I'm using Acidrip (mencoder) to encode my DVD, and I'm using the LAVC codec. The problem I am having is when I do the autocrop and then encode the DVD, i get blocks along the bottom of the encoded video where there are motions. If I dont do any cropping , and just leave the black bars as it is, the video is perfectly fine. No blocks, smooth video. Another thing is, if I use the xvid codec and crop, I dont get the blocks in that either. Any ideas how to crop with the lavc codec with out getting blocks on the bottom of my video?

try ensuring that your cropping values are multiples of 16. acidrip doesn't check for this constraint as despite mplayer developers always maintaining this is nexcessay, mencoder normally rounds to a multiple of 4 anyway, and the outupt i've always found to be great.

sorry for taking to long to answer.