Cutting a moving object out of a video

[jem313]

I was wondering how to cut a moving object/person out of a video and superimpose them onto a different background. I can manage to make a mask in abobe after effects that separates the object from its original background but when it starts to move I can't figure out how to change the mask to compensate for the movement without messing up the beginning.

I need suggestions on how to perfect the way I'm doing it now or hopefully a better way

[wkulecz]

IF what you want to do was easy it wouldn't cost as much to make a Hollywood movie as it does to launch a typical Mars space probe.

Basically you redo the mask one frame at a time or you "cheat" and record your moving subject against a blue (best for analog) or green (for DV) background ("screen") and use chroma-key effect to remove the solid color background. This doesn't work if the object has anything the same color as the screen or if the screen is not very evenly illuminated.

Elite Video sells background screens that are supposedly the "optimum" shades of blue or green.

--wally.

[hippie91]

i know you can also buy straight up cans of the right color paint to make your own screens/rooms/furniture........

if you do use a blue/green screen make sure that you light it seperately from the subject, and make sure that the lighting on the screen is completely even, else when you try to key it out it won't be a solid color and will give you problems