Just installed Plex mediaserver on Windows 10 and the app on a PS4. The PS4 reports a 7.1 audio setup is detected and output is set to PCM. I use a Pioneer VSX-922 receiver with 7.1 speakers.
When playing movies with any kind of surround sound however, the rear surround speakers always remain silent. When playing 5.1 surround, only the surround speakers are used. Normally, when playing a Blu-ray, the “auto-mode” of my receiver maps 5.1 sound to my 7.1 setup, so this is a bit of a shame. Secondly, when playing DTS HD 7.1 or Dolby Digital TrueHD 7.1, the sound that is supposed to go to the rear surround speakers, is played through the surround speakers instead. Again the rear surround speakers remain silent. I verified this with some surround sound test files.
I hope this can be fixed…