Cropping will almost always be necessary with live action content, as black bars are almost always applied to fit a 16:9 frame.
If the to-be-cropped content has a resolution that is a multiple of 2 in each direction, this is a very straightforward process:
crop = src.std.Crop(top=2, bottom=2, left=2, right=2)
However, when this is not the case, things get a little bit more complicated. No matter what, you must always crop away as much as you can before proceeding.
If you're working with a completely black-and-white film, read the appendix entry on these. The following only applies to videos with colors.
Then, read through this guide's
FillBorders explanation from the dirty lines subchapter.
This will explain what to do if you do not plan on resizing.
If you do plan on resizing, proceed according to the resizing note from the dirty lines subchapter.