OK, I'm totally lost? Are you referring to Samsung TVs that have built-in media player? Otherwise, what difference would it make if connecting through HDMI? The player you're using would decode XVID or DTS audio, whether it's a media player, PC, or Bluray, before sending the signal to the TV?
DTS is still in use though in the theater world is known as DataSat. It's the only digital sound solution for 70MM film, Dolby has no 'digital' solution. It was used not too long ago in movies such as 'Dunkirk' and 'Hateful 8' 70MM Ultra Panavision. Both releases in Bluray use DTS-Master audio.
Though XVID may be open source, is uses patented technology. In which case, there would likely be a license fee required to patent holders for commercial use applications?