Nothing is there like only made for dvd players.
You can see the contents inside the DVDs.
Copy the contents to HDD & Try with VLC Media player.
Have you installed correct player for playing DVDs??
Sometimes the Movie discs you bought from shops may have some write errors with lead in/lead out problems. At that situation, a computer will struggle to read/recognize the contents of dvd, but a player will just play the movies, as the dvd player just require correct file format to play.