[MPlayer-users] Bitrate filesize problem (2)

rcooley rcooley at spamcop.net
Fri Feb 7 18:56:04 CET 2003


The problem I'm experiencing is that the vbitrate which SHOULD give me a 
700MB file is giving me a 586MB file instead.  I've searched the 
archives (as well as Google), but get tons of unrelated results.  I'm 
using a 2-pass method, which is really just the three-pass method 
described in the docs, without the final (3rd) pass. (no point in a 
third-pass when I know the size is wrong in the second-pass)

The commmands for each pass (verbatim) and some extra information follows:

Pass-1:
mencoder -alang en -dvd 4 -lameopts q=9:mode=1 -lavcopts 
vcodec=mpeg4:vbitrate=1000000:vhq  -oac mp3lame  -vop crop=718:432:0:24 
-ovc frameno -o frameno.avi

Which gives me a nice audio file: 145M    frameno.avi
And the final message:
__

   Writing AVI index...
   Fixup AVI header...
   Recommended video bitrate for 650MB CD: 479
   Recommended video bitrate for 700MB CD: 526
   Recommended video bitrate for 800MB CD: 621

   Video stream:    0.766 kbit/s  (95 bps)  size: 846164 bytes  8834.664 
  secs  211541 frames

   Audio stream:  123.371 kbit/s  (15421 bps)  size: 136250256 bytes 
8835.168 secs
__


Pass-2:
mencoder -alang en -dvd 1 -lameopts q=9:mode=1 -lavcopts 
vcodec=mpeg4:vbitrate=526:vhq -oac copy -vop crop=718:432:0:24 -ovc lavc 
-o Apocalypse\ Now.avi


And I have a file that is far too-small: 586M    Apocalypse Now.avi


The entire, gzip'ed output of each of the passes (in case that output 
will be useful to anyone) is available here: 
http://geocities.com/ryancooley/mplayer/bitrate-problem/


(I realize I included unnecessary information in the command-lines, but 
it's just easier that way.  Doing it without the extra info doesn't 
change a thing.)

I'm using MPlayer 0.90pre6-2.95.3 on OpenBSD 3.2, but I saw the EXACT 
same behavior with 0.90pre8 on FreeBSD 4.7.

In addition, it isn't just the "-vo frameno" bitrate that is 
incorrect... all the bitrate calculators out there give similar values, 
which result in the same problem.

I *really* appreciate any help, as not being able to accurately estimate 
the best bitrate wastes countless ammounts of time and energy (for both 
myself and my system).



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