I have HD 1080 50I clip encoded from EDIUS canopusHQ (4:2:2), I want downcovert it to PAL SD or mpeg, I try many NLE softwares such as Premiere pro 5.5, Edius 6, and TMPGEnc Video Mastering Works, but the quality of the image is not good, how can i downcovert HD to SD with best image quality? what software can i use? or what measures can i use to do it?