DivFix++ is an open source AVI video repair and preview software which works on Windows, Linux and Mac OSX. It was designed for repair and preview of files downloaded from bittorrent, gnutella, emule, ftp, web or any such source and it can repair AVI and DivX files (for now).
Sometimes when you watch a move, the sound is just too low, even setting your alsamixer to 100%. But you can increase your MPlayer soft volume to 300% with just a simple command.
Let's say you downloaded some videos of Youtube which all are a part of a larger video that was splitted into parts. A good idea would be to join those video files into one big file. Here's how to do that in Linux: