Originally Posted by PlanetAVS
Educated Idiot, you're talking about Dolby Vision streamed movies right? Last I heard, Xbox forces DV at least for the Netflix app. Not sure if it also forces DV for other apps such as Vudu. If so, that would explain why it defaults to DV and you have to manually turn it off for non DV content such as Deadpool 2. Last I heard, Xbox doesn't support DV for disc play so I am guessing this is what is happening.
bearcatfan1976, as mentioned above Xbox doesn't support DV for disc play. That's why you have only been getting HDR10, even on DV discs. Rgarding your LG UHD player, it does not support the Sony DV profile. Therefore you'll only get HDR10 from that player on the 900F as well. Sorry, I'm in the same boat with my Philips UHD Dolby Vision capable player.
PlanetAVS, first off thanks for getting the discussion started on this panel and for your help as well as all the other contributors on here helping out us newbies with this panel. (EDIT: I saw PlanetAVS posting a lot of useful info so I mistakenly thought he started this thread and that was actually Cleveland Plasma. So thank you kindly sir.)
My issue was strictly with the Xbox One X playing UHD discs. It was odd, I could have sworn that when I first received the TV I tried a Dolby Vision disc using the Xbox One X and it played showing the badge and everything. Now I am believing this is not the case and I just got used to seeing it using the TVs own Netflix app possibly.
I decided to try my Xbox One X on another 4k panel, a TCL 615 as that panel also plays DV. What I found was that it clearly stated that this TV has an older version of DV that is not compatible with the Xbox so it will not even allow me to check the DV box in the Xbox settings (apparently, based on what you have said it would not matter anyway). At any rate, that TV does default to playing a DV UHD disc in HDR10 though automatically, no need to force HDR mode like i was having to do on the Sony.
So with the Xbox One X hooked up to the Sony X900F playing the same discs, with HDR mode set to auto, it would play in SDR, I was physically having to force it into HDR10 mode which seemed odd. So, looking at the Xbox settings I noticed that I had the Dolby Vision box checked (It was greyed out and non-selectable on the TCL). So I put in Atomic Blonde UHD disc which is DV and a strange error pop up "for optimal picture quality, connect your 4K Ultra HD player to a television that supports 4k Ultra HD with HDR." I had not seen this message before but I guess all the other discs I had watched so far were HDR10? So I tried unchecking the DV box in the Xbox settings and bingo, the TV now automatically switched to HDR10 mode to play Atomic Blonde.
So there appears to be an issue with having the DV box checked when playing HDR10 discs (and DV discs for that matter), at least for my setup (Xbox to Pioneer AVR with Xbox cable then to TV with Monoprice Certified cable). I see no reason to keep the DV box checked in the Xbox settings since, as you and others have pointed out, it does not support DV disc playing at the point. It does indeed change the Xbox Netflix app to not show DV but instead standard HDR doing it this way though but I am ok with the TV built in app for Netflix which currently does play DV anyway (I just lose out on the sound a little since it is piping DD+Atmos back to the receiver via ARC which I am assuming is of slightly lesser quality than true Atmos that the Xbox could play plugged right into the AVR?)
On a side note, doing a little net research, I ran across a reddit post where someone that swears they are an Xbox beta insider is indeed testing DV using UHD disc on the Xbox so it sounds like they are looking to possibly add it with a future update, which I would be happy about since I incorrectly thought it did support UHD DV playback (one of the reasons I justified buying it as a UHD player haha).
Hopefully my long winded post helps someone else.