Hi, recently I been ask if the process of 3 D top/bottom as the same to side by side my answer was yes but I thought make a post about it.
I've grabbed a trailer like this, http://www.youtube.com/watch?v=WMpHgdG4VC8&feature=related
and see who that end.
the system is Ubuntu 12.04LTS and Avidemux 2.5.4 64bit,
after imported the video file to Avidemux, 2 motion pictures
filters under video tab, first crop
the crop preview
the green area is what will be cut off
after crop you will end up this preview
resize filter use avisynth to bring back to the size of 1920x1080
this trailer is 1920x1080 after crop is 1920x400
video filter tab crop and resize
the resize (1920x1080) preview
finally re-encode this trailer.
trailer: The Pirates! Band of Misfits
other posts: http://insideofasmallbox.blogspot.co.uk/2010/12/encode-3-d-to-2-d-in-avidemux.html