MythTV is an open-source digital video recorder and media streamer software for Linux and Mac OS X. It is most often used in PCs as a free alternative to the popular TiVo service. It also has many of the network media streaming capabilities in Xbox Media Center. MythTV has almost all PVR functionality found with TiVo, including "Live TV" that allows you to pause, rewind, and fast forward live TV. It supports multiple TV tuners for multiple simultaneous recordings. Video is compressed using rtjpeg (from Nuppelvideo) or mpeg4 (from libavcodec). It is available as a free download, and is very often bundled with an Linux-based operating system for easy setup. One of the more popular MythTV bundles is Mythbuntu, a combination of MythTV and the popular Linux distro Ubuntu. The current release is version 0.21 released on March 8th, 2008.