Hey, I got the answer (at least for wmv files) from the mencoder maillist....

> If you add the framerate options with wmv, the problem gets resolved.
> -ofps 24
> Also, as previously stated it is no longer necessary to dd the
> -lavfopts i_certify_that_my_video_stream_does_not_use_b_fram es
So here's the command I issued, and it created a perfect WMV file:
Code:
/usr/local/bin/mencoder /home/thewall_net/public_html/video/163.wmv -o /home/thewall_net/public_html/flvideo/003.flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=700:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 -srate 22050 -ofps 24