Production Switchers

I am trying to input a iMac running Sierra into our Carbonite Black Solos HDMI One input. I see the desktop but as best I can describe the image is scanning vertically. Is this because my computer is outputting 1080i at 60 instead of 59.94? If that is the case what is the best way to force my mac to 59.94?

Actually the same thing is happening with a gopro Hero4 that I inputted into MDMI 2. Same issue?

Thanks in advance!

You have to turn on frame syncs to lock the video. Those are in the reference menu.
#Carbonite

Thanks so much, I'm still on a learning curve with live video production.
#Carbonite