Hi there —–
— as Walter points out there are some combinations of scale and speed that just do not go with the frame rate and will always jitter however there is almost always something that can be done that makes the job ok …… though sometimes it takes a lot of tweaking to get it quite right ….
I am clutching at straws a bit as I havent seen the footage but if you havent already tried these its worth considering the following I think …..
1 ) — if in fields make sure the field order is the correct way round
2 ) — if that does not work try merging the fields so it is frame based
3 ) — this one is pure superstition but I had weird things with tiffs once that were solved by taking the frame into Photoshop and converting it to a targa ( at least I think it what solved it ! )
4 ) — try shifting either the camera of the frame 1 notch in z space …
…. again a bit superstitious by if I have a field problem I always like to make sure I’m on even numbers … so shifting it one notch puts it on an even number if it isnt already … you wont see the size difference…..
5 ) — same on the y axis
6 ) — and obvious stuff / check how you are viewing the end result – is it at 100% ?
………. these checks should clear up the issue if it a ‘glitch’ but if the problem persists I expect it is a technical issue as described by Walter in which case my preference would probably be to keep the still in interlaced fields and add motion blurr .
ALSO ( this can be a useful trick ) I have, in the past, modified selected parts of a difficult frame using a mask or in photoshop.
This technique will probably help in your high contrast areas which are proving difficult ( if the fixes as above do not work )…
In photoshop you can selectively and artisticly ( ? )blurr out offending areas with great accuracy – and to varying degrees as well which can be useful.
If done carefully this should not be too noticeable so that by the time you get it back into AE and add a wee bit of motion blurr it becomes ‘passable’.
I did this once and burred the heck out of just a few edges that were really jittering but it looked ok in the comp because everything else appeared sharp.
Also best remember that you know this problem exists therefore you tend to notice it …. if a few selected ( tiny ) areas are soft no one else is likely to notice it – and probably not even yourself if you were new to the job.
If going down this route using selected blurring really precisely is what pays off … pick on the offending black line ( say )where it looks worst and blurr it to the point that when the motion blur is added as well it looks ok.
Anyway thats my tuppence worth … I wish you well on this one .. I know it can be most infuriating…..
————– chris brett // uk