Frames dropping every 4s. when BM HDMI to SDI is used.


Im having an issue I can't get over. Maybe someone had the same problem.

I'm using macPro2019. One output it the GUI, second is 4k 50hz to RGBlink processor, third 1920x1080p 50hz goes to BM HDMI to SDI converter and next to optic fibre converter.

In this setup FPS drops from 50 to 48 every around 4 seconds. It seems that whole system drops in that moment as even the cursor stops while being moved over the desktop.

Unpluging the BM device resolves the issue. Using ImagePro 2 causes the same problem.

Activity monitor doesn't show any peaks or drops in system performance.

Any Idea any one?




  • Hello @Mariusz,

    Another user reported a similar issue : it is not related to Millumin, but rather an issue between the MacPro 2019 and the converter.

    I wrote an email to Blackmagic's engineers to know if it is a known issue.

    From testing, a HDMI splitter "that can kill HDCP" seems to be a workaround (no problem if this splitter is connected to the computer then to the converter). Do you have a HDMI splitter ? If so, does it change anything ?

    Best. Philippe

  • Hi Philippe,

    Thank you for such a quick response.

    The same issue has occurred when I've connected ImageProII via HDMI and DP. So I don't think its a problem specific to BM.

    I don't have a HDMI splitter at the moment but I used EXTRONs EDID101D which isn't HDCP compliant and the problem persists so again doesn't look like HDCP authorisation issue..

    Ill try to get some Chinese splitters, converters and let you know if it helps.

    If you'll have any new info on this issue please let me know.



  • Hi @Mariusz,

    I'm the other user having this exact same issue with our 2019 Mac Pro. I'm also hesitant to think that it's a BMD issue, as I've been having the frame drop issue prior to having any BMD hardware involved.

    It sounds like we're having the same exact issue (although we're running Millumin at 60hz instead of 50hz). Mouse briefly freezes, and framerate drop down from 60 to 56-58 every 3-4 seconds. Issue occurs with or without Millumin running.

    The issue only occurs when I connect any type of HDMI to SDI conversion to an output of our GPU. The issue also occurs if I connect HDMI or DP directly from MacPro GPU to our E2.

    I have yet to try an HDMI splitter to see if it's an HDCP issue. Will post back here if I do give it a try. Please post if you find out anything more on your side! I've spent so many hours trying to troubleshoot this - especially after investing so much money in the new Mac Pro.



  • Hi Ethan, Philipe!

    Any new info on the discussed issue?

    Ethan what GPU are you using?

  • Hello @Mariusz & @ethan_tripp,

    I just spoke to Blackmagic support, and an update for converters has been released last week : Blackmagic Converters 7.5.3 Update.

    Could you please update the firmware of your devices, then check if the problem persists ? Thank you.

    Best. Philippe

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