Would like to create some sort of mask during post to make a persons face look more towards the horror genre and wondered what would be the best way of doing this? It would only need a 2d image to animate over but wondered how to go about it?
Check out this video tutorial, might help: http://www.videocopilot.net/tutorials/demon_face_warp/
To summarize: You need to motion track the face and stabilize the footage with this tracking data. Good tracking points are the corners of the eyes, nose, etc (the new face tracker might help but I haven't used it much). Once your footage is stabilized you can apply whatever you want onto your actor's face. Then it is a matter of pre-composing everything and re-applying the motion to that precomposition.