[hello_hello]

One of the reasons I resize, is because the script adjusts the cropping to prevent aspect error, so you can do something like this to crop extra black for a scene, and the script will crop a bit more as required so you don't have to worry about aspect error.

Trim(0,999).CropResize(640,480, 14,4,-16,-4, InDAR=15.0/11.0) ++ \
Trim(1000,1999).CropResize(640,480, 14,4,-48,-18, InDAR=15.0/11.0) ++ \
Trim(2000,0).CropResize(640,480, 14,4,-16,-4, InDAR=15.0/11.0)

You can go with a "least amount of resizing" resolution for the majority of the cropping, and still know for the sections where the cropping needs to be changed, the picture won't be distorted.

But I invariably resize, especially DVDs, as I always resize to square pixel dimensions.

Edit:

or....

Trim(0,999).Crop(16,4,-16,-4) ++ \
Trim(1000,1999).CropResize(688,568, 14,4,-48,-18, InSAR=12.0/11.0, OutSAR=12.0/11.0) ++ \
Trim(2000,0).Crop(16,4,-16,-4)

would allow you to easily crop some extra and resize a section to match the rest, once again without having to worry about aspect error.