Tutorial:Chroma Keying

Intro to Chroma Keying
Chroma Keying is simply the technical term for green screen effects. It works by taking a color of your choosing, then removing all instances of that color from a video clip or picture. You can then layer a different image or clip below the original. The second image will then show through where the color was removed. Unfortunately, this effect cannot be used in Windows Movie Maker, and more advanced software must be obtained before this effect can be utilized.

Basic Chroma Keying in Sony Vegas
One of the programs that can be used for chroma keying is Sony Vegas. If you are still new to Sony Vegas, a general tutorial for the program can be found here. The effect is really very simple to perform, and several video tutorials exist online to help further your understanding of the process. In this example, we will be giving Hitler a nice little red hat to wear in the office.
 * 1) Get your material ready and placed on the Timeline. Make sure the object to be chroma keyed is ABOVE the clip it will be laid over.
 * 2) Open the "Video FX" tab and select "Chroma Keyer" from the scroll menu. Since the background is green, click and drag the "Pure Green Screen" effect onto the clip. The green should disappear.
 * 3) Use panning and cropping to move the image to its desired location. Sony Vegas has a built-in tutorial that explains how to do this.

Advanced Chroma Keying in Sony Vegas
Sometimes, the background color isn't a pure green color. In that case, you're going to have to fiddle around a little more with the effect. Here, we're going to use a green screen Hitler, and give him a new background.
 * 1) Advance to step 2 in the sequence above, but don't close the pop-up window after you apply the chroma keying effect.
 * 2) Check the "Show mask only" box. Your goal is to make the areas you WANT to show to be highlighted white, and the areas you DON'T want to be highlighted black.  By fiddling around with the scroll bars in the pop-up window, you can fine-tune the effect to be perfect.  Before closing the window, uncheck the "Show mask only" box so that the clip will be colored again.