Hello Everyone, I've been a long time follower and reader of AVS but just now decided to put in my 2 cents since I'm also having a similar issue with the PS4.
First of all, My equipment is PS4, Onkyo TX-NR609 7.1 setup and Sony KDL-55HX800 ALL on HDMI (aftermarket)
PS4 settings and results on Main Interface (XMB): Main Audio Linear PCM= No Center speaker and Low volume (tones while going through options) on Front L & R speakers, Onkyo shows "Direct" and PCM in small letters
Main Audio Bitstream Dolby= Center speaker has normal volume (tones) as well as FR & FL, Onkyo Shows Dolby Digital EX
Main Audio Bitstream DTS= Center speaker has normal volume (tones) as well as FR & FL, Onkyo Shows DTS
PS4 settings and results on Shadow of Mordor: Main Audio Linear PCM= No center speaker in dialog or cut scenes only FR and FL speakers Onkyo shows "Direct" (didn't get to "play" since the audio wasn't working)
Main Audio Bitstream Dolby= Center speaker has normal volume as well as all speakers , Onkyo Shows Dolby Digital EX (audio sounds good during game play all speakers)
Main Audio Bitstream DTS= Center speaker has normal volume as well as all speakers , Onkyo Shows DTS (audio sounds good during game play all speakers)
In all 3 settings the display that shows the speakers that are working on the Onkyo shows all 7 speakers are active even if there is no sound from center speaker.
I also tried Call of Duty: Advance Warfare with the exact same results.
I tried the setting the Optical as output (no actual cable) and Onkyo shows the mentioned Dolby Pro Logic II.
Now... Is the Dolby Pro Logic II (or fake surround) better than the Bitstream Dolby & DTS settings? (Doesn't sound like it should be...)
No Problems while on Blu-Ray using Bitstream on Blu-Ray menu and it shows correct audio on Onkyo.
Questions are welcome as well as help with my question.
Please pardon the repetitiveness but I wanted to be as specific as possible to avoid confusion.
PS: Shadow of Mordor shows on the back of the case that it supports DTS 5.1 and Dolby Digital, Call Of Duty:AW shows it supports Dolby Digital
I'm guessing the best setting will depend on what format the game supports given a malfunctioning Linear PCM setting.