MythTV is a Linux application which turns a computer with the necessary hardware into a digital video recorder, a digital multimedia home entertainment system, or Home Theater Personal Computer. MythTV is free software licensed under the GPL. It can be considered as a free and open source alternative to Microsoft Windows Media Center, although MythTV itself predates Microsoft Windows Media Center.
The default file format for software encoding is a RTJPEG or MPEG-4 video stored in a slightly-modified version of Roman Hochleitner's NuppelVideo (.nuv) container. MythTV used the libavcodec codec library and libavformat container library from the FFmpeg project.