gaouzief - 10:02 am on Nov 27, 2007 (gmt 0)

Hello,
i think y're looking for ffmpeg (not sur i can post a link, so just google it)

it's an open source library that can transcrode pretty much any video format into another (including extensive output configuration like cropping, resizing, re-sampling, extracting thumbnails....)

it is in use in many web video services and has even a handy php extension (ffmpeg-php) so that you can programmatically manipulate your videos right from php

works on linux, windows and MacOs

Cheers,
Hassan