Using gain settings to offset dim picture.

[drojman]

Hi folks,

I am using my OSSC to connect to a VGA monitor. However I find my monitor is a little dim. From what I can see I can counteract this slightly by increasing the RGB gain settings on the OSSC itself. Is there any reason not to do this? Am I losing anything by doing so?

Thanks very much.

EDIT, or should I be using the offset options?

[nmalinoski]

Is it just the OSSC output that appears dim, or all sources?

[drojman]

To my untrained eye I would say just the OSSC. The OSSC looks fine on my TV, and my main PC connected via adapter looks okay, if a little saturated.

On reviewing it, if anything it looks to me like the monitor is set to RGB limited, and so crushing blacks. When I set my PC to limited range, it looks perfect on the monitor. Full it crushes severely.

[drojman]

Right, sorry for the double post, but I’m now certain it’s to do with black levels. If I set my PC to the limited range, the monitor looks fantastic.

So the question is, is there somehow I can output limited range from the OSSC?

[Harrumph]

No not currently. There has been request for limited range output, so possibly it will be an option in future firmware. At least Marqs has confirmed there is a test version that has YCbCr 4:4:4 output, which your monitor may interpret correctly. https://www.videogameperfection.com/forums/topic/add-rgb-range-limited-full-output-option/

However, if it is a PC monitor, I find it very strange it doesn’t default to full range, as that is the PC standard. Surely there must be option to set this on the monitor?

[drojman]

Okay, well that’s something. I can test out that hardware at least.

Can someone explain what exactly is being said here:

toggle between limited and full

As I understand it, it is basically possible to adjust it manually to be limited RGB, but I don’t really understand what they’re changing, plus I’m using RGB not component.

[Harrumph]

Right, that would be another way to achieve it. I don’t see what is not clear with paulb_nls explanation.
You can use the grey test screen or 240p test suite to confirm that the changes adjusts the range properly.

[drojman]

It’s just it’s saying lower the gain to full white, and I’m not really sure what value I’m having to change there.

[Harrumph]

For RGB you adjust all three levels with the same value.
Increase the offset first so that blacks are not crushed, then see if gain has to be adjusted for the white level.

[drojman]

I wonder if it’s the adapter I’m using crushing the blacks.

What’s the difference between gain and offset?

[Harrumph]

junkerhq.net/xrgb/index.php?title=OSSC#Video_in_proc

[SavagePencil]

Gain is going to SCALE the output, while offset is going to SHIFT the output.

[drojman]

Sorry I’m totally clueless for this. Would scaling the full range down to limited be the way to go? I would then want to adjust gain. Sorry I’m totally hopeless haha.

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