UltraStar Deluxe is a free and open-source karaoke game for Windows, Linux, and macOS. It is based on the original SingStar™ game for the PlayStation®. The game allows up to six players to sing along with music using microphones in order to score points, depending on the pitch of the voice and the rhythm of the singing. Players are able to create their own songs and playlists, as well as choose from a selection of songs included in the game. The game also supports custom themes, backgrounds, and even video clips. In addition, UltraStar Deluxe allows players to compete against each other using an online scoring system.
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KaraFun
Performous
Karaoke Now!
Sing! Karaoke
Kanto Karaoke
iSing
KaraokeParty.com
Karaoke Player
cantafacil
Red Karaoke
Website discontinued and company site unavailable. For reference: https://www.thesun.co.uk/news/worldnews/5331072/karoke-copyright-payout-from-uk-firms/