The FXScript Reference

This undocumented function returns the native size of a clip. Native sizes are something that's been missing from FXScript and difficult to work around. I discovered it in the source code to FCP 4's Widescreen Effect.

Essentially this is DimensionsOf for clips. Using these values it's possible to calculate the apparent zoom factor of the currently visible desktop preview.

To determine the zoom factor, divide the current width by the Native Width. That fractional value is the current zoom percentage. There may be some inconsistencies when RT is enabled.

Note that height values do not adjust for interlacing so values are total frame size and not field size. Use FieldProcessing if you need the height.

Unfortunately, it seems getNativeSize only works with standard input clips, ie clip1. Tests on several clips of various sizes dropped onto a clip input well, all yielded the same incorrect values.