
It is important as 4/3 has non square pixel (different for PAL and NTSC) and if you do 1:1 -> 1:1 you will end up with distorted image. If you do DVD2Divx for example, source is 4/3 or 16/9 and destination is 1:1.

The resize filter is a port to YV12 of avisynth resize filter. It won't work very well on a noisy source (capture) On a clean video (dvd), you can try the Autocrop button. You can preview the part that will be cropped using the Apply button. The cropped value left/right/top/bottom must be even. This filter crops the video (for example to remove black border).

This set of filters deeply alter the source video : Resize, rotate, flip and crop.
