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

[Ilya Zakharevich]

[A complimentary Cc of this posting was NOT [per weedlist] sent to
James Hastings-Trew 
<mencoder-users at mplayerhq.hu>], who wrote in article <4928DF92.3050701 at shaw.ca>:
> Mmm.. no, I suggested a sub-sample approach, which has worked out very 
> well for me, in practice. It takes about 2 minutes to take several 
> sub-samples of the movie at regular intervals and derive a target 
> bitrate based on the results, followed by a one-pass encode that gives 
> very good results, fairly close to the target file size, in a reasonable 
> amount of time.

Consider yet another corollary of such a wizardry: to do this, you
should be able to easily recognize the encoding defects.  However, for
most users, such a wizardry carries a very strong NEGATIVE benefit ratio!

For example, with my level of audio expertise, I can easily enjoy
sound from well-below-$1000 equipment.  I do not doubt that even in my
age, my hearing is good enough so that I can educate myself to hear
defects in my equipment.

But what is the value of such an education?  The only value is that I
will need to spend another $9000 to upgrade my equipment to $10000 one
- and I still would get "the same" enjoyment from the new equipment.

So consider a user who:

   a) does not want/can't learn recognition of what is good/bad encoding;

   b) wants to encode in such a way that his guests won't hurt when
      they see the image (even if they are more expert-like).

How should they choose the bitrate?  A way to automatically choose
bitrate for different sources basing on some output criteria (like
lame --preset options) would be very beneficial.

==================================================

All I did in the initial postings was I noticed that mencoder ALREADY
has something similar: with 2-pass, it chooses different bitrate for
different "segments" of a video.  So do the same for different FILMS.

Concatenate 50 films, and run 2-pass encoding over the result; then
cut the result into individual films.  Would not different films be
encoded with "similar quality"?

Thanks,
Ilya