This filter is co-authored by Donald Graft and Avery Lee.
Focus X and Focus Y These edit boxes specify a point in the source frame that will be maintained in the center of the output frame. This allows you to create a zoom focused on any point in the source frame. Note that with some zoom settings, a focus set away from the center may result in the filter attempting to display an area outside the source frame. In such a case the filter will fill that area with a smeared copy of the nearest valid pixels.
Start percent and End percent These edit boxes specify the beginning and ending zoom factors. The Phase 1 controls define the behavior of the first zooming phase and the Phase 2 controls define the behavior of the second zooming phase. To disable the second phase, enter the value 0 for the start percent. If the start percent is less than the end percent, that is a zoom in. If the start percent is greater than the end percent, that is a zoom out. If they are the same, why are you bothering with this filter? :-)
Start frame and End frame These edit boxes specify the range of frames over which the zoom effect will occur. The Phase 1 controls define the behavior of the first zooming phase and the Phase 2 controls define the behavior of the second zooming phase. For frames prior to the phase 1 start frame, the specified phase 1 start percent is used. For frames after the phase 1 end frame but before the specified phase 2 start frame, the specified phase 1 end percent is used. For frames after the phase 2 end frame, the specified phase 2 end percent is used. For frames between the start and end frames (inclusive), a perspective zoom is implemented.
Fill red, Fill green, and Fill blue These edit boxes specify the fill color to be used when the source frame is zoomed down to a size smaller than that of the output frame.
Interlaced Check this option if your source is interlaced.
Filter mode This drop-down list selects the resampling method.
This version adds a second configurable zoom phase and corrects a bug in the scripting support.
Version 1.1 corrected a bug in interlaced mode support.
Version 1.0 was the first released version.