I would like to convert a video in 16:9 format (1920*1080) to a 4:3 format (640*480) with Handbrake. Can anyone explain me what are anamorphic and modulus parameters? I tried to set modulus to 2 or 16 on a video but I can't really see the difference between both videos. I would also know if there are different algorithms to change a video resolution and if I am doing it in the right way. Bonus question: What are PAR width and height? They are set by default to 1, should I change them?