I had a small black dust grain in the lens which is on the same place all the time. Is it possible to define a background (the source of the replacement areas) area without tracking? I mean it would have been much easier to define a static bg area which is all the time behind the object/dot I would like to remove.
At present you must track the background always. We are actually looking to change this for static backgrounds, but often we need to determine the overall lighting anyway to make sure there is no shift in luminosity.
If the background is truly static you can track one frame and then copy/paste the background layer tracking keys in the dopesheet across the whole timeline to save time, but a simple positional track will also work (i.e. don’t track perspective, or shear).
Martin, thank you for the comment. What I have tested so far is this solution for a sequence with fast moving background and result was somewhat satisfying:
I had to set the “Link to track” option in the “Layer Properties” of the both layers to “None”. Then the background layer and the object (that is going to be removed) are not tracked (it is my interpretation of the speed difference), but they both are fixed in one place. With this setup the both processes (the background layer tracking and the object removing) are much faster and there is substantially less work with the background layer adjustment. This is working just for the case when there is a static artefact on the lens/filter/sensor.