Crop out movement?

[SignedupGuest]

Lets say you have a baseball being bounced and the camera moving from right to left (so the ball is moving from left to right on screen). Is there any program that allows me crop out just the baseball? So in other words I can go frame by frame to re-adjust the top/left location for the crop?

[poisondeathray]

Lets say you have a baseball being bounced and the camera moving from right to left (so the ball is moving from left to right on screen). Is there any program that allows me crop out just the baseball? So in other words I can go frame by frame to re-adjust the top/left location for the crop?

I'm a bit confused; can you clarify:

Is the ball being bounced on the ground (vertically) ? or off a wall (horizontally) ?

Did you want to retain the ball in view, but centered ? or Did you mean you want crop out the baseball (ie. remove it)

[SignedupGuest]

I want to keep the ball in frame and 100% in the center. The ball is effectively moving both vertically (the bouncing) and horizontally (the camera pan).

[poisondeathray]

Yes, you can do it manually in an editor for example e.g. sony vegas pro, premiere pro

There are some free programs like center tracker (based on avisynth) you might try .

Or there are programs that can motion track objects and center the shot based on a target eg.after effects, mocha

Those "automatic" non manual ones will often get "confused" by the motion of the camera. You usually have to use a point tracker (like the one in after effects) to get it perfectly centered


Note - when you center the baseball (or any "target") in a shot like this, there will be black edges where there was no data captured (empty parts of the frame).

[SignedupGuest]

I used Vegas and premiere for small misc random task over the years... Assuming vegas is easier to use, whats the technique to do this?

[poisondeathray]

I used Vegas and premiere for small misc random task over the years... Assuming vegas is easier to use, whats the technique to do this?

In vegas (or any editor), you would manually keyframe the position of each frame. Think of it as moving each frame so the ball is at the center of the frame

[budwzr]

Yes, what you do is "stabilize" the ball manually. As mentioned by PDR. In Vegas you would use the Pan/Crop window. You'll probably want to zoom in a bit to give yourself room, depending on the motion, so the frames stay within the border.

[SignedupGuest]

Im familiar with vdubmod, so opening up vegas and premiere is overwhelming. I'm going to read a book on vegas (long over due), ill see how it goes.

[budwzr]

You won't find that in any book. It's an "inferred" technique. The concept is to "counter" the motion with an equal and opposite motion, thereby "neutralizing" it.

The keyframes only need to be placed where the motion "diverges" from a linear path. Like direction changes. If your ball is moving in a straight, or slight curve, you might do the stabilize with only two keyframes. Wouldn't that be nice?

Vegas has envelopes for interpolating the motion between the keyframes, like linear, fast, smooth, hold, etc. that can be useful as well.