I tried again while Rhytmbox was running but it gives the same output:
ben@xameroth:~$ gdbus call --session --dest org.mpris.MediaPlayer2.rhythmbox --object-path /org/mpris/MediaPlayer2 --method org.freedesktop.DBus.Properties.GetAll 'org.mpris.MediaPlayer2.Player'
Error: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.mpris.MediaPlayer2.rhythmbox was not provided by any .service files
I tried again while Rhytmbox was running but it gives the same output:
ben@xameroth:~$ gdbus call --session --dest org.mpris. MediaPlayer2. rhythmbox --object-path /org/mpris/ MediaPlayer2 --method org.freedesktop .DBus.Propertie s.GetAll 'org.mpris. MediaPlayer2. Player' org.freedesktop .DBus.Error. ServiceUnknown: The name org.mpris. MediaPlayer2. rhythmbox was not provided by any .service files
Error: GDBus.Error: