Since I published my short update on the Mars 2020 plans, I've learned that the current plans for the mission do not include a descent imager. As a result, there currently will not be the equivalent to the descent movie made for the Curiosity landing. I apparently misunderstood a point on an earlier presentation I read.
The project engineers are still evaluating a Terrain Relative Navigation system to guide the rover to a safe landing. That system would require a down looking camera. I have not heard whether that camera would make movies or record still images for later analysis or release to the public.