chromakey movie

WARNING:
PLEASE DOWNLOAD AND TEST THIS PLUG-IN BEFORE PURCHASING IT. WE HAVE RECEIVED REPORTS OF INCREASED INCOMPATIBILITIES WITH NEW SYSTEM UPDATES, AND IT APPEARS THAT THE PROBLEMS ORIGINATE OUTSIDE OF THE PLUG-IN.

what is it?
this iMovie plug-in is billed as the “best-of-class compositing ('blue-', 'green-screening') plug-in”. but what does it do? simply put, it allows you to intelligently blend two movies dynamically. this usually involves much more than using simple transparency masks because it allows you to target any color in one of your movies and make that color transparent. in tv, the color usually replaced by a picture usually is blue or green, hence the name 'blue/green screening' (the actor stands in front of a blue or green screen). the best known (and probably most often) example for this technique is the newscaster in front of the white house. the process of intelligently combining two picture sources is also sometimes 'compositing'. the technique of replacing a key color with a whole picture is also called 'chroma keying'.

note:
there is a spcialized plug called ‘chromakey static’ that works with a movie and a picture. this plug also works with pictures - but if all you want is compositing pictures and animated material, you should work with the ‘chromakey static’ plug.


 

price : USD 3.50

version 2.0.0

features

opacity slider
this controls the overall opacity of the effect, allowing you to blend the result back with the original effect (this is required for some advanced masking. don't worry if you don't need it).

configure dialog:

red source rectangle
this rectangle defines the area that will contain the second source (a movie or picture). all compositing is limited to this area. to re-size the rectangle, click and drag the handles. to re-position, click and drag inside the rectangle.

chroma key color

when using arbitrary color keying, this defines the color that will be regarded as invisible (= white color in the mask).

movie button
click into either to assign the second source. you may use any movie or picture format the Mac knows. if you use a picture with an invisible color, the invisible parts will be filled with the ‘background’ color (see below).

keep prop’s
if this box is checked, re-sizing the red still source rectangle will force it to have the same proportions as the original picture/movie.

background color
when not using a second source or using a second source with invisible colors, this color will be substituted for the empty parts.

clip slider
use this slider to pre-view the clip source. using this slider allows you to cue to any frame in the clip. this may be necessary to find the correct chroma keying color.

show picture preview
when this box is checked, the red source rectangle will show a preview of the source. if unchecked, only the source frame will be displayed. if you have chosen a movie, only the first frame will be shown in preview.

select all
when you click this button, the red frame will expand to exactly match the whole clip’s area.

chroma setup
clicking this button will take you to the ‘chroma setup dialog’ (see below).

 

chroma setup dialog:
the croma setup dialog is an intuitive, yet highly specialized dialog to help you set up, and tweak, the dynamic mask that accomplishes the digital compositing (for an deeper understanding of how this masking works, please read the ‘using cf/x chorma key’ section, below).

clip source
this little square shows a preview of the currently selected clip frame. any mask pixel (see below) that is black will be taken from this source.

use clip as source
clicking into this button will tell the plug to generate the mask (see below) from this source.

movie source
this little square shows a preview of the currently selected second source. If the plug is configured to use only part of the screen (i.e. the red source rectrangle doesn’t cover all of the clip’s surface), the remainder is filled with the background color. any mask pixel (see below) that is white will be taken from this source.

use this as source
clicking into this button will tell the plug to generate the mask (see below) from this source

method pop-up
this pop-up determines the method that is used to create the mask (see below). this plug comes with the following pre-defined methods:

color:
any pixel that matches the defined chroma color (displayed in the box to the right) or is close enough in chase the ‘thresh’ slider is used (see below) will result in a white pixel in the mask. All other pixels will result in a black pixel in the mask.

red, green, blue:
any pixel whose red (green, blue) color strength exceeds the ‘All or’ slider will result in a white pixel in the mask, else it will result in a black pixel. if the ‘All or’ slider is set to zero, the channel will be used as a direct transparency map.

brightness
any pixel whose brightness exceeds the ‘All or’ slider will result in a white pixel in the mask, else it will result in a black pixel. if the ‘All or’ slider is set to zero, brightness will be used as a direct transparency map.

 

chroma thresh / level slider
this slider is used differently depending on the currently selected method.

color:
the slider determines how closely a pixel must match the chroma color to generate a white pixel in the mask.

red, green, blue, brightness
the slider determines at which value a pixel in the mask goes from white to black.
the zero position has a special function: it uses the selected method channel as a direct transparency mask. when using a bluescreen this can be used (with the blue channel of course) to make the actor cast shadows onto the substituted source.

 

mask preview
this square shows a preview of the current mask. it is instantly updated to reflect any change you make to any other setting.

invert mask
checking this box will result in the mask being inverted. A black pixel becomes white and vice versa.

result preview
this square shows a preview of the resulting composition process.

post-processing pop-up
our plug supports multiple mask post-processing strategies aimed at eliminating color spill when using blue-/white-/green-screening (when using a still frame as source for a mask, you should not need this).

the following strategies are available:

none
the post-processor is switched off

enlarge white
this processor employs an edge-detection algorithm and enlarges the white areas of the mask.

enlarge black
this processor employs an edge-detection algorithm and enlarges the black areas of the mask.

x-fade white
this processor employs an edge-detection algorithm and uses the white areas of the mask for a cross-fade.

x-fade black
this processor employs an edge-detection algorithm and uses the white areas of the mask for a cross-fade.

smooth
a simple algorithm that smoothes white/black contrasts in the mask

tri-minimum
a second, simpler strategy for enlarging black areas in the mask

tri-maximum
a second, simpler strategy for enlarging white areas in the mask

tri-average
a second, simpler strategy to smooth the mask

 

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