Lagging video from blackmagic unless i disable beam sync

edited August 2014 in MAIN
I'm getting a PAL signal via a blackmagic grabber. When i display that image on the projector (60Hz) the video is lagging in an annoying way, is simply not smooth. The framerate of millumin is around 34fps weirdly enough. If i then disable beam sync on the mac (in quartz debug), then the framerate jumps up to 60fps, and the video stops lagging. Its super smooth. But now i get the vertical sync lines in the image of course. 

Are there any tricks to get better performance without disabling beam sync? 


  • Hello @HalfdanJ,

    "Beam sync" in a settings to enable/disable vertical syncing, so all the display managed by OSX are synchronous. This is very recommanded, as no vertical syncing means "screen tearing" (seeing scanlines). Just as you observed.

    I doubt vertical sync could change the way Blackmagic acquires the signal.
    Millumin uses Blackmagic own libraries, the same as BlackMagic Media Express software : did you run a test with it ?
    Also, did you try to unplug all your displays (except the one for the main screen of course) ?
    Lastly, did you contact Bmackmagic support about this issue ? This may not be related to Millumin.

    Best. Philippe
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