Using gain settings to offset dim picture.

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Viewing 13 posts - 1 through 13 (of 13 total)
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  • February 5, 2019 at 5:05 PM #25087
    drojman
    Participant

      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?

      February 5, 2019 at 5:37 PM #25090
      nmalinoski
      Participant

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

        February 5, 2019 at 6:09 PM #25091
        drojman
        Participant

          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.

          February 5, 2019 at 6:53 PM #25094
          drojman
          Participant

            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?

            February 5, 2019 at 7:04 PM #25095
            Harrumph
            Participant

              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?

              February 5, 2019 at 7:08 PM #25096
              drojman
              Participant

                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.

                February 5, 2019 at 7:16 PM #25098
                Harrumph
                Participant

                  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.

                  February 5, 2019 at 7:33 PM #25099
                  drojman
                  Participant

                    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.

                    February 7, 2019 at 10:03 AM #25124
                    Harrumph
                    Participant

                      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.

                      February 7, 2019 at 1:48 PM #25127
                      drojman
                      Participant

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

                        What’s the difference between gain and offset?

                        February 7, 2019 at 4:26 PM #25129
                        Harrumph
                        Participant

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

                          February 7, 2019 at 4:43 PM #25130
                          SavagePencil
                          Participant

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

                            February 7, 2019 at 6:46 PM #25131
                            drojman
                            Participant

                              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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