Composite Tracking

codepunk wrote on 6/14/2004, 4:56 PM
Ok, first off, I made the subject term up (if it's a real term, then it's purely by coincidence since I've never heard it). Here's my question with a little background info first.

My short (actually a series of 3 shorts) is the classic good and evil consciences' on a person's shoulder type of story. I shot the good and evil conscience's on a green screen and then chromakeyed them onto the shoulders. The first video was fine since the actor playing the main guy kept his shoulders relatively still (thus minimizing any track motion work I would have to do).

Now, the 2nd video was a little more risky. The good and evil conscience appear on the dash of the person's moving car. First mistake...I didn't use a tripod in the car so the video was very bouncy. Well, I didn't have time to reshoot (since it was for a church video due that week).

So, here's the actual question: Is there some sort of way to basically tell a video track to track something from another track (I'm guessing not). In other words, let's say I used the rear view mirror from the parent track as the "object" to follow. If the rear view mirror moves 5 pixels up, the child tracks also follow suit. I sure hope this makes sense to anyone. Let me know if you need more info.

-Mark

Comments

[r]Evolution wrote on 6/14/2004, 6:28 PM
It may be easier to run it through something like 'Dynapel Steady Hand' first. If you do this to your source phootage it will take out most of the camera shake. It will not make it look like it was shot on a tripod but it will at least make the movement a lot smoother. You may still have to 'track Motion' in a few keyframes but by steadying your source, your phootage and keyframes will be a lot smoother and you will need a lot less keyframes.

skibumm101 wrote on 6/14/2004, 8:11 PM
I think what you are looking foris called motion tracking. I personally use combustion for this. I dont nesacerrily use it for what you are trying to do, but use it for green screen motion tracking. (thats what the little white crosses are on greenscreens you see being used for major movies). Basicly i shoot moving camera shots of actors in front of green screens, then i composite it with either a 3ds max moving background or a live shot background. The white crosses on the green screen are my refrence point. You can do the same thing by picking a refrence poinst in the live action footage.
sacherjj wrote on 6/15/2004, 2:47 PM
When I need to do something quick and dirty for this, I lock the cursor in a pan and crop dialog. Then I figure out a point of reference and use arrow keys to nudge the object to line up. The problem is the arrow key nudging was stolen in Vegas 5. This is really annoying for me. You can't drag accurate enough with the mouse and typing or clicking up or down arrows on position really sucks.