[MPlayer-users] cropping with mencoder

[Roberto De Leo]

Hi,
I am trying to crop an avi file using a line like

mencoder -ovc copy -aoc copy -vop crop=300:200 -o out.avi in.avi

but it does not work, i.e. I get in output exactly the file I give in input.
Is this due to the fact that I am using "-ovc copy"?
If so, is there any way to crop an avi without having to re-encode it?
I do not want to re-encode it, I just want to get rid of the black stripes!
If mencoder is unable to do it, do you know any other package that may 
be able to?
Thanks,
  Roberto