NOTE: Almost all LOL samples (for TV) start at approx 5 mins - this could be 592 - 605 range, if the first doesn't work, back it up, or move it forward). Even though the rebuilt srs sample isn't correct (and will be artifacty), you will be able to determine where in the original it starts. In almost all I have seen, length is 60 seconds.

Basic format is

  Split a large video into small videos
      note the mb suffix in the -endpos switch:
      mencoder -ovc copy -oac copy -ss 0 -endpos 700mb -o movie_part1.avi movie.avi

But will use time, so format is
  mencoder -ovc copy -oac copy -ss 0 -endpos {nsecs} -o OUTPUT.avi SOURCE.AVI

Note, output file is first, source file is 2nd

I needed a good 61 seconds sample, so Cmd was:
  mencoder -ovc copy -oac copy -ss 0 -endpos 61 -o z.avi fringe.s0205.hdtv.xvid-2hd.avi


Another example:
  mencoder -ovc copy -oac copy -ss 301 -endpos 60 -o z.avi CSI.Miami.S08E18.HDTV.XviD-LOL.avi

This makes a 60 second sample starting at 301 seconds (5.01)