Encode video FLV to AVI with one line

Just found on the Ubuntu forums a way to convert FLVs to AVI with a single shell line, using mencoder:

for file in *.flv; do mencoder -oac mp3lame -ovc lavc "$file" -o "`echo $file | sed -e 's/\.flv$/\.avi/'`"; done

Source is this thread.
However with gnome-mplayer it seems I can't always navigate the resulting AVI.