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    An input lag investigation

    Scheduled Pinned Locked Moved General Discussion and Gaming
    input lag
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    • S
      ScOULaris @BuZz
      last edited by

      @BuZz said in An input lag investigation:

      The default is not 1080p. The default is the video output resolution, so depends on your screen. afaik it will affect it, as the final scale from render res to video output res is done via dispmanx. I tend to run my tv in 720p for retropie anyway switching it in /boot/config.txt

      Yeah for me the video output resolution is 1080p, so the default render resolution right now is 1080p for all of my emulators as well. Should lowering the render resolution to 720p theoretically lessen input lag because the shader overhead is lessened, or would it actually increase input delay because it would add an extra scaling step to bring the render resolution up to the video output res?

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      • BuZzB
        BuZz administrators
        last edited by

        It should reduce lag in theory, but instead of doing that, if your tv upscales from 720p well, you could just use a 720p video mode. It is possible that screens that have a delay due to post processing could be quicker at a lower res also.

        dispmanx also scales with a filter by default, so it might look better with a 720p video mode with the tv doing the scaling vs dispmanx (I prefer it on my tv)

        To help us help you - please make sure you read the sticky topics before posting - https://retropie.org.uk/forum/topic/3/read-this-first

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        • davejD
          davej @ScOULaris
          last edited by

          @ScOULaris said in An input lag investigation:

          Hm. So I understand how a shader can add more input delay (increasingly in correlation with the complexity of the shader). Would lowering the Retroarch rendering resolution to 720p instead of the default 1080p for SNES have any impact on input delay since it's half of the pixels that need to be processed by the shader?

          Yes, but probably not as much as you'd think. You'll also have poorer image quality to deal with. crt-pi's scan lines work best when scaling up 4x or more. If you are going to use a lower resolution than that I'd suggest using integer scaling - and don't go below 3x.

          Scaling in the display hardware is essentially free but you are probably better off setting your Pi to a 720p screen mode and letting your TV do the upscaling. Try both and see which works best. If the scan lines are hard to see with such as low resolution, try setting MASK_TYPE to 0.

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          • BuZzB
            BuZz administrators
            last edited by BuZz

            Just to detail my tv/kodi setup downstairs:

            /boot/config.txt contains

            hdmi_group=1
            hdmi_mode=4
            

            which is 720 @ 60hz

            /opt/retropie/configs/all/autostart.sh contains

            sudo mount -t cifs -o username=blah,password=blah //mynas/retropie /home/pi/RetroPie
            kodi #auto
            emulationstation #auto
            

            kodi is configured to display and output at 1080p (it can change video mode itself)

            then I exit kodi, and I'm ready to game (in 720p)

            the only other thing I have to do is switch the tv to game mode and back.

            To help us help you - please make sure you read the sticky topics before posting - https://retropie.org.uk/forum/topic/3/read-this-first

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            • scrappbrappS
              scrappbrapp
              last edited by

              how do you change the display driver to Dispmanx? i assume mine is running stock, i never knew how to change.. Ive also yet to learn about shaders, so I'm not too worried about losing that ability.

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              • BuZzB
                BuZz administrators
                last edited by

                you can do it via the configuration editor (in advanced mode)

                https://github.com/retropie/retropie-setup/wiki/Configuration-Editor

                To help us help you - please make sure you read the sticky topics before posting - https://retropie.org.uk/forum/topic/3/read-this-first

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                • scrappbrappS
                  scrappbrapp
                  last edited by

                  thank you, i found it.
                  Unfortunately, i think I noticed WORSE play on dispmanx.... I can tell that the video quality is worse... but mashing jump in mario world created a worse experience than before with GL. Also trying to do a "speed run" caused me to not have some jumps registered, thus plowing right into enemies...

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                  • scrappbrappS
                    scrappbrapp
                    last edited by

                    This post is deleted!
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                    • S
                      silentq
                      last edited by

                      I updated from binary and source and changed over to dismanx, I thought the video smoothing was supposed to be gone? I even tried to turn it off in retroarch.cfg for lr-fceumm by make video_smoothing="false" and its still there? Am I missing something?

                      BuZzB 1 Reply Last reply Reply Quote 0
                      • BuZzB
                        BuZz administrators @silentq
                        last edited by

                        @silentq need to build latest retroarch from source. It only recently got support for switching scaling mode

                        To help us help you - please make sure you read the sticky topics before posting - https://retropie.org.uk/forum/topic/3/read-this-first

                        BuZzB 1 Reply Last reply Reply Quote 0
                        • BuZzB
                          BuZz administrators @BuZz
                          last edited by

                          At least as I remember

                          To help us help you - please make sure you read the sticky topics before posting - https://retropie.org.uk/forum/topic/3/read-this-first

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                          • S
                            silentq
                            last edited by silentq

                            Not sure if this is a bug, its not really major but I noticed using the dismanx driver that the retroarch status notifications at the bottom of the screen don't show anymore. Status messages like when you save or load state or a input remapping status don't show. Just thought I would mention it its not major but figured I would add that.

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                            • RionR
                              Rion
                              last edited by

                              Sorry to reply to and old thread but this is the updated link to the same Thread at the libretro forums. I think this one is more up to date.

                              @Brunnis
                              An input lag investigation

                              FBNeo rom filtering
                              Mame2003 Arcade Bezels
                              Fba Arcade Bezels
                              Fba NeoGeo Bezels

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                              • P
                                pattaboy
                                last edited by

                                I have noticed some input lag on psx games. especially when playing my childhood game bust a groove. Where you need timing to play the game. I couldn't even do one dancemove when pressing the button. Has this ever been noticed that the PSX emulator has input lag?

                                RionR 1 Reply Last reply Reply Quote 0
                                • RionR
                                  Rion @pattaboy
                                  last edited by

                                  @pattaboy Every emulator, if it's on Windows, Linux or Mac has some form of input lag.

                                  Just read this thread and the one on Libretro to try different things that might help.

                                  Just to name a few

                                  • Game Mode on you TV

                                  • Runcommand set to Performance

                                  • Render Resolution

                                  FBNeo rom filtering
                                  Mame2003 Arcade Bezels
                                  Fba Arcade Bezels
                                  Fba NeoGeo Bezels

                                  1 Reply Last reply Reply Quote 1
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