Hi all.

I shoot with the Osmo in these settings: 3840x2160 30fps
My projects are edited in Avid MC, but my other cameras shoot at 1080i 29.9 fps

When I load the footage into Avid, it looks fine, but during the exporting process, it ends up looking awful.  Full of artifacting and staircasing.  Is there something I'm missing?  Do you know what is the best way to downgrade the footage?
Any help would be great.

Have you tried different editing programs? Like Lightroom, Photoshop, DaVinci ?