Dolby Vision support in Plex is a work in progress. There is no uniform support for the various DV profiles across all Plex clients. Search the thread linked below for “Dolby Vision” for details.
The only Plex client that plays 4K HDR video (HDR10 & DV) and passes TrueHD + Atmos (and dts-HD/dts:X) audio is the Nvidia Shield.
Other streaming devices (ATV, Roku, FireTV, etc) transcode/decode TrueHD and dts-HD to other formats such as AAC or PCM. Atmos and dts:X information is lost during the process.
Plex apps on smart TVs cannot pass TrueHD/dts-HD audio via HDMI-eARC due to TV manufacturer limitations.
If you purchase a Shield, strongly suggest you go with the 2019 Nvidia Shield Pro, not the “tube” model. The non-Pro tube model has problems with high-bit rate media, such as 4K HDR video with TrueHD audio. Search to forum with “Shield tube” or similar terms to see the reports.
See this thread for additional information:
