Apple Compressor 3 - Manual (Page 291)

3 Click the Geometry tab in the Inspector.
4 Enter your source inset (cropping) settings, choose output size dimensions from the
Frame Size pop-up menu, and choose padding settings from the output image inset
section.
You can see all changes you make to your setting by viewing the Summary table in the
Summary pane.
291 Chapter 24 Adding Geometry Settings