[Chris Ferriola]

Rotoscopeing is probably the only option, however using Mocha for AE will help save a lot of time.
If you select the video layer in your AE comp, go to the “Animation” tab at the top of the screen and select “Track in Mocha AE” This will open the video clip in Mocha. You can roto everything in here and then copy/paste or export the data back to AE to be used as a shape layer or masks.
Good Luck!

Chris Ferriola
Co-Founder/Animator
3 Dart, llc
http://www.3-dart.net