I'd like to reproduce this effect:
I'm reasonably familiar with After Effects, but I've only dealt with Mocha tracking, masking, text animation, and cameras, never with split screens. One of the biggest problems I've had is simply getting the effects to align properly. I've tried to "build out" each small screen with a new layer, but it's become very tedious to get it to align to the exact pixel. I'm also not sure how to build the white border...sometimes in motion, sometimes not.
Any guidance would be appreciated...I haven't been able to find an appropriate tutorial. (I'm a member at lynda.com, if you know of something there I haven't seen.)
The trick here is nothing more than layer order and duplicate masks. Draw a mask that splits your image in half for example, then copy the mask and paste to a new layer or duplicate the layer and set the mask to invert. The white stroke can be created with Stroke or a shape layer. The other ide would be to layout your grids in Illustrator using a solid fill and line for the white stroke on separate layers, then import as a comp, add your footage between the appropriate layers, set the solid shapes as track mattes for the footage, parent the track mattes with the footage and animate from there.
The other option would be to simply make some guides to draw your masks with the pen tool, copy and paste the masks on a new footage layer and choose invert.
Guides would help you align the stroke effect also. It's all pretty simple, it just takes some planning.