archival 18p playback question

normally i work at 24fps but recently have been given some 18p archival footage. my normal workflow is to edit in resolve, viewing my timeline output on a large screen monitor driven via hdmi through a decklink studio 4k card. i'm getting smooth playback within resolve of the new 18p materials but the large-screen is stuttering. i'm guessing that the decklink card is the problem in this scenario. is there a solution that doesn't involve getting a different card or box? what settings would one use in this case?

thanks,
g

Card will be sending most likely 24p (some frames are repeated) as there is no standard for 18fps over HDMI or SDI (if I'm correct). Not much you can do about it.

thanks for the info, andrew. i've got it working as well (better, actually) as can be expected. i'd been having an issue with prores playback on linux and when that issue got solved, the 18p-big-monitor-playback issue disappeared as well. it does look like there are extra frames being thrown in to get to 24p but the playback is actually smoother than it had been and smoother than i expected. thanks for the tips,

G