tracking motion off screen issues
by Algae998
on
Jun 21, 2007 at 7:20:10 pm
Hey all,
In my footage Im trying to track the position of a garage roof and a tree in the background. After a couple seconds the camera quickly rotates downwards to face the ground. Ive tried placing the motion tracking and rotation tracking, which works well for the short stable section but when the camera rotates the points just jump around and do not follow the points off screen.
Is it possible for the motion tracking to do this or could it possibly not be keeping up with the speed of the rotation?
Im not too sure of the capabilites of motion tracking or if I should use corner tracking.
Re: tracking motion off screen issues by yikesmikes on Jun 21, 2007 at 8:42:03 pm
The points you were tracking probably jumped outside that little squares, so you need to adjust then manually.
For a step by step on adjusting a track that goes bad (Tracks gone bad! the movie) see the 3rd part of Aharon's series on turning video into cartoons, there he tracks an eye onto the character. It's only a 1 point track but the same principal. He shows you how to adjust them manually, frame by frame. Hope it help.
Aharon's tut, what you want is in Part 3, and starts at the 5 minute mark:
Re: tracking motion off screen issues by Algae998 on Jun 22, 2007 at 1:16:47 am
Thanks for the advice. I remember watching those videos and took another looks at them. I tinkered with my video and did something similar. The problem was that the speed at which the camera rotates it blurrs the pixels the tracker points lock onto so it just jumps around. I had to go back and manualy relocate each of the 10 or so tracker points; no big deal. Good thing is is now it works!
Thanks for the tutorial links!
Re: tracking motion off screen issues by Darby Edelen on Jun 22, 2007 at 4:28:57 pm
Motion blur is the number one killer of motion tracks. If you can find a decent way of cutting down on the blur enough to have trackable points (sharpening the footage?) that will help. Just remember, your track doesn't have come directly from the footage you want the viewer to see!
Darby Edelen DVD Menu Artist Left Coast Digital Aptos, CA
