[MEncoder-users] 2pass: auto-calculation of bitrate?

[Ilya Zakharevich]

I'm looking for a way to let mencoder (I use xvid) to automatically
select the 2-pass average video bitrate based on the contents.  I'm
pretty sure that most (if not the all) of the logic to do it is already
there, but I can't find the UI to trigger this behaviour.

A) For example: suppose I have 100 videos; now

  a) append them all together;
  b) do 2-pass encoding of them all with, e.g., 1200kb/sec bitrate;
  c) split the result into 100 video files.

This way, mencoder will automatically assign some "appropriate"
average bitrate to each video.

B) Now suppose that I have only 1 video, but I have all 100 logs of
pass=1 for all 100 videos.  Theoretically, this is all which is needed
to do an equivalent of a/b/c for this particular video.  How to
convince mencoder to use these extra log files?

C) Now suppose that I have only 1 video, and only 1 log of pass=1 for
this video.  It is more or less obvious that all I need from the
remaining 99 logs is very short "summaries".  How to create the
summaries, and how to "feed" them to mencoder?

D) And now the last logical step: If of these 99 remaining videos 40%
   is "action-like", 40% is "arthouse-like", and 20% is animation,
   then law of big numbers starts to be applicable.  Essentially, I
   won't need to have summaries of the particular videos; I could feed
   in 40 copies of "average action-like summary", 40 copies of
   "average arthouse-like summary", and 20 copies of "average
   animation summary".

So if I keep these summaries in ~/.mplayer in action.sum arthouse.sum
animation.sum, then I could ask mencoder to do

   bitrate_from=1200,40*action+40*arthouse+20*animation

and it could choose the appropriate bitrate.  Is it possible to do now
(possibly, with some pre-processing)?  Any plans to have this?

Thanks,
Ilya