LibreELEC!

Open Embedded Linux Entertainment Center (OpenELEC) is a small Linux based Just Enough Operating System (JeOS) built from scratch as a platform to turn your computer into a Kodi (previously XBMC) media center.

MythTV is a free, open source media center and digital video recorder (DVR) distributed under the terms of the GNU GPL. With its plugin architecture, MythTV can be transformed into a home media center suite, capable of managing your personal photo, video, and music collections, as well as keep you up to date with the weather, a ZoneMinder home security system, and much, much more.

VortexBox is a free, open source (GPL v3), quick-install ISO that turns your unused computer into an easy-to-use music server/jukebox. Once VortexBox has been loaded on an unused PC, it will automatically rip CDs to FLAC and MP3 files, ID3 tag the files , and download the cover art. Vortexbox will then serve the files to network media players such as Logitech Squeezebox, Sonos, or Linn. The music files can also be streamed to a Windows or Mac OSX system.

GeeXboX is a free and Open Source Media-Center purposed Linux distribution for embedded devices and desktop computers. GeeXboX is not an application, it’s a full-featured OS, that one can boot as a LiveCD, from a USB key, an SD/MMC card or install on its regular HDD. The GeeXboX distribution is lightweight and designed for one single goal: embed all major multimedia applications as to turn your computer into an HTPC. GeeXboX runs on x86, PowerPC and ARM devices.