The Chroma Key button and its associated menu item let you composite a foreground movie over a background movie according to color values in the foreground movie.
To composite a chromakey movie over a background movie, start by opening the background movie normally, using the Open command from the File menu.
Once the background movie is open, the Open Foreground Movie menu item will be enabled, allowing you to open the foreground chromakey movie.
A chromakey foreground movie must be a 24-bit movie.
The background movie can be either 24 or 32 bits deep. The new movie created by this function will match the bit depth, frame rate and length of the background movie unless you select different settings in the Compression dialog when starting the process.
If the foreground alpha channel movie is shorter than the background movie, it will disappear when itﾕs finished, and the background movie will continue until itﾕs finished.
Once both movies are open, select the Chromakeyﾉ item from the File menu or click the Chroma Key button in the main window.
MoviEffects will open a palette that provides a set of control for adjusting chromakey settings.
The chromakey function is designed to work from a reference frame that is completely clear, showing only the chromakey background color. The reference frame can either be the first frame of the foreground movie, or you can load a movie or a PICT file as the reference. If you load a movie, the first frame will be used as the reference frame. If you select the ﾒLoad Ref. Frameﾓ button, the ﾒOKﾓ button will change to read ﾒLoadﾓ. Once you load a reference movie or PICT, the button will change back to ﾒOKﾓ, and the reference option buttons will be disabled.
The chromakey function can also work without a reference frame, although the results will probably not be as good as with one, and the process will operate much more slowly. We strongly recommend using a reference frame; the ability to work without one is provided simply for completeness.
The Chromakey palette also has text fields for Hue, Saturation and Brightness, along with fields for Hue, Saturation and Brightness Tolerance settings. If you move the cursor to the preview display, it will change to an eyedropper. You can click anywhere on the image to set the Hue, Saturation and Brightness settings, and the type in a range for Tolerance.
You can also click and hold down the mouse button to drag over the image to set a Tolerance. While you drag, MoviEffects will track the high and low Hue values to compute a Tolerance setting. When you release the mouse button, the Hue value will be set to the middle of the Tolerance range. When you click the OK button, MoviEffects will open a file save dialog.
MoviEffects will automatically append ﾒ.Compﾓ to the original file name, but you can rename the file if you wish. When you click on the Save button in the file dialog, MoviEffects will begin compositing the alpha channel or chromakey movie over the background movie. At the bottom of the window it will show the frame numbers it is currently processing.□□□□□□↵□□□□廖□u0□□↵□□□□□□□□□□□□□□↵□□□□□□□□□□□□□□↵□□□□□□□□□□□□□"↵□□□□□□□□□□□□□&↵□□□□□□□□□□□□□8↵□□□□□□□□□□□□□<↵□□□□□□□□□□□□□k↵□□□□□□□□□□□□□\↵□□□□□□□□□□□□□ﾟ↵□□□□□□□□□□□□□é↵□□□□□□□□□□□□□□↵□□□□□□□□□□□□□□↵□□□□□□□□□□□↵□□□□□□□□□□□↵□□□□□□□□□□□□□S↵□□□□□□□□□□□□□W↵□□□□□□□□□□
