[MEncoder-users] mencoder 2 pass vs. 3-pass inconsistencies

[Nik Martin]

I'm using mencoder to make movies for my handheld (archos av500).
when i use 'real' 2 pass encoding using these comands in a batch file:

[code]

@echo off
del divx2pass.log
del frameno.avi
del tmprip.avi

rem save the dvd by getting it onto the hd as raw avi
rem mencoder -oac copy -ovc copy %1 tmprip.avi

rem a small delay to let all files flush, etc
ping localhost

rem video track (pass: 1)
mencoder -oac copy -ovc xvid -xvidencopts vhq=1:trellis:pass=1 -vf
scale=512:-2 temprip.avi -o NUL

rem aqnother delay
ping localhost

rem video track (pass: 2)
mencoder -oac mp3lame -lameopts mode=1:cbr:br=96:vol=7 -ovc xvid
-xvidencopts vhq=1:trellis:pass=2:bitrate=400 -vf scale=512:-2
temprip.avi -o "%2"

ping localhost
rem clean up
del divx2pass.log
del frameno.avi
del tmprip.avi

[/code]

using "the Big Lebowski" dvd as a reference, I get a nice, high
quality avi of 355 mb

if I  try to go for a 3 pass encoding, by ripping the audio first,
then 2 pass encoding the video, using -oac copy on both video passes,
I get a 635 mb video, that has a weird audio track, like one of the
audio channels is inverted, cancelling out the right audio channel.
any ideas?  I can post small samples of video on my website if it
would help any diagnosis.  in both files, the audio is reported to be
48 khz, and the video is reported to be 480-something kbps.