You need to install some dependencies dependending wich encoding format you want to support.
Why do you want to install it ?
Is it for an home made script or for a cms script ?
If it's for a cms, i can do it for you.
If it's for an home made script, you can look my service :
PinkEncode - Plateforme automatisée d'encodage vidéos - mp4, flv, avi, watermark
You send via xml the videos to encode, i take it on your server, i made the encoding with your params, and i upload the result where you want.
You can use the xml response for aditionnal post-treatments