Motion Tracking concept not grasped
by tim vanbrackle on Nov 6, 2011 at 6:05:17 am
I am perplexed and need help. I am trying to stabilize some tracked footage:
I am using the motion tracker in after effects in cs5. I set up a green screen (ps. I know it's a bad key, and thats not the background i am going to use, right now just want the footage smoothed out for a tracking shot to put in a background later)
I used a glide. I wanted the motion tracker to stabilize the x axis, but I still get the "floating bar look". (plus it slides off the side of the screen.) am i totally using the wrong tool for this? Any help would be greatly appreciated thanks.
Posting the original chroma footage will help (without any post on it).
Since the perspective changes in your shot, I would choose a 3d tracker like Camera Tracker from the Foundry. This will give you a camera in AE that matches the real camera. That will enable you to composite a background that will match not only the move but the perspective change as well. Then you can deal with stabilizing the move on the Y axis (not the x axis- that's why the image moves to the side).
Do take note that you will have to rotoscope out the markers, which isn't covered out in the linked tutorial. The rotoscope requirement isn't too difficult if you cut some slack on the edges of the hair but it's still a lot of unnecessary work!
Now, back to your main issues, which involve production techniques and values. Do set aside a budget for an, on-set VizFX Supervisor the next time you venture out on a VizFX job. This shoot was done without an idea of how to piece things together in post and that's a disaster already in the happening. 'Fix it in post' is bad enough a thought, even when a solution to how to fix it in post is known.
The COW's job forum and your own contacts will allow you to link up with folks that will not only do the job but allow you to assimilate some useful knowledge/tips while on the job.
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