[MEncoder-users] Can mencoder be used to tell me whether a video contains high action scenes?

[David Smith]

 I am looking for a way to use Mencoder or Mplayer to analyze each video and
tell me whether the video contains a lot of action or movement.  If the vid
contains a lot of movement then want to program the converter to set
a higher bitrate (or other parameters).

I know that doing double pass encoding has something to do with the first
pass capturing information about each frame in order to help the second pass
encode it at a higher quality (that is all I really understand about two
pass encoding).  Would the file the first pass generates help me in this
matter?  If so, what would I write application code to "look for"?  What
is Mencoder looking at in the first pass anyway?  Thanks a lot.