[MEncoder-users] So does "target size" in xvid actually do anything?

[larrystotler at netscape.net]

-----Original Message-----
From: Padraig Hogan <padraig_hogan at yahoo.com>

>I steered clear of target size before, but I thought I'd give it
>another go. This time I would encode the audio first and then the 
video. The
>following is the relevant part of my batch file: 

Target size would ignore bitrate from what I remember.  However, some 
movies I've done ended up smaller due to less need of bitrate(I encode 
at 1536, but I have some that only  "needed" 1100).

>if %2==2 "C:\mencoder\mencoder" %1 -oac mp3lame -lameopts abr:br=128 
-ovc copy -o %1.btw

Why not use mencoder for the audio?  Is your mencoder compiled with 
mp3lame support?  Also, mp3lame is only stereo, so if you want 6 
channel, you shouldn't encode with mp3lame(found that out the hard way 
after a friend assured me mp3lame did 6 channel).

>if %2==2 "C:\mencoder\mencoder" %1.btw -oac copy -ovc xvid 
-xvidencopts
>bitrate=-1024000:threads=2 -vf scale=720:-2 -sub %filename:~0,-4%srt"
>-utf8 -subfont-text-scale 2.7 -o %1.avi
>del %1.btw

I've found that "threads=" in xvid is pretty useless.  It's not very 
good at multithreading.  I can re-encode 2 movies at the same time MUCH 
faster on a dual core than using threads and doing them 1 after the 
other.  xvid gets maybe 20-30% faster.  x264 is MUCH better at 
multi-threading than xvid.

>But it still just completely ignores the 1024,000 kb and it comes out 
as 800mb.

Probably because it only needs 800k for that file.  What's the original 
source?  mpeg2?  And why not do 2 pass on xvid?  Use "pass=1,turbo" for 
the first pass and you will see much better quality.

>I've had similar problems with it before. It's almost as though it 
doesn't even
>matter what size you put it, mencoder will just choose it's own size 
that's
>around 750mb for a typicalk movie.

here's a handy calculator for calculating xvid bitrates and sizes:

http://quadpoint.org/projects/simplerip#audio_and_video_bitrates

a 1 hour 30 minute movie at 700mb only needs a bitrate of 953 to get a 
700MB file with 128kb/s audio