I just encountered this the other day too. PS4 DOES support Atmos and DTS-X. There are two places you need to change the audio output, first in the audio output settings for the system you need to set it to bitstream. ALSO, when you insert a movie, you need to go to options once the disc is playing (PS4 options, NOT the disc menu) and make sure it is also set to bitstream. I had mine set to bitstream for the system but when I played a disc, I noticed it wasn't the correct audio so I poked around the menus and found that settting then it worked.