Plenty of issues all arround the web regaring transcoding with SmartTV Plex clients. My suggestion is simple:
Create an option in the server settings - Authorized Devices to override the default audio , video codec settings and support for a specific device. This way a plex admin can influence if a stream get transcoded or not. Plex can collect the information and use this to improve the defaults in plex profiles for future released of plex media server based on client/brand/model/app.
If the plex server doesn’t know specifics for a client Plex assumes it. People complaining about transcoding in SmartTV Native plex apps always get the solution buy to buy a shield, Roku, AppleTv or another Tv.
The SmartTV Plex client uses the built-in player of the SmartTV but doesn’t always know the specifics for every model. Some information from the Plex server.log
Jun 16, 2020 17:21:16.881 [0x7fe29a2b3700] DEBUG - [Now] Device is webOS (LG OLED65CX6LA).
Jun 16, 2020 17:21:16.934 [0x7fe29a2b3700] DEBUG - [Now] Profile is webOs
In this example we know that not all webOs tv’s are identical when it comes to supported codecs. Sony, Panasonic and LG models can change yearly in the codecs they support. In this case the Plex server assumes because it is webOs is should support DTS. LG stopped supporting DTS in the 2020 models. Sony on the other hand didn’t support DTS in the Android smart TVs but recently added it. In other words the codec supports changes from model to model.
When one codec fails the Plex server switches to a ‘failsafe’ profile but that will not use the true potention of the TV (and the potential Plex and the server Plex is running on) and will start transcoding in most cases.
You can do this with DLNA profiles. (link : Writing profiles for DLNA devices ) but who uses DLNA when you can run a Plex client on the TV?
Wouldn’t it ben ice if you can tick the boxes for a specific device to overrule the default settings?
Or
Do you have another solution and am I missing something? But don’t tell me to get a shield, Roku, AppleTv or another Tv. 
