[Cin] Tracking (or tracer?) control points

[Andrea paz]

I don't think Tracer plugin is suitable: too variable, especially when
associated with keyframes.
The only way is the second video: Roto + Motion tracking.
In theory it is possible to associate a green screen with Cinelerra's
Motion Tracking. But this plugin is slow, heavy and complicated. I
hardly reach good results, even more so if there are curvilinear as
well as linear movements. Maybe it's better to work manually with mask
+ keyframes (without using green screen); but the result will never be
as good as Roto + Motion Tracking, because of the Edge Jitter and the
gap between background and object.
(in your video you can make a "de spill" to mitigate the green halo.)
Roto + Motion Tracking would be a wonderful addition; DaVinci Resolve,
Premiere Pro and Edius have these tools even without going through
After Effects or Fusion.