AE CS5 - Basic mask keyframing help

[Andrew Paul]

I'm currently editing a music video and am trying to mask out a background window. I've worked with AE before but am no an expert by any means.

 

Basically, the camera doesn't move at all during the shot and the only area I am concerned about is where the artists shoulder crosess over the area in point. I've tried tracking but had little success. I was hoping you guys could give me some tips and pointers to make it as smooth and seemless as possible. Here's what I've been doing so far with sub-par results. Mask out the window and put points where his shoulder meets the window frame and where his arm meets the couch. I have about 3-5 points in between.

 

At first, I was almost trying to do each frame but that was obviously taking too long, so I started doing every 5th frame.

 

 

Small example of my results:

http://vimeo.com/36731811

 

 

I'm wondering:

 

Should I be using "Rove Across Time" ?

Should I have more points?

Feather the mask? How much?

Am I doing this completely wrong? lol

 

Any tips and advice is greatly appreciated.

 

-AP

[Gregory Gesch]

Hi Andrew. I'm a little confused by your image - shouldn't the masks have cut out the windows? Anyway, what I would suggest is mask the window as you have done but ignore his shoulder and estimate where the hidden corner of the window is. Set this mask to 'Subtract' (you should now have a rectangular hole). Now draw another mask where is shoulder is crossing into the hole (leave this set to 'Add', and make it a closed mask), you will see his shoulder appear, move your vertex points to get a clean edge. The important points are the ones that cross over the window, the others can be just a rough shape. This second mask is the one to keyframe. With any luck the shoulder is not changing shape much and you might be able to just move the whole mask rather than the individual points(?). Don't keyframe every frame if you can help it (apart form the work, it can start to look very jerky), go through the shot and reposition the mask every 10th frame, then go back and reposition it every 5th frame where neccessary, then every 2nd frame if neccessary, etc. Make the mask with the minimum number of points you can - your current number seems ok, but only you know how much movement and change of shape there is - and don't worry about keyframing the points that aren't over the window area they can usually stay where they are. Don't use Roving keyframes, they will even out the speed of all the moves which you don't want. Only feather it if the edge is too hard, and the smallest amount that you can get away with 1 pixel, 2 pixels. There's nothing wrong with the way you are doing it but by using a seperate mask for the shoulder you may be able to save time by being able to reposition the whole thing. Trust that might help.