After Effects motion tracking/roto

[Steven Andrus]

Hey guys, i'm trying to fix some video with busy backgrounds by simulating a film-like depth of field. The way I was going to do it at first (and if I had hours and hours and hours this would be fine) is by making a bezier mask in After effects and then cutting out the subject, then compositing it over the original footage with some defocus effects applied to it. The result is amazing, the subject is in focus, foreground looks slightly out of focus, everyone is happy. The only problem is I have to, at times, go frame by frame adjusting my points for the mask shape by hand. Now if there was a way to use the motion tracker to track the points I would be in biz. Anyone know if this can be done? There's a plug in you can get called Silhouette Roto, but I downloaded the demo and I couldnt figure it out as it came with zero doc. plus it costs too much unless it really kicks... ...anyone know how to do this with the built in AE motion tracker?