"Mencoder is part of the MPlayer media player package. While
MPlayer can play audio and video files, mencoder converts and
manages multimedia files. The application has a ton of graphical
user interfaces, but you can use it from the command line to
produce video files in almost any format you want. Here's how.
"Among the file types mencoder can handle are MPEG/VOB, AVI,
ASF/WMA/WMV, RM, QT/MOV/MP4, Ogg/OGM, MKV, VIVO, FLI, and FLV. The
command syntax is straightforward despite a wealth of options.
There's little mencoder can't do when it comes to multimedia