This was first posted in another thread and was well received. Given that and my lack of ability to post to a Tutorial forum I'm making this a \"sticky\" so it'll remain readily available.
Ever see the effect where just the silhouette of a person is moving across a background with a video playing within their transparent body? Here's how to do it;
First film the subject in front of a white screen. If it's already a greeen/blue screen overlay it on a white background and export it with the white backgrond. This will be your overlay clip;
Now place the clip you want to show through on Va or Video1, depending on the MSP version you're using. Next place the overlay on V1 or Video2 (version difference again) and apply a luma key to remove the background. Now reverse the key by checking the \"Invert Overlay Area\" box. This will cause the background clip (Va/Video1) to show through the foreground subject and the overlays white background to be displayed again;
Rendering this out will give you a white background with the now transparent subject and your background showing through him/her/it.
Overlay this clip using a luma key on other footage and you'll have that original background in the shape of the original subject dancing around a whole new background;
Poof.
http://digitalvideo.8m.net/ghosteffect/shadowgirl.wmv (270k)
Here's an alternative for use in MSP8's nested timelines when the \"dancer\" source is a green/blue screen clip;
1. load your final background to Video1 on the main timline.
2. create a new timeline; timeline1. Place the \"dancers\" background clip on Video1 and the green/blue screen \"dancer\" clip on Video2.
3. set the \"dancer\" clips overlay options to chromakey and adjust similarity to just erase the background. Now reverse the key as before. The background will show through, but with the original green/blue background.
4. go back to the main timeline and insert timeline1 as a virtual clip. Now apply a chromakey to it in the overlay options and adjust the similarity.
Poof2 and you don't need to render a file.
Starting with footage that is in front of a complex background would require creating a video matte in Video Paint using the Macro function and perhaps the Ruby Mask mode. Tedious and it will take some manual reading, but its effective.