HDR Issues between devices

[sonysean]

Apologies if this isn't the best section for this question (it covers a few devices and I'm not sure which is the main issue).

I've not long had an LG B9 and Denon AVRX2600H set up and mostly everything has worked fine with no problem, except a couple of little problems which I'm not sure the cause of.

The main annoyance is my PS4 (original model) seems to occasionally "forget" it's HDR settings.
By this I mean some times when launching a HDR supported game, I will get the PS4's HDR settings come up like it's the first time HDR has been enabled, and I have to adjust the brightness settings.
This doesn't happen every time, which makes it stranger.
Also I've noticed while playing a HDR game, if a PS4 notification comes through (like a trophy or taking a screenshot), the sound cuts out for about a second.

I thought the issue could be perhaps I'm using an older version HDMI cable between the Denon and the PS4 but I can't see that being the issue as I believe you need a HDMI 2.0+ cable for HDR to work in the first place so I can't see how that would be the problem as it does work.

Edit: I fixed the Blu-ray player issue by connecting it to LAN and updating it to the latest firmware released back in 2014

 

[next010]

The PS4 uses an unusual from of 8-bit RGB HDR unlike the PS4 Pro which uses 10-bit YUV.

This could be the source of the compatibility issues with the Denon X2600H, is the firmware of the X2600 up to date ?

According to the specs of the X2600H it supports eARC, why not use that and connect the PS4 directly to the TV. LG added eARC PCM 7.1 support to the 9 series via firmware update so update TV too if you haven't in a while.

Have a look in WebOS sound output, I think they changed the below in different webos versions but pass-through is eARC mode basically
Under WebOS Sound->HDMI-ARC
Digital Sound Output = Pass-through
eARC = On

Connect the PS4 directly to the TV HDMI input, go into its sound settings and set it to LPCM 7.1