SetPixel/GetPixel in Flash MX

[size=1]Hi! I am trying to make a flash program that can load a video file or webcam or such thing; and then dynamically edit it; blue screening for example.[/size]
[size=1][/size]
[size=1]So, I want Flash to find pixels of a certain color and replace them by another picture/video file. The issue is I cant find any function to do this? I have an idea how to do this in Visual Basic. Would there be a way to have VB edit the video and send it back to Flash in real time??[/size]
[size=1][/size]
[size=1]Thanks so much!!
Jay
[/size]