By artifacts you mean the blockiness right? I'm not sure but I think the artifacting of mpeg 2 of retail dvds is mostly caused by bad single pass encode(r)s. If I encode my home movies with Cinema Craft encoder, use the right settings and a multiple pass encode there are absolutely no artifacts (and I film in 16:9 anamorphic). Also in my "fast scenes" with a lot of movement, no artifacts.