If you are scaling an interlaced file to a different height, you can tell MPEG Streamclip to preserve interlacement and scale each video field separately by checking "Interlaced Scaling". If you don't, interlacement will be lost in the scaled movie, and you get many visual artifacts. So now MPEG Streamclip 1.5 can convert also DV material 4:3 <-> 16:9 while preserving interlacing! It can do the conversion with letterboxing or without letterboxing (but with cropping, of course). For more details, check: <http://www.sjoki.uta.fi/~shmhav/SVCD_on_a_Macintosh.html#43-169>