables. Has anyone else come across this issue? Could It be that The OSSC doesn’t like the signal from my VGA box.
October 1, 2017 at 9:07 PM #15582
- This topic was modified 1 month, 3 weeks ago by Wilco.
Never noticed anything like that here, and Dreamcast VGA boxes should all be the same. Are you using the recommended settings for Dreamcast VGA as per the wiki?October 2, 2017 at 5:08 PM #15607
Yeah, I’m using DTV in 480, but it still looks bad.
This is a picture of the image straight through into my TV.
And this one is when it passes through the OSSC.
The image is not only darker in the second picture but the dithering and checkerbox effect is dramatically increased. It’s also apparent when capturing the image via an Elgato HD60.
October 2, 2017 at 5:16 PM #15609
- This reply was modified 1 month, 3 weeks ago by Wilco.
Hmm, that is strange I wonder if this is what happened to Adam Koralik’s Dreamcast (only other person to complain about poor video quality with OSSC and Dreamcast so far).
Did you try the other fixes i.e changing H.active to 640 in the advanced timing menu and ajusting H.backporch to centre image?
October 2, 2017 at 5:38 PM #15611
- This reply was modified 1 month, 3 weeks ago by BuckoA51.
Yeah I have also tried that but still, nothing makes it better. I saw Adam’s review and wondered whether this may be the same problem. What do you suggest I do? As the Dreamcast was a big reason for me getting this.
Cheers.October 2, 2017 at 5:55 PM #15614
You say you have tried two different VGA cables, was that the full cable and box or just a cable.
Admittedly I’m clutching at straws here, really puzzled.October 2, 2017 at 6:18 PM #15615
Yeah me too. It was two separate VGA cables both tested with the same VGA box. It’s super weird as everybody else has raved about the Dreamcast image being incredible. I hope I’m not missing something super obvious. Would it be worth sending the unit back for testing?October 2, 2017 at 9:37 PM #15617
This appears to be a case of dithering being revealed by the clearer picture of the OSSC. The Dreamcast connected directly to your TV looks much blurrier than the OSSC.
If you search on Google for ‘Dreamcast dithering’ you will find lots of results with people noticing the dithering even on RGB scart.October 3, 2017 at 11:09 AM #15638
I can spot the dithering on some screens on my Dreamcast now I’m looking for it. It definitely only affects certain screens though, for instance there’s no dithering on the polygons on Crazy TaxiOctober 4, 2017 at 2:09 AM #15660
Agreed with paulb_nl, if you look closely it seems the dithering is present when hooked directly to the TV, to OSSC just reveals this.
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