Cannot get iMovie to open DV movie

I have many old Quicktime movies that I want to edit. iMovie will not open the QT so I converted toDV but it still will not open it. i was using MPEG Streamclip to convert. I am, however, clueless about movie formats so need to ask for simplest instructions. Other formats offered in Streamclip are: AVI, MPEG 4, and Other. I have iMovie 10.1.1. And MacBook Pro OS 10.11.3. Thank you