[MEncoder-users] problem encoding some files to xvid and mp3 audio (lame)

[Francisco]

Hi list, I'm trying to encode some files to xvid and mp3 audio using lame, so 
far so good, the problem es that some of the files are missing the last 
second or so of audio, I don't know the exact time, but it's obvious that the 
audio finishes abruptly. The strange thing is that most files are the same 
kind of source codec and all are being encoded to the same format, but only 
some of them have this problem.
The commands I'm using are the following:
mencoder -ovc xvid -xvidencopts 
bitrate=2000:me_quality=6:quant_type=mpeg:gmc:trellis:chroma_opt:vhq=4:pass=1 
-oac mp3lame -lameopts mode=0:cbr:br=64 <inputfile> -o /dev/null
mencoder -ovc xvid -xvidencopts 
bitrate=2000:me_quality=6:quant_type=mpeg:gmc:trellis:chroma_opt:vhq=4:pass=2 
-oac mp3lame -lameopts mode=0:cbr:br=64 <inputfile> -o <outputfile>

if I change "mp3lame -lameopts mode=0:cbr:br=64" for "pcm" the audio finishes 
ok, so I guess is something to do with lame.
lame: 3.96.1
mplayer: 1.0_pre7-r1
xvid: 1.0.3

That's all, any way to debug this problem?, since I have no idea how to do it 
really.
Thank you

Francisco