Lyric Matte Operations
The Lyric Matte Operations filter doesn't produce a matte directly itself, but provides a set of useful operations on existing mattes and methods for constructing mattes from existing channels or other clips & images.
The Lyric Matte Ops filter includes a set of matte and output controls that are common across all Lyric matte filters. For a detailed description of these controls, please see the Matte Common Controls documentation.
For background information on mattes and their uses in Final Cut, please refer to the Lyric Matte Primer.
The Matte Source dropdown menu lets you choose the source of the matte to be the basis of this filter.
The selected source will become the new alpha-channel for the clip containing the filter, depending on the settings in the Output section of the controls, as described below. The first 5 items in the Matte Source menu take the matte from the selected channel in the source clip (the clip containing the filter).
The next 5 select from the same channels in the clip or image that is dropped onto the Mask/Image Clip well, allowing you to use a separate clip or image for matte. This is an alternative to using the Travel Matte composite mode on stacked clips in the timeline that gives more control, including the ability to adjust the matte using the Matte Levels & Matte Control sections of the filter, or mix it with the existing alpha-channel, and use it not just for compositing but also for filter masking.
Finally, you can force in an all-white or all-black matte, in case you need to override the existing alpha-channel in the containing clip.
The Invert and Fade controls in the Matte Source section allow initial processing of the selected channel before it is operated on by the following adjustment controls. Invert flips opaque to transparent and vice versa; Fade reduces the opacity of the whole matte.
The Matte Levels section contains standard Photoshop-like level & gamma controls. The White (opaque) slider sets the input white level, moving it to the left scales the whole matte towards white, increasing areas of opacity. The Black (transparent) slider does the opposite, setting the input black level and scaling the matte towards transparency as it is increased. The Gamma control sets the transfer gamma, essentially controlling the lightness or darkeness of the mid-tones, moving it to the left emphasizes the more transparent areas, to the right emphasizes the more opaque areas.
You can achieve the effect of a threshold control by setting the Gamma control to -100 and the White level to 255 and the adjusting the Black level. All input values below its current setting are forced to black (fully transparent) and those above to white (fully opaque). You can flip the sense of this pseudo-threshold control by checking the Invert checkbox in the Matte Control section.
The Matte Control and Output sections are common controls that are documented on the Matte Common Controls page.