BLUR

[Steven L. gotz]

Use a track matte. Put the original clip on track one, then drop another instance of the same clip on track two. Apply the mosaic effect to track two’s clip. Create a track matte in a separate sequence (in 1.x – or the same sequence in version 2.0), apply the appropriate motion to it, then nest that sequence on track three of the original. Apply the track matte to track two telling it to use track three.

Or….

Instead of a track matte you could apply a garbage matte to track two instead.

Steven
http://www.stevengotz.com