I rotobrushed person's head in a video footage. I scrubbed through the Timeline to make sure that only the head is visible. Being satisfied with the result, I then duplicated the rotobrushed head layer, applied Time Reverse Layer and then moved the layer with Time Reverse to the end of the original layer. Now, when the Timeline Indicator the last frame of the original layer and enters the first frame of the duplicate layer with Time Reverse, all the contents of the original footage are being shown (i.e. not only the head, but the background, other persons' faces, etc.). And when the Timeline Indicator enters the second frame (and all the rest of the frames) of the layer with Time Reverse, the rotobrushed head is displayed properly again.
To solve that single "bad frame" problem, i deleted the layer with Time Reverse, trimmed the original rotoscoped footage by 1 frame, then duplicated it again, applied Time Reverse on the copy and placed it at the end of the original layer (just as before). Now I did not get that single "unrotoscoped" frame when the Timeline Indicator entered the layer with Time Reverse and as i thought that the problem is solved, I precomposed these 2 layers..
I scrubbed through the precomp and everything looked fine. Then I did some editing on another comp and after about 30 minutes i added the precomp to that anther composition. And when i was scrubbing through that composition, the rotoscoped head footage began to display SOME of the unwanted contents at CERTAIN frames. In other words, the precomposition is ruined. And the strangest part is that when i go the the precomposition itself and scrub throughout the Timeline, I do not see any unwanted background contents at all - the head looks perfectly rotoscoped. So, I simply cannot correct the rotoscoped areas because i don't see any unwanted contents in the precomp. Only when that precomp is added to another comp as a layer, then some unwanted contants are displayed at some moments.
Is it a bad practice to duplicate layer and apply Time Reverse on one of them or what?
I want to loop a short movement of a rotoscoped head, that's all
Do you need any printscreens?
Pre-render your rotoscoped work to an intermediate clip or image sequence with Alpha.