Plex is a fork of the original XBMC open source project that first became available in 2009.
Originally finding traction on the Mac as a media server, it has since been extended to Windows and Linux.
Perhaps the biggest contender is Kodi, which is the new name of the open source XBMC (Xbox Media Center).
XBMC started as a hack of the original Xbox, which was essentially a locked-down, Intel-based PC in its first incarnation.
It offers playback of just about any type of audio and video file, an extensive plug in architecture, heavy customization of the UI through skins, and the all-important DVR functionality with third-party TV tuners.
Despite these improvements, the focus in home entertainment shifted to consumer electronics (CE) devices.
The cost and simplicity of renting a plug-and-play DVR from the TV service providers outweighed the benefits of WMC, and streaming services starting around 2008 spread quickly to Blu-ray players and other devices that were easier to set up and maintain than a full fledged Windows PC in the living room.
It also offer the ability to feed cable or satellite video into the Xbox One and use Microsoft’s One Guide program guide.
But there’s no return of DVR functionality, or at least not yet.