#!/bin/bash
vcodec="theora" 
acodec="vorbis" 
bitrate="500" 
arate="64" 
ext="ogv" 
mux="ogg" 
vlc="vlc" 
fmt="avi" 

for a in *$fmt; do 
$vlc -I dummy -vvv "$a" --sout "#transcode{vcodec=$vcodec,vb=$bitrate,acodec=$acodec,ab=$arate,channels=6}:standard{mux=$mux,dst=\"$a.$ext\",access=file}"vlc://quit 
done