By Brian Chau:

I was asked today how to create a web page with transparent flash video like that in : http://www.livefaceonweb.com/samples.aspx

  1. Use a green/blue screen video with After Effects CS4. Do a chroma key with the Keylight effect.
  2. Render the video as flv (On2VP6) and make sure you select the “Encode Alpha Channel” box.
  3. Bring the flv into Flash CS4 and make an swf file.
  4. Add the swf into your web page using Dreamweaver CS4. And set wmode as “transparent.” BTW, Dreamweaver CS4 now has better code when importing swf.

Original article: http://brianchau.wordpress.com/2009/04/08/transparent-flash-video-overlay-on-html-page/