Usage guide for Compositing with Carbon or MuxMan Alpha Processor (Keyer) Tab Controls
These controls create or modify the Alpha Processor filter attached to an image.
From top to bottom, left to right:
Filter - selects which one of many possible filters active at the current time.
Start - sets the time when this filter becomes active, relative to the element's display time.
Duration - sets the duration of the filter.
New - used to create a new Alpha Proc which starts at the current time.
Positioning - used to offset the generated alpha channel data in the x and/or y direction.
Key Source - selects the image or object which will be used to form the alpha channel data.
Currently the only data that can be processed from the key source is its alpha channel.
Delete - removes the currently selected filter.
Opacity range - sets the minimum and maximum opacity values for the generated alpha channel. This is used to scale the
data from the key source. Note: By reversing the min and max values an inverse mask can be produced, there is also a checkbox for inverting
the mask. If both are used a non-inverted mask is created.
Edge softness - the value is approximately the number of pixels in either direction based on the final mask dimensions of blurring to be applied
to the edges of the mask.
The options checkboxes:
Invert mask - see above "Opacity Range"
Add to mask - more than one Alpha Proc filter can be active at a given time, if this checkbox is not checked this filter will further decrease the
opaque areas. If checked this mask will be added to the previous mask(s) to add to the opaque area.
Limiter - if selected the opacity values of this mask will be prevented from exceeding those of the image being filtered. This is used to prevent
additive filters from increasing the opacity of any pixel.
Key starts at time 0 - if the key source is a motion object, such as a transition mask, which can be used at any point in the timeline checking this
option will override the current time value with 0 before drawing the key source.
Key duration from Keyer - if the key source is a motion object checking this option will override the duration of the motion with the duration of this filter.
Run transition in reverse - if the key source is a motion object the time passed to the drawing function will be altered to cause the motion of the key
object to run backwards.
Mask type dropdown - selects resizing options for the mask as follows:
center actual - disregards the position values of the key source so that regardless of where the key source would appear in the composite it is centered
before applying the offset (see above "Positioning"). The size of the mask is the actual size of the key source as it appears in the composite.
follow key - the mask will align with the key object in the composite prior to applying the offset, and be actual size.
Virtual mask - the mask is resized as if the image being filtered is the entire composite.
full size - the mask is centered prior to applying offset and resized to the dimensions of the image being filtered.