Adding two videos to each other (vertically or horizontally)

[Omni]

well i tried to search for it but didn't find a solution (sorry if i've overseen a previous post concerning this)
I want to add two video streams so that there's one resulting stream where both videos are visible at the same time. the one above the other (2*740x80 = 720x960)
and is it possible to determin the length of a file (length in frames)
i want the longer file to be cut equally on both ends.
thanks in advance!

[jellysandwich]

http://www.avisynth.org/Stack

js

[mg262]

StackHorizontal, StackVertical (cf documentation for these); length of a clip is FrameCount(clip).

[tedkunich]

Wouldn't STACKVERTICAL do what you want? You will have to pad the shorterclip to be equal length.