Snapcast app
Snapcast is Multimedia tool that is open source under the GPL-3.0-or-later license. Multi-room client-server audio player, where all clients are time synchronizedwith the server to play perfectly synced audio. It's not a standalone player,
but an extension that turns your existing audio player into a Sonos-like
multi-room solution. The server's audio input is a named pipe /tmp/snapfifo. All
data that is fed into this file will be send to the connected clients. One of
the most generic ways to use Snapcast is in conjunction with the music player
daemon (MPD) or Mopidy, which can be configured to use a named pipe as audio
output.