MP forces VSYNC on. (1 Viewer)

SciDoctor

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  • February 2, 2005
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    This doesn't show in the logs .

    Overides display driver settings.

    Will not show aberations when your GPU can do tripple buffering in direct x but will if you only have double buffering available .

    Symptons are you can't have scroll speed set greater than monitor refresh (set in drivers), not to much of a problem BUT...

    Playing any video that has FPS less than screen refresh and greater than half screen refresh will force video output and MP GUI to half of screen refresh. (VSYNC on /double buffer)

    ie 60FPS screen refresh will have no problems with 24,25,29,30 FPS video material BUT 50 FPS material will be forced to 30FPS giving stutter and frame drops.

    If you have a display capable of 50FPS screen refresh (set at 50FPS) then 30FPS material will be forced to 25FPS giving stutter and frame drops.

    The same 50FPS capable monitor is now set at 75FPS because of the above , now 30FPS will be fine but 50FPS video will be vorced to 37.5 FPS.

    With MP playing videos with such a wide choice of FPS having VSYNC forced on is undesireable espeacilay when you can't guarantee that the GPU has tripple buffering with VSYNC or even good/stable VSYNC options.

    MP also doesn't have dynamic control over monitor set screen refresh which would give ultimate matching of desired FPS per VIDEO FPS. Although tripple buffering does in the way it works eliminate the halving FPS that VSYNC incurs.

    At least an option for the user to select if VSYNC is desired would be good.
     

    Spragleknas

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  • December 21, 2005
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    Hm... I read somewhere that MP did not force vsync - but that it should ...
    I've forced vsync myself so I never bothered checking. I did this after reading a lot - not by testing.
     

    SciDoctor

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    Thanks .

    Ensure VSYNC is turned off in display drivers.

    If you can now have scroll speed set greater than refresh rate VSYNC is definately OFF, if you can't then MP is forcing VSYNC on.

    Now depending on your GPU and drivers is how well desired FPS of video material is respected with VSYNC ON and is down to double (bad) or tripple (good) buffering.
     

    ronilse

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  • July 19, 2005
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    Hi,
    Not able to confirm this with vista x64 & nvidia card(latest drivers & it output to svhs), i had to enable it manually to get rid of some line glitches...

    Regards
    Roy
     

    SciDoctor

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  • February 2, 2005
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    What FPS are you achieving ?

    In GUI only and then with video fullscreen and video + gui.?

    It only occurs when FPS drops bellow screen refresh and is worse when the GPU has no or bad tripple buffering.
     

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