It looks like you've used mpeg2dec3 to pass YV12 directly to DivX. The DVD is chroma sampled as interlaced but DivX uses progressive upsampling for display, resulting in the artifacts. Maybe you used Decomb with postprocessing disabled and these scene change frames came through combed. If you get rid of all the combing you'll get rid of the artifacts. As Sirber requested, post your complete script file so we can determine the source of your problem and what you can do about it.