OSSC “Combing” Effect on HP 25x Monitor

[DustinVG]

Hi there, since it seemed like it might be a while yet until the OSSC Pro comes out, I decided to order the original and give that a go. So far, I’m pretty satisfied, but there’s one problem I was wondering if y’all could give me some insight on.

See, I like to do livestreams, so I tend to have it set up to where my consoles go into my capture card (an Elgato 4K60 Pro Mk. 2) and are then output into my monitor (a HP 25x 1080p 144hz monitor, serial number 3wl50aa). However, while the OSSC is fairly compatible with this monitor, it sometimes produces a strange “combing” effect on the edges of pixels, which is varying levels of distracting. However, it seems to look fine on my other monitor and in my capture software. I could use the former, but it only has 1 HDMI in and I don’t currently have any hardware to make the act of switching the two easier.

I’m using FirebrandX’s OSSC optimal timing profiles and slightly adjusting the sample rate seems to mitigate these issues, but of course, also brings with it some other graphical artifacts. It seems it may have to do specifically with 244p, as it occurs more frequently there and less with actual 240p, but I don’t have enough data to say that with confidence.

Thank you for any input you may have.

[Zacabeb]

When I’ve encountered this on an old Sony TV, it’s been because the sample rate has been an odd number per line. I don’t know if the cause is the same here.

[DustinVG]

Yeah, I had noticed this before, but declined to utilize it since I believed it created a sort of “shadow halo” effect in its stead. However, upon closer inspection, that seems to be present regardless, so I’ll admit I feel a bit silly now.

Though, the upper left corner does seem a bit funky.

[Harrumph]

My general advice would be to use generic mode instead. If you can’t use the exact samplerate of the console, then it’s not “optimized mode” in the true sense anyway, and you just introduce new artefacts.

Another suggestion, looking at your last SNES image, you have quite bad crosshatching, which can be either a bad RGB cable (expecially if it’s wired sync on composite video), or you have a model of SNES motherboard (APU-01) that requires a mod to fix the crosshatching. See here: SNES diagonal lines fix

Finally, can the Elgato really passthrough to your monitor without lag? I would suggest using a splitter and send the signals to monitor and capture card separately.

[DustinVG]

My general advice would be to use generic mode instead. If you can’t use the exact samplerate of the console, then it’s not “optimized mode” in the true sense anyway, and you just introduce new artefacts.

Well, maybe, but getting a more 1:1 scale than was really possible with the XRGB Mini was a big appeal with this product to me, so it’d be a little disappointing to let it go so easily, especially when it works with the rest of my stuff fine.

Another suggestion, looking at your last SNES image, you have quite bad crosshatching, which can be either a bad RGB cable (expecially if it’s wired sync on composite video), or you have a model of SNES motherboard (APU-01) that requires a mod to fix the crosshatching. See here: SNES diagonal lines fix

Hmm… I’m using a csync cable from Retro Access, yes. The mod is tempting, but I’m not entirely sure offhand which motherboard version I have, and I don’t quite have the equipment to do this cleanly or safely.

Finally, can the Elgato really passthrough to your monitor without lag? I would suggest using a splitter and send the signals to monitor and capture card separately.

Admittedly, I’m not quite sure if it’s as “lagless” as it claims to be, though the only HDMI splitters I have on me are either really finicky, or only have 2 outputs (I use one output for my audio extractor).

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