Rotoscoping (Mask) This filter makes a snapshot of the frame before a keyframable vector based rotoscoping is applied. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply. Till Theato, Dan Dennedy Filter Alpha,Luma,RGB Mode Write on clear,Maximum,Minimum,Add,Subtract Alpha Operation Invert Feather width Feathering passes