Weird (interlacing?) artifacts in my rendered video
It is very likely that you have exported your render not as progressive but as interlaced. This would explain the strange artifacts you're experiencing. You can try to deinterlace your footage (a quick google search should prompt you with viable methods) or you might need to export your shot again, but as progressive. Interlaced footage was used to minimize the data required for a fluid motion picture broadcast for TV, there is little to no use in our field of use.