I'm converting with this:
mencoder "$FILENAME" -o "$OUTPUTFILENAMEINPROG.avi" -ovc x264 -x264encopts bitrate=450 nr=2000 vcodec=mpeg4:mbd=2:mv0:trell:v4mv:cbp:last_pred=3:predia=2:dia=2:vmax_b_frames=2:vb_strategy=1:precmp=2:cmp=2:subcmp=2:preme=2:qns=2 -oac mp3lame -lameopts cbr:br=128 >/dev/null 2>&1
but if it get's interrupted, how can I continue where I was? converting again the full video to that point where it got corrupted takes too much time..