*.ogm (Ogg Media)
About
Video format used by the game engine
Technical information
Programs
ffmpeg2theora
This package provides a command-line tool to encode/recode various video formats (basically everything that ffmpeg can read) into Theora, the free video codec.
FFmpeg
A complete, cross-platform solution to record, convert and stream audio and video.
Blender
Blender is a free and open-source 3D computer graphics software tool.