Thanks I was a big fan of spmc and I tried to install MrMC but as the shield has an unlocked bootloader it seems it is not compatible... And I need root :(
On Plex if a movie is in DTS and your amp (or Sonos in my case) do not support DTS there is no sound... as Plex see DTS as supported by the Shield so do not convert it in 5.1...
Thanks again for your great work